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Vo-Dinh, Tuan

Overview:

Dr. Tuan Vo-Dinh is R. Eugene and Susie E. Goodson Distinguished Professor of Biomedical Engineering, Professor of Chemistry, and Director of The Fitzpatrick Institute for Photonics.


Dr. Vo-Dinh’s research activities and interests involve biophotonics, nanophotonics, plasmonics, laser-excited luminescence spectroscopy, room temperature phosphorimetry, synchronous luminescence spectroscopy, surface-enhanced Raman spectroscopy, field environmental instrumentation, fiberoptics sensors, nanosensors, biosensors and biochips for the protection of the environment and the improvement of human health.


Dr. Vo-Dinh’s research activities and interests include the development of advanced technologies and methods in biophotonics, nanophotonics, biosensors, biochips, plasmonics, multi-modality bioimaging, and theranostics (diagnostics and therapy) of diseases such as cancer and infectious diseases.


 


We have pioneered the development of a new generation of gene probes using surface-enhanced Raman scattering (SERS) detection with ‘Molecular Sentinels’ and Plasmonic Coupling Interference (PCI) molecular probes for multiplex and label-free detection of nucleic acid biomarkers (DNA, mRNA, microRNA) in early detection of cancer. The ability to simultaneously detect multiple oligonucleotide sequences is critical for many medical applications such as early diagnosis, high-throughput screening and systems biology research.


 


In genomic and precision medicine, nucleic acid-based molecular diagnosis is of paramount importance with many advantages such as high specificity, high sensitivity, serotyping capability, and mutation detection. Using SERS-based plasmonic nanobiosensors and nanochips, we are developing novel nucleic acid detection methods that can be integrated into lab-on-a-chip systems for point-of-care diagnosis  (e.g., breast, GI cancer) and global health applications (e.g., detection of malaria in South East Asia and Africa).


 


In multi-modality bioimaging, we are developing a novel multifunctional gold nanostar (GNS) probe for use in multi-modality bioimaging in pre-operative scans with PET, MRI and CT, intraoperative margin delineation with optical imaging, SERS and two-photon luminescence (TPL). The GNS can be used also for cancer treatment with plasmonics enhanced photothermal therapy (PTT), thus providing an excellent platform for seamless diagnostics and therapy (i.e., theranostics). Preclinical studies have shown its great potential for cancer diagnostics and therapeutics for future clinical translation.


 


Various nanobiosensors are being developed for monitoring intracellular parameters (e.g., pH) and biomolecular processes (e.g., apoptosis, caspases), opening the possibility for fundamental molecular biological research as well as biomedical applications (e.g., drug discovery) at the single cell level in a systems biology approach.

Positions:

R. Eugene and Susie E. Goodson Professor of Biomedical Engineering

Biomedical Engineering
Pratt School of Engineering

Professor of Biomedical Engineering

Biomedical Engineering
Pratt School of Engineering

Professor in the Department of Chemistry

Chemistry
Trinity College of Arts & Sciences

Faculty Network Member of The Energy Initiative

Duke University Energy Initiative
Institutes and Provost's Academic Units

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Director of the Fitzpatrick Institute for Photonics

Pratt School of Engineering
Pratt School of Engineering

Education:

B.S. 1971

B.S. — Swiss Federal Institute of Technology-EPFL Lausanne (Switzerland)

Ph.D. 1975

Ph.D. — Swiss Federal Institute of Technology-ETH Zurich (Switzerland)

News:

Grants:

New Methods for the Synthesis and Study of Bioactive Nitrogen-Containing Molecules

Administered By
Chemistry
AwardedBy
National Institutes of Health
Role
Collaborator
Start Date
January 05, 2017
End Date
December 31, 2020

Training in Medical Imaging

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
July 15, 2003
End Date
August 31, 2019

Nanoplasmonics-based molecular analysis tool for molecular biomarkers of cancer

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
September 08, 2015
End Date
July 31, 2018

Multi-functional Plasmonics Nanoprobes for Cellular Sensing and Imaging

Administered By
Biomedical Engineering
AwardedBy
Department of Energy
Role
Principal Investigator
Start Date
July 01, 2015
End Date
June 30, 2018

Duke University Program in Environmental Health

Administered By
Environmental Sciences and Policy
AwardedBy
National Institute of Environmental Health Sciences
Role
Mentor
Start Date
July 01, 2013
End Date
June 30, 2018

Special-shaped, low-cost, metal nanoparticles for advanced obscurants

Administered By
Biomedical Engineering
AwardedBy
Luna Innovations Inc.
Role
Principal Investigator
Start Date
January 23, 2017
End Date
May 31, 2018

Bloodborne tropical pathogen detection using multiple nanophotonic arrays

Administered By
Medicine, Infectious Diseases
AwardedBy
National Institutes of Health
Role
Co-Principal Investigator
Start Date
December 28, 2015
End Date
November 30, 2017

Flavoprotein Autofluorescence Imaging in AMD

Administered By
Ophthalmology
AwardedBy
National Institutes of Health
Role
Co Investigator
Start Date
September 30, 2015
End Date
September 29, 2017

Advanced Development of Medical Countermeasures to Enhance Platelet Regeneration

Administered By
Medicine, Cellular Therapy
AwardedBy
Department of Health and Human Services
Role
Project PI
Start Date
September 01, 2016
End Date
August 31, 2017

University Training Program in Biomolecular and Tissue Engineering

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Mentor
Start Date
July 01, 1994
End Date
June 30, 2017

Plasmonics-Active SERS Nanoplatforms for In Vivo Diagnostics

Administered By
Biomedical Engineering
AwardedBy
Defense Advanced Research Projects Agency
Role
Principal Investigator
Start Date
December 13, 2012
End Date
June 30, 2016

Nanoplatform for Tracking Adipose-Derived Stem Cell Migration

Administered By
Surgery, Plastic, Maxillofacial, and Oral Surgery
AwardedBy
Southeastern Society of Plastic and Reconstructive Surgeons
Role
Collaborator
Start Date
June 01, 2015
End Date
May 31, 2016

Does Cytoplasmic PELP1 Predict Resistance To Tamoxifen Chemoprevention?

Administered By
Medicine, Medical Oncology
AwardedBy
National Institutes of Health
Role
Co-Mentor
Start Date
September 01, 2010
End Date
August 31, 2015

Design and Synthesis of Plasmonic Hollow Nanoparticles for Advanced Obscurants

Administered By
Biomedical Engineering
AwardedBy
Luna Innovations Inc.
Role
Principal Investigator
Start Date
November 15, 2013
End Date
June 03, 2014

Europtrode XI (XI Conference on Optical Chemical sensors and Biosensors), April 1st- 4th, Barcelona, Spain 2012

Administered By
Biomedical Engineering
AwardedBy
National Science Foundation
Role
Principal Investigator
Start Date
April 01, 2012
End Date
September 30, 2012

Nanobiosensors for Probing Chemical Exposure and Metabolism Pathways of Individual Living Cells

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
July 17, 2007
End Date
March 31, 2012

Ultra-High Throughput Screening (u-HTS) Based on Surfaced Raman Scattering

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
March 02, 2006
End Date
November 30, 2011

Dynamic Testing of Signal Transduction Deregulation During Breast Cancer Initiation

Administered By
Biomedical Engineering
AwardedBy
US Army Medical Research and Materiel Command
Role
Principal Investigator
Start Date
July 01, 2009
End Date
June 30, 2011

Fiber Optics and III-Nitride Materials-based Chemical and Biological Sensing

Administered By
Biomedical Engineering
AwardedBy
Army Research Office
Role
Principal Investigator
Start Date
September 01, 2007
End Date
October 31, 2009

Advanced Multispectral Imaging (MSI) for Medical Diagnostics

Administered By
Biomedical Engineering
AwardedBy
National Institutes of Health
Role
Principal Investigator
Start Date
August 13, 2001
End Date
July 31, 2008
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Awards:

Award on Spectrochemical Analysis. American Chemical Society, Division of Analytical Chemistry.

Type
National
Awarded By
American Chemical Society, Division of Analytical Chemistry
Date
January 01, 2011

Fellows. American Institute for Medical and Biological Engineering.

Type
National
Awarded By
American Institute for Medical and Biological Engineering
Date
January 01, 2004

Director’s Award for Outstanding Accomplishments in Science and Technology. UT-Battelle.

Type
Other
Awarded By
UT-Battelle
Date
January 01, 2003

Distinguished Inventors Award. Battelle Memorial Institute.

Type
Other
Awarded By
Battelle Memorial Institute
Date
January 01, 2003

Distinguished Scientist of the Year Award. Oak Ridge National Laboratory.

Type
Other
Awarded By
Oak Ridge National Laboratory
Date
January 01, 2003

Fellow. International Society for Optics and Photonics.

Type
National
Awarded By
International Society for Optics and Photonics
Date
January 01, 2000

RD-100 Award for Most Technologically Significant Advance in R&D (Multifunctional Biochip). R&D Magazine.

Type
International
Awarded By
R&D Magazine
Date
January 01, 1999

Lockheed Martin Commercialization Award. Lockheed Martin Corporation.

Type
Other
Awarded By
Lockheed Martin Corporation
Date
January 01, 1998

AMSE Award, American Museum of Science and Technology (BiOptics Technology). American Museum of Science and Technology.

Type
State
Awarded By
American Museum of Science and Technology
Date
January 01, 1997

BER-50 Award for Exceptional Service for a Health Citizenry. US Department of Energy.

Type
National
Awarded By
US Department of Energy
Date
January 01, 1997

Inventor of the Year Award. Tennessee Inventors Association.

Type
State
Awarded By
Tennessee Inventors Association
Date
January 01, 1996

RD-100 Award for Most Technologically Significant Advance in R&D (SERS Gene Probe). R&D Magazine.

Type
International
Awarded By
R&D Magazine
Date
January 01, 1996

Award for Excellence in Technology Transfer (SERODS Technology). Federal Laboratory Consortium.

Type
National
Awarded By
Federal Laboratory Consortium
Date
January 01, 1995

RD-100 Award for Most Technologically Significant Product of the Year (PCB Spot Test). R&D Magazine.

Type
International
Awarded By
R&D Magazine
Date
January 01, 1994

Inventors International Hall of Fame Award. Inventors Clubs of America.

Type
National
Awarded By
Inventors Clubs of America
Date
January 01, 1992

Inventors International Hall of Fame Award. Inventors Clubs of America.

Type
National
Awarded By
Inventors Clubs of America
Date
January 01, 1992

RD-100 Award for Most Technologically Significant Product of the Year (SERODS Technology). R&D Magazine.

Type
International
Awarded By
R&D Magazine
Date
January 01, 1992

Scientist of the Year. Oak Ridge National Laboratory.

Type
Other
Awarded By
Oak Ridge National Laboratory
Date
January 01, 1992

Thomas Jefferson Award. Martin Marietta Corporation.

Type
Other
Awarded By
Martin Marietta Corporation
Date
January 01, 1992

Languedoc-Rousillon Medal. University of Perpignan (France).

Type
National
Awarded By
University of Perpignan (France)
Date
January 01, 1989

Gold Medal Spectroscopy Award. Society for Applied Spectroscopy.

Type
International
Awarded By
Society for Applied Spectroscopy
Date
January 01, 1988

RD-100 Award for Most Significant Technological Advance in R&D (Fluoroimmunosensor). R&D Magazine.

Type
International
Awarded By
R&D Magazine
Date
January 01, 1987

Award for Excellence in Technology Transfer. Federal Laboratory Consortium.

Type
National
Awarded By
Federal Laboratory Consortium
Date
January 01, 1986

RD 100 Award for Most Significant Technological Advance in Research & Dev (PNA Dosimeter). R&D Magazine.

Type
National
Awarded By
R&D Magazine
Date
January 01, 1981

Publications:

Sensitive DNA detection and SNP discrimination using ultrabright SERS nanorattles and magnetic beads for malaria diagnostics.

One of the major obstacles to implement nucleic acid-based molecular diagnostics at the point-of-care (POC) and in resource-limited settings is the lack of sensitive and practical DNA detection methods that can be seamlessly integrated into portable platforms. Herein we present a sensitive yet simple DNA detection method using a surface-enhanced Raman scattering (SERS) nanoplatform: the ultrabright SERS nanorattle. The method, referred to as the nanorattle-based method, involves sandwich hybridization of magnetic beads that are loaded with capture probes, target sequences, and ultrabright SERS nanorattles that are loaded with reporter probes. Upon hybridization, a magnet was applied to concentrate the hybridization sandwiches at a detection spot for SERS measurements. The ultrabright SERS nanorattles, composed of a core and a shell with resonance Raman reporters loaded in the gap space between the core and the shell, serve as SERS tags for signal detection. Using this method, a specific DNA sequence of the malaria parasite Plasmodium falciparum could be detected with a detection limit of approximately 100 attomoles. Single nucleotide polymorphism (SNP) discrimination of wild type malaria DNA and mutant malaria DNA, which confers resistance to artemisinin drugs, was also demonstrated. These test models demonstrate the molecular diagnostic potential of the nanorattle-based method to both detect and genotype infectious pathogens. Furthermore, the method's simplicity makes it a suitable candidate for integration into portable platforms for POC and in resource-limited settings applications.

Authors
Ngo, HT; Gandra, N; Fales, AM; Taylor, SM; Vo-Dinh, T
MLA Citation
Ngo, HT, Gandra, N, Fales, AM, Taylor, SM, and Vo-Dinh, T. "Sensitive DNA detection and SNP discrimination using ultrabright SERS nanorattles and magnetic beads for malaria diagnostics." Biosensors & bioelectronics 81 (July 2016): 8-14.
PMID
26913502
Source
epmc
Published In
Biosensors and Bioelectronics
Volume
81
Publish Date
2016
Start Page
8
End Page
14
DOI
10.1016/j.bios.2016.01.073

Tunable and amplified Raman gold nanoprobes for effective tracking (TARGET): in vivo sensing and imaging.

We describe the development of a highly tunable, physiologically stable, and ultra-bright Raman probe, named as TARGET (Tunable and Amplified Raman Gold Nanoprobes for Effective Tracking), for in vitro and in vivo surface-enhanced Raman scattering (SERS) applications. The TARGET structure consists of a gold core inside a larger gold shell with a tunable interstitial gap similar to a "nanorattle" structure. The combination of galvanic replacement and the seed mediated growth method was employed to load Raman reporter molecules and subsequently close the pores to prevent leaking and degradation of reporters under physiologically extreme conditions. Precise tuning of the core-shell gap width, core size, and shell thickness allows us to modulate the plasmonic effect and achieve a maximum electric-field (E-field) intensity. The interstitial gap of TARGET nanoprobes can be designed to exhibit a plasmon absorption band at 785 nm, which is in resonance with the dye absorption maximum and lies in the "tissue optical window", resulting in ultra-bright SERS signals for in vivo studies. The results of in vivo measurements of TARGETs in laboratory mice illustrated the usefulness of these nanoprobes for medical sensing and imaging.

Authors
Gandra, N; Hendargo, HC; Norton, SJ; Fales, AM; Palmer, GM; Vo-Dinh, T
MLA Citation
Gandra, N, Hendargo, HC, Norton, SJ, Fales, AM, Palmer, GM, and Vo-Dinh, T. "Tunable and amplified Raman gold nanoprobes for effective tracking (TARGET): in vivo sensing and imaging." Nanoscale 8.16 (April 11, 2016): 8486-8494.
PMID
27064259
Source
epmc
Published In
Nanoscale
Volume
8
Issue
16
Publish Date
2016
Start Page
8486
End Page
8494
DOI
10.1039/c5nr08980h

Tracking mesenchymal stromal cells using an ultra-bright TAT-functionalized plasmonic-active nanoplatform.

High-resolution tracking of stem cells remains a challenging task. An ultra-bright contrast agent with extended intracellular retention is suitable for in vivo high-resolution tracking of stem cells following the implantation. Here, a plasmonic-active nanoplatform was developed for tracking mesenchymal stromal cells (MSCs) in mice. The nanoplatform consisted of TAT peptide-functionalized gold nanostars (TAT-GNS) that emit ultra-bright two-photon photoluminescence capable of tracking MSCs under high-resolution optical imaging. In vitro experiment showed TAT-GNS-labeled MSCs retained a similar differentiability to that of non-labeled MSCs controls. Due to their star shape, TAT-GNS exhibited greater intracellular retention than that of commercial Q-Tracker. In vivo imaging of TAT-GNS-labeled MSCs five days following intra-arterial injections in mice kidneys showed possible MSCs implantation in juxta-glomerular (JG) regions, but non-specifically in glomeruli and afferent arterioles as well. With future design to optimize GNS labeling specificity and clearance, plasmonic-active nanoplatforms may be a useful intracellular tracking tool for stem cell research. An ultra-bright intracellular contrast agent is developed using TAT peptide-functionalized gold nanostars (TAT-GNS). It poses minimal influence on the stem cell differentiability. It exhibits stronger two-photon photoluminescence and superior labeling efficiency than commercial Q-Tracker. Following renal implantation, some TAT-GNS-labeled MSCs permeate blood vessels and migrate to the juxta-glomerular region.

Authors
Yuan, H; Gomez, JA; Chien, JS; Zhang, L; Wilson, CM; Li, S; Fales, AM; Liu, Y; Grant, GA; Mirotsou, M; Dzau, VJ; Vo-Dinh, T
MLA Citation
Yuan, H, Gomez, JA, Chien, JS, Zhang, L, Wilson, CM, Li, S, Fales, AM, Liu, Y, Grant, GA, Mirotsou, M, Dzau, VJ, and Vo-Dinh, T. "Tracking mesenchymal stromal cells using an ultra-bright TAT-functionalized plasmonic-active nanoplatform." Journal of biophotonics 9.4 (April 2016): 406-413.
PMID
27095616
Source
epmc
Published In
Journal of biophotonics
Volume
9
Issue
4
Publish Date
2016
Start Page
406
End Page
413
DOI
10.1002/jbio.201500173

Plasmonic SERS biosensing nanochips for DNA detection.

The development of rapid, cost-effective DNA detection methods for molecular diagnostics at the point-of-care (POC) has been receiving increasing interest. This article reviews several DNA detection techniques based on plasmonic-active nanochip platforms developed in our laboratory over the last 5 years, including the molecular sentinel-on-chip (MSC), the multiplex MSC, and the inverse molecular sentinel-on-chip (iMS-on-Chip). DNA probes were used as the recognition elements, and surface-enhanced Raman scattering (SERS) was used as the signal detection method. Sensing mechanisms were based on hybridization of target sequences and DNA probes, resulting in a distance change between SERS reporters and the nanochip's plasmonic-active surface. As the field intensity of the surface plasmon decays exponentially as a function of distance, the distance change in turn affects SERS signal intensity, thus indicating the presence and capture of the target sequences. Our techniques were single-step DNA detection techniques. Target sequences were detected by simple delivery of sample solutions onto DNA probe-functionalized nanochips and measuring the SERS signal after appropriate incubation times. Target sequence labeling or washing to remove unreacted components was not required, making the techniques simple, easy-to-use, and cost-effective. The usefulness of the nanochip platform-based techniques for medical diagnostics was illustrated by the detection of host genetic biomarkers for respiratory viral infection and of the dengue virus gene.

Authors
Ngo, HT; Wang, H-N; Fales, AM; Vo-Dinh, T
MLA Citation
Ngo, HT, Wang, H-N, Fales, AM, and Vo-Dinh, T. "Plasmonic SERS biosensing nanochips for DNA detection." Analytical and bioanalytical chemistry 408.7 (March 2016): 1773-1781. (Review)
PMID
26547189
Source
epmc
Published In
Analytical and Bioanalytical Chemistry
Volume
408
Issue
7
Publish Date
2016
Start Page
1773
End Page
1781
DOI
10.1007/s00216-015-9121-4

In vivo detection of SERS-encoded plasmonic nanostars in human skin grafts and live animal models.

Surface-enhanced Raman scattering (SERS)-active plasmonic nanomaterials have become a promising agent for molecular imaging and multiplex detection. Among the wide variety of plasmonics-active nanoparticles, gold nanostars offer unique plasmon properties that efficiently induce strong SERS signals. Furthermore, nanostars, with their small core size and multiple long thin branches, exhibit high absorption cross sections that are tunable in the near-infrared region of the tissue optical window, rendering them efficient for in vivo spectroscopic detection. This study investigated the use of SERS-encoded gold nanostars for in vivo detection. Ex vivo measurements were performed using human skin grafts to investigate the detection of SERS-encoded nanostars through tissue. We also integrated gold nanostars into a biocompatible scaffold to aid in performing in vivo spectroscopic analyses. In this study, for the first time, we demonstrate in vivo SERS detection of gold nanostars using small animal (rat) as well as large animal (pig) models. The results of this study establish the usefulness and potential of SERS-encoded gold nanostars for future use in long-term in vivo analyte sensing.

Authors
Register, JK; Fales, AM; Wang, H-N; Norton, SJ; Cho, EH; Boico, A; Pradhan, S; Kim, J; Schroeder, T; Wisniewski, NA; Klitzman, B; Vo-Dinh, T
MLA Citation
Register, JK, Fales, AM, Wang, H-N, Norton, SJ, Cho, EH, Boico, A, Pradhan, S, Kim, J, Schroeder, T, Wisniewski, NA, Klitzman, B, and Vo-Dinh, T. "In vivo detection of SERS-encoded plasmonic nanostars in human skin grafts and live animal models." Analytical and bioanalytical chemistry 407.27 (November 2015): 8215-8224.
PMID
26337748
Source
epmc
Published In
Analytical and Bioanalytical Chemistry
Volume
407
Issue
27
Publish Date
2015
Start Page
8215
End Page
8224
DOI
10.1007/s00216-015-8939-0

Fano resonance in a gold nanosphere with a J-aggregate coating.

We present a facile method to induce J-aggregate formation on gold nanospheres in colloidal solution using polyvinylsulfate. The nanoparticle J-aggregate complex results in an absorption spectrum with a split lineshape due to plasmon-exciton coupling, i.e. via the formation of upper and lower plexcitonic branches. The use of nanoparticles with different plasmon resonances alters the position of the upper plexcitonic band while the lower band remains at the same wavelength. This splitting is investigated theoretically, and shown analytically to arise from Fano resonance between the plasmon of the gold nanoparticles and exciton of the J-aggregates. A theoretical simulation of a J-aggregate coated and uncoated gold nanosphere produces an absorption spectrum that shows good agreement with the experimentally measured spectra.

Authors
Fales, AM; Norton, SJ; Crawford, BM; DeLacy, BG; Vo-Dinh, T
MLA Citation
Fales, AM, Norton, SJ, Crawford, BM, DeLacy, BG, and Vo-Dinh, T. "Fano resonance in a gold nanosphere with a J-aggregate coating." Physical chemistry chemical physics : PCCP 17.38 (October 2015): 24931-24936.
PMID
26344505
Source
epmc
Published In
Physical Chemistry Chemical Physics
Volume
17
Issue
38
Publish Date
2015
Start Page
24931
End Page
24936
DOI
10.1039/c5cp03277f

Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection.

Developing a simple and efficient nucleic acid detection technology is essential for clinical diagnostics. Here, we describe a new conceptually simple and selective "turn on" plasmonics-based nanobiosensor, which integrates non-enzymatic DNA strand-displacement hybridization for specific nucleic acid target identification with surface-enhanced Raman scattering (SERS) detection. This SERS nanobiosensor is a target label-free, and rapid nanoparticle-based biosensing system using a homogeneous assay format that offers a simple and efficient tool for nucleic acid diagnostics. Our results showed that the nanobiosensor provided a limit of detection of ~0.1nM (200amol) in the current bioassay system, and exhibited high specificity for single nucleotide mismatch discrimination.Surface-enhanced Raman scattering (SERS) is a sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces. The enhancement means that the technique may even detect single molecules. In this article, the authors describe a simple and efficient nucleic acid detection technology using SERS, with "OFF-to-ON" signal switch upon nucleic acid target identification and capture, which provides high sensitivity and specificity for single nucleotide mismatch discrimination. This new technology will be most welcomed in clinical diagnostics.

Authors
Wang, H-N; Fales, AM; Vo-Dinh, T
MLA Citation
Wang, H-N, Fales, AM, and Vo-Dinh, T. "Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection." Nanomedicine : nanotechnology, biology, and medicine 11.4 (May 2015): 811-814.
PMID
25652895
Source
epmc
Published In
Nanomedicine: Nanotechnology, Biology and Medicine
Volume
11
Issue
4
Publish Date
2015
Start Page
811
End Page
814
DOI
10.1016/j.nano.2014.12.012

Multiplex DNA biosensor for viral infection diagnosis using SERS molecular sentinel-on-chip

© Springer International Publishing Switzerland 2015.The development of sensitive and selective techniques for multiplex detection of DNA biomarkers is paramount for clinical diagnosis. Various multiplex DNA detection techniques have been reported. However, most of these techniques require multiple incubation and/or washing steps or target sequence labeling. In this work, we demonstrated a unique multiplex DNA biosensor for viral infection diagnosis using the surface-enhanced Raman scattering (SERS) “Molecular Sentinelon- Chip” (MSC) technique. The sensing mechanism is based upon the change of SERS intensity when Raman labels tagged at 3′-ends of molecular sentinel nanoprobes are physically displaced from the Nanowave chip’s surface upon target DNA hybridization. SERS measurements were performed immediately following a single hybridization reaction between the target single-stranded DNA (ssDNA) sequences and the complementary molecular sentinel nanoprobes immobilized on the Nanowave chip without requiring target labeling (i.e., label-free assay), secondary hybridization, or post-hybridization washing, thus reducing the assay time and lowering cost. Two nucleic acid transcripts, interferon alpha-inducible protein 27 (IFI27) and interferon-induced protein 44-like (IFI44L), are used as model systems for the multiplex detection concept demonstration. These two genes are well known for their critical role in host immune response to viral infections and can be used as molecular signature for viral infection diagnosis. The results indicate the effectiveness and potential of the MSC technology for multiplex DNA detection for point-ofcare diagnostics and global health applications.

Authors
Ngo, HT; Wang, HN; Burke, T; Woods, C; Ginsburg, GS; Vo-Dinh, T
MLA Citation
Ngo, HT, Wang, HN, Burke, T, Woods, C, Ginsburg, GS, and Vo-Dinh, T. "Multiplex DNA biosensor for viral infection diagnosis using SERS molecular sentinel-on-chip." January 1, 2015.
Source
scopus
Published In
Ifmbe Proceedings
Volume
46
Publish Date
2015
Start Page
15
End Page
20
DOI
10.1007/978-3-319-11776-8_4

Plasmonics-Active gold nanostars for chemical and biological sensing using SERS detection

© 2015 SPIE.Surface-enhanced Raman scattering (SERS) provides a non-destructive sensing method with high sensitivity and multiplex detection capability since SERS takes advantage of high enhancement from surface plasmon resonance and unique â€fingerprint†spectral signature using Raman spectroscopy. Our group has developed a unique plasmonics-Active nanoparticle, gold nanostars, with tunable plasmonics in near-infrared (NIR) â€tissue optical window†without using toxic surfactant. We present their applications for chemical and biological sensing with SERS method as well as theoretical studies to investigate and confirm experimentally measured SERS results.

Authors
Liu, Y; Yuan, H; Fales, AM; Vo-Dinh, T
MLA Citation
Liu, Y, Yuan, H, Fales, AM, and Vo-Dinh, T. "Plasmonics-Active gold nanostars for chemical and biological sensing using SERS detection." January 1, 2015.
Source
scopus
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
9486
Publish Date
2015
DOI
10.1117/12.2182123

SERS nanosensors and nanoreporters: golden opportunities in biomedical applications.

This article provides an overview of recent developments and applications of surface-enhanced Raman scattering (SERS) nanosensors and nanoreporters in our laboratory for use in biochemical monitoring, medical diagnostics, and therapy. The design and fabrication of different types of plasmonics-active nanostructures are discussed. The SERS nanosensors can be used in various applications including pH sensing, protein detection, and gene diagnostics. For DNA detection the 'Molecular Sentinel' nanoprobe can be used as a homogenous bioassay in solution or on a chip platform. Gold nanostars provide an excellent multi-modality theranostic platform, combining Raman and SERS with two-photon luminescence (TPL) imaging as well as photodynamic therapy (PDT), and photothermal therapy (PTT). Plasmonics-enhanced and optically modulated delivery of nanostars into brain tumor in live animals was demonstrated; photothermal treatment of tumor vasculature may induce inflammasome activation, thus increasing the permeability of the blood brain-tumor barrier. The imaging method using TPL of gold nanostars provides an unprecedented spatial selectivity for enhanced targeted nanostar delivery to cortical tumor tissue. A quintuple-modality nanoreporter based on gold nanostars for SERS, TPL, magnetic resonance imaging (MRI), computed tomography (CT), and PTT has recently been developed. The possibility of combining spectral selectivity and high sensitivity of the SERS process with the inherent molecular specificity of bioreceptor-based nanoprobes provides a unique multiplex and selective diagnostic modality. Several examples of optical detection using SERS in combination with other detection and treatment modalities are discussed to illustrate the usefulness and potential of SERS nanosensors and nanoreporters for medical applications.

Authors
Vo-Dinh, T; Liu, Y; Fales, AM; Ngo, H; Wang, H-N; Register, JK; Yuan, H; Norton, SJ; Griffin, GD
MLA Citation
Vo-Dinh, T, Liu, Y, Fales, AM, Ngo, H, Wang, H-N, Register, JK, Yuan, H, Norton, SJ, and Griffin, GD. "SERS nanosensors and nanoreporters: golden opportunities in biomedical applications." Wiley interdisciplinary reviews. Nanomedicine and nanobiotechnology 7.1 (January 2015): 17-33.
PMID
25316579
Source
epmc
Published In
Wiley interdisciplinary reviews. Nanomedicine and nanobiotechnology
Volume
7
Issue
1
Publish Date
2015
Start Page
17
End Page
33
DOI
10.1002/wnan.1283

Plasmonic gold nanostars for multi-modality sensing and diagnostics.

Gold nanostars (AuNSs) are unique systems that can provide a novel multifunctional nanoplatform for molecular sensing and diagnostics. The plasmonic absorption band of AuNSs can be tuned to the near infrared spectral range, often referred to as the "tissue optical window", where light exhibits minimal absorption and deep penetration in tissue. AuNSs have been applied for detecting disease biomarkers and for biomedical imaging using multi-modality methods including surface-enhanced Raman scattering (SERS), two-photon photoluminescence (TPL), magnetic resonance imaging (MRI), positron emission tomography (PET), and X-ray computer tomography (CT) imaging. In this paper, we provide an overview of the recent development of plasmonic AuNSs in our laboratory for biomedical applications and highlight their potential for future translational medicine as a multifunctional nanoplatform.

Authors
Liu, Y; Yuan, H; Kersey, FR; Register, JK; Parrott, MC; Vo-Dinh, T
MLA Citation
Liu, Y, Yuan, H, Kersey, FR, Register, JK, Parrott, MC, and Vo-Dinh, T. "Plasmonic gold nanostars for multi-modality sensing and diagnostics." Sensors (Basel, Switzerland) 15.2 (January 2015): 3706-3720. (Review)
PMID
25664431
Source
epmc
Published In
Sensors (Basel, Switzerland)
Volume
15
Issue
2
Publish Date
2015
Start Page
3706
End Page
3720
DOI
10.3390/s150203706

Inherently stealthy and highly tumor-selective gold nanoraspberries for photothermal cancer therapy.

Owing to their unique optical properties such as large absorption and scattering cross section and large enhancement of electromagnetic field at the surface, plasmonic nanostructures have received extensive attention as a highly promising class of materials for nano-oncology. Most of the existing plasmonic nanostructures require extensive post-synthesis treatments and biofunctionalization routines to mitigate their cytotoxicity and/or make them tumor-specific. Here, we report one-pot synthesis of a novel class of plasmonic nanostructures, namely, gold nanoraspberries (GRBs) with tunable size and localized surface plasmon resonance by using a naturally abundant polysaccharide, chitosan, which acts as a template and capping agent. Significantly, the GRBs, which do not require any further biofunctionalization, exhibit excellent selectivity to tumor cells, thus enabling locoregional therapy at the cellular level. We demonstrate the tumor-selectivity of GRBs by photothermal ablation of tumor cells selectively from their co-culture with normal cells. The simple, scalable and tumor-selective nature of GRBs makes them excellent candidates for translational plasmonics-based nanomedicine.

Authors
Gandra, N; Portz, C; Nergiz, SZ; Fales, A; Vo-Dinh, T; Singamaneni, S
MLA Citation
Gandra, N, Portz, C, Nergiz, SZ, Fales, A, Vo-Dinh, T, and Singamaneni, S. "Inherently stealthy and highly tumor-selective gold nanoraspberries for photothermal cancer therapy." Scientific reports 5 (January 2015): 10311-.
PMID
25974150
Source
epmc
Published In
Scientific Reports
Volume
5
Publish Date
2015
Start Page
10311
DOI
10.1038/srep10311

A Plasmonic Gold Nanostar Theranostic Probe for In Vivo Tumor Imaging and Photothermal Therapy.

Nanomedicine has attracted increasing attention in recent years, because it offers great promise to provide personalized diagnostics and therapy with improved treatment efficacy and specificity. In this study, we developed a gold nanostar (GNS) probe for multi-modality theranostics including surface-enhanced Raman scattering (SERS) detection, x-ray computed tomography (CT), two-photon luminescence (TPL) imaging, and photothermal therapy (PTT). We performed radiolabeling, as well as CT and optical imaging, to investigate the GNS probe's biodistribution and intratumoral uptake at both macroscopic and microscopic scales. We also characterized the performance of the GNS nanoprobe for in vitro photothermal heating and in vivo photothermal ablation of primary sarcomas in mice. The results showed that 30-nm GNS have higher tumor uptake, as well as deeper penetration into tumor interstitial space compared to 60-nm GNS. In addition, we found that a higher injection dose of GNS can increase the percentage of tumor uptake. We also demonstrated the GNS probe's superior photothermal conversion efficiency with a highly concentrated heating effect due to a tip-enhanced plasmonic effect. In vivo photothermal therapy with a near-infrared (NIR) laser under the maximum permissible exposure (MPE) led to ablation of aggressive tumors containing GNS, but had no effect in the absence of GNS. This multifunctional GNS probe has the potential to be used for in vivo biosensing, preoperative CT imaging, intraoperative detection with optical methods (SERS and TPL), as well as image-guided photothermal therapy.

Authors
Liu, Y; Ashton, JR; Moding, EJ; Yuan, H; Register, JK; Fales, AM; Choi, J; Whitley, MJ; Zhao, X; Qi, Y; Ma, Y; Vaidyanathan, G; Zalutsky, MR; Kirsch, DG; Badea, CT; Vo-Dinh, T
MLA Citation
Liu, Y, Ashton, JR, Moding, EJ, Yuan, H, Register, JK, Fales, AM, Choi, J, Whitley, MJ, Zhao, X, Qi, Y, Ma, Y, Vaidyanathan, G, Zalutsky, MR, Kirsch, DG, Badea, CT, and Vo-Dinh, T. "A Plasmonic Gold Nanostar Theranostic Probe for In Vivo Tumor Imaging and Photothermal Therapy." Theranostics 5.9 (January 2015): 946-960.
Website
http://hdl.handle.net/10161/11045
PMID
26155311
Source
epmc
Published In
Theranostics
Volume
5
Issue
9
Publish Date
2015
Start Page
946
End Page
960
DOI
10.7150/thno.11974

Time-Resolved Synchronous Fluorescence for Biomedical Diagnosis.

This article presents our most recent advances in synchronous fluorescence (SF) methodology for biomedical diagnostics. The SF method is characterized by simultaneously scanning both the excitation and emission wavelengths while keeping a constant wavelength interval between them. Compared to conventional fluorescence spectroscopy, the SF method simplifies the emission spectrum while enabling greater selectivity, and has been successfully used to detect subtle differences in the fluorescence emission signatures of biochemical species in cells and tissues. The SF method can be used in imaging to analyze dysplastic cells in vitro and tissue in vivo. Based on the SF method, here we demonstrate the feasibility of a time-resolved synchronous fluorescence (TRSF) method, which incorporates the intrinsic fluorescent decay characteristics of the fluorophores. Our prototype TRSF system has clearly shown its advantage in spectro-temporal separation of the fluorophores that were otherwise difficult to spectrally separate in SF spectroscopy. We envision that our previously-tested SF imaging and the newly-developed TRSF methods will combine their proven diagnostic potentials in cancer diagnosis to further improve the efficacy of SF-based biomedical diagnostics.

Authors
Zhang, X; Fales, A; Vo-Dinh, T
MLA Citation
Zhang, X, Fales, A, and Vo-Dinh, T. "Time-Resolved Synchronous Fluorescence for Biomedical Diagnosis." Sensors (Basel, Switzerland) 15.9 (January 2015): 21746-21759.
Website
http://hdl.handle.net/10161/11299
PMID
26404289
Source
epmc
Published In
Sensors (Basel, Switzerland)
Volume
15
Issue
9
Publish Date
2015
Start Page
21746
End Page
21759
DOI
10.3390/s150921746

Silver embedded nanostars for SERS with internal reference (SENSIR)

Authors
Fales, AM; Vo-Dinh, T
MLA Citation
Fales, AM, and Vo-Dinh, T. "Silver embedded nanostars for SERS with internal reference (SENSIR)." J. Mater. Chem. C 3.28 (2015): 7319-7324.
Source
crossref
Published In
Journal of Materials Chemistry C
Volume
3
Issue
28
Publish Date
2015
Start Page
7319
End Page
7324
DOI
10.1039/C5TC01296A

DNA bioassay-on-chip using SERS detection for dengue diagnosis.

A novel DNA bioassay-on-chip using surface-enhanced Raman scattering (SERS) on a bimetallic nanowave chip is presented. In this bioassay, SERS signals were measured after a single reaction on the chip's surface without any washing step, making it simple-to-use and reducing the reagent cost. Using the technique, specific oligonucleotide sequences of the dengue virus 4 were detected.

Authors
Ngo, HT; Wang, H-N; Fales, AM; Nicholson, BP; Woods, CW; Vo-Dinh, T
MLA Citation
Ngo, HT, Wang, H-N, Fales, AM, Nicholson, BP, Woods, CW, and Vo-Dinh, T. "DNA bioassay-on-chip using SERS detection for dengue diagnosis." The Analyst 139.22 (November 2014): 5655-5659.
PMID
25248522
Source
epmc
Published In
The Analyst
Volume
139
Issue
22
Publish Date
2014
Start Page
5655
End Page
5659
DOI
10.1039/c4an01077a

Direct analysis of traditional Chinese medicines using Surface-Enhanced Raman Scattering (SERS).

Surface-Enhanced Raman Scattering (SERS) spectrometry provides an excellent tool to characterize chemical constituents in Traditional Chinese Medicines (TCMs) without requiring separation and extraction procedures. This study involved the use of SERS to analyze two TCMs, namely Coptis chinensis and Phellodendron amurense, and their main active constituent, berberine. Using silver nanospheres as SERS-active probes, the decoctions of two raw TCMs and their counterfeits were analyzed. Density functional theory (DFT) was used to calculate the expected Raman spectrum of berberine, and liquid chromatography- mass spectrometry (LC-MS) was used as a comparative technique to quantify the amount of berberine in the samples. The results of the SERS measurements were consistent with the results of DFT calculations and LCMS analyses. To our knowledge, this is the first time that the potential of SERS was demonstrated as a sensitive, rapid, and non-destructive method to qualitatively and quantitatively analyze the active constituents in raw TCM products.

Authors
Zhao, J; Liu, Y; Fales, AM; Register, J; Yuan, H; Vo-Dinh, T
MLA Citation
Zhao, J, Liu, Y, Fales, AM, Register, J, Yuan, H, and Vo-Dinh, T. "Direct analysis of traditional Chinese medicines using Surface-Enhanced Raman Scattering (SERS)." Drug testing and analysis 6.10 (October 2014): 1063-1068.
PMID
24522956
Source
epmc
Published In
Drug Testing and Analysis
Volume
6
Issue
10
Publish Date
2014
Start Page
1063
End Page
1068
DOI
10.1002/dta.1612

Preparation of Liquid and Solid Samples

Authors
Cullum, BM; Vo-Dinh, T
MLA Citation
Cullum, BM, and Vo-Dinh, T. "Preparation of Liquid and Solid Samples." Handbook of Spectroscopy: Second, Enlarged Edition. June 9, 2014. 1-14.
Source
scopus
Volume
1-4
Publish Date
2014
Start Page
1
End Page
14
DOI
10.1002/9783527654703.ch1

Multiplex detection of disease biomarkers using SERS molecular sentinel-on-chip.

Developing techniques for multiplex detection of disease biomarkers is important for clinical diagnosis. In this work, we have demonstrated for the first time the feasibility of multiplex detection of genetic disease biomarkers using the surface-enhanced Raman scattering (SERS)-based molecular sentinel-on-chip (MSC) diagnostic technology. The molecular sentinel (MS) sensing mechanism is based upon the decrease of SERS intensity when Raman labels tagged at 3'-ends of MS nanoprobes are physically displaced from the nanowave chip's surface upon DNA hybridization. The use of bimetallic layer (silver and gold) for the nanowave fabrication was investigated. SERS measurements were performed immediately following a single hybridization reaction between the target single-stranded DNA sequences and the complementary MS nanoprobes immobilized on the nanowave chip without requiring target labeling (i.e., label-free), secondary hybridization, or post-hybridization washing, thus shortening the assay time and reducing cost. Two nucleic acid transcripts, interferon alpha-inducible protein 27 and interferon-induced protein 44-like, are used as model systems for the multiplex detection concept demonstration. These two genes are well known for their critical role in host immune response to viral infection and can be used as molecular signature for viral infection diagnosis. The results indicate the potential of the MSC technology for nucleic acid biomarker multiplex detection.

Authors
Ngo, HT; Wang, H-N; Burke, T; Ginsburg, GS; Vo-Dinh, T
MLA Citation
Ngo, HT, Wang, H-N, Burke, T, Ginsburg, GS, and Vo-Dinh, T. "Multiplex detection of disease biomarkers using SERS molecular sentinel-on-chip." Analytical and bioanalytical chemistry 406.14 (May 2014): 3335-3344.
PMID
24577572
Source
epmc
Published In
Analytical and Bioanalytical Chemistry
Volume
406
Issue
14
Publish Date
2014
Start Page
3335
End Page
3344
DOI
10.1007/s00216-014-7648-4

Introduction to the Issue on Nanobiophotonics

Authors
Ilev, IK; Tunnell, J; Chen, Y; Hildebrandt, N; Dholakia, K; Vo-Dinh, T
MLA Citation
Ilev, IK, Tunnell, J, Chen, Y, Hildebrandt, N, Dholakia, K, and Vo-Dinh, T. "Introduction to the Issue on Nanobiophotonics." IEEE Journal of Selected Topics in Quantum Electronics 20.3 (May 2014): 3-6.
Source
crossref
Published In
IEEE Journal of Selected Topics in Quantum Electronics
Volume
20
Issue
3
Publish Date
2014
Start Page
3
End Page
6
DOI
10.1109/JSTQE.2014.2319791

Plasmonics-enhanced and optically modulated delivery of gold nanostars into brain tumor.

Plasmonics-active gold nanostars exhibiting strong imaging contrast and efficient photothermal transduction were synthesized for a novel pulsed laser-modulated plasmonics-enhanced brain tumor microvascular permeabilization. We demonstrate a selective, optically modulated delivery of nanoprobes into the tumor parenchyma with minimal off-target distribution.

Authors
Yuan, H; Wilson, CM; Xia, J; Doyle, SL; Li, S; Fales, AM; Liu, Y; Ozaki, E; Mulfaul, K; Hanna, G; Palmer, GM; Wang, LV; Grant, GA; Vo-Dinh, T
MLA Citation
Yuan, H, Wilson, CM, Xia, J, Doyle, SL, Li, S, Fales, AM, Liu, Y, Ozaki, E, Mulfaul, K, Hanna, G, Palmer, GM, Wang, LV, Grant, GA, and Vo-Dinh, T. "Plasmonics-enhanced and optically modulated delivery of gold nanostars into brain tumor." Nanoscale 6.8 (April 21, 2014): 4078-4082.
PMID
24619405
Source
pubmed
Published In
Nanoscale
Volume
6
Issue
8
Publish Date
2014
Start Page
4078
End Page
4082
DOI
10.1039/c3nr06770j

Enhanced SPR Sensitivity with Nano-Micro-Ribbon Grating-an Exhaustive Simulation Mapping

In this study, we theoretically investigate the sensing potential of 2D nano- and micro-ribbon grating structuration on the surface of Kretschmann-based surface plasmon resonance (SPR) biosensors when they are employed for detection of biomolecular binding events. Numerical simulations were carried out by employing a model based on the hybridization of two classical methods, the Fourier modal method and the finite element method. Our calculations confirm the importance of light manipulation by means of structuration of the plasmonic thin film surfaces on the nano- and micro-scales. Not only does it highlight the geometric parameters that allow the sensitivity enhancement compared with the response of the conventional SPR biosensor based on a flat surface but also describes the transition from the regime where the propagating surface plasmon mode dominates to the regime where the localized surface plasmon mode dominates. An exhaustive mapping of the biosensing potential of the 2D nano- and micro-structured biosensors surface is presented, varying the structural parameters related to the ribbon grating dimensions, i.e., the widths and thicknesses. The nano- and micro-structuration also leads to the creation of regions on biosensor chips that are characterized by strongly enhanced electromagnetic (EM) fields. New opportunities for further improving the sensitivity are offered if localization of biomolecules can be carried out in these regions of high EM fields. The continuum of nano- and micro-ribbon structured biosensors described in this study should prove a valuable tool for developing sensitive and reliable 2D-structured plasmonic biosensors. © 2013 Springer Science+Business Media New York.

Authors
Chamtouri, M; Dhawan, A; Besbes, M; Moreau, J; Ghalila, H; Vo-Dinh, T; Canva, M
MLA Citation
Chamtouri, M, Dhawan, A, Besbes, M, Moreau, J, Ghalila, H, Vo-Dinh, T, and Canva, M. "Enhanced SPR Sensitivity with Nano-Micro-Ribbon Grating-an Exhaustive Simulation Mapping." Plasmonics 9.1 (February 1, 2014): 79-92.
Source
scopus
Published In
Plasmonics
Volume
9
Issue
1
Publish Date
2014
Start Page
79
End Page
92
DOI
10.1007/s11468-013-9600-4

Development of Hybrid Silver-Coated Gold Nanostars for Nonaggregated Surface-Enhanced Raman Scattering.

In the ongoing search for ever-brighter surface-enhanced Raman scattering (SERS) nanoprobes, gold nanostars (AuNSs) have emerged as one of the best geometries for producing SERS in a nonaggregated state. Despite their high enhancement factor, optical extinction from plasmon-matched nanoparticles can greatly attenuate the overall SERS intensity. Herein, we report the development of a new hybrid bimetallic NS-based platform that exhibits superior resonant SERS (SERRS) properties. In this new nanoplatform, coating AuNSs with a subtotal layer of silver (AuNS@Ag) can further increase their SERRS brightness by an order of magnitude when being interrogated by an off-resonant excitation source. Silica-encapsulated AuNS@Ag nanoprobes were injected intradermally into a rat pelt, where SERRS was readily detected with higher signal-to-noise than nanoprobes prepared from AuNS. Moreover, these off-resonance AuNS@Ag nanoprobes did not cause any gross photothermal damage to tissue, which was observed with the plasmon-matched AuNSs. This novel SERRS-active hybrid nanoprobe exhibits high SERRS brightness and offers promising properties for future applications in sensing and molecular imaging.

Authors
Fales, AM; Yuan, H; Vo-Dinh, T
MLA Citation
Fales, AM, Yuan, H, and Vo-Dinh, T. "Development of Hybrid Silver-Coated Gold Nanostars for Nonaggregated Surface-Enhanced Raman Scattering." The journal of physical chemistry. C, Nanomaterials and interfaces 118.7 (February 2014): 3708-3715.
PMID
24803974
Source
epmc
Published In
The Journal of Physical Chemistry C
Volume
118
Issue
7
Publish Date
2014
Start Page
3708
End Page
3715
DOI
10.1021/jp4091393

Optically enhanced blood-brain-barrier crossing of plasmonic-active nanoparticles in preclinical brain tumor animal models

Nanotechnology provides tremendous biomedical opportunities for cancer diagnosis, imaging, and therapy. In contrast to conventional chemotherapeutic agents where their actual target delivery cannot be easily imaged, integrating imaging and therapeutic properties into one platform facilitates the understanding of pharmacokinetic profiles, and enables monitoring of the therapeutic process in each individual. Such a concept dubbed "theranostics potentiates translational research and improves precision medicine. One particular challenging application of theranostics involves imaging and controlled delivery of nanoplatforms across blood-brain-barrier (BBB) into brain tissues. Typically, the BBB hinders paracellular flux of drug molecules into brain parenchyma. BBB disrupting agents (e.g. mannitol, focused ultrasound), however, suffer from poor spatial confinement. It has been a challenge to design a nanoplatform not only acts as a contrast agent but also improves the BBB permeation. In this study, we demonstrated the feasibility of plasmonic gold nanoparticles as both high-resolution optical contrast agent and focalized tumor BBB permeation-inducing agent. We specifically examined the microscopic distribution of nanoparticles in tumor brain animal models. We observed that most nanoparticles accumulated at the tumor periphery or perivascular spaces. Nanoparticles were present in both endothelial cells and interstitial matrices. This study also demonstrated a novel photothermal-induced BBB permeation. Fine-tuning the irradiating energy induced gentle disruption of the vascular integrity, causing short-term extravasation of nanomaterials but without hemorrhage. We conclude that our gold nanoparticles are a powerful biocompatible contrast agent capable of inducing focal BBB permeation, and therefore envision a strong potential of plasmonic gold nanoparticle in future brain tumor imaging and therapy.

Authors
Yuan, H; Wilson, CM; Li, S; Fales, AM; Liu, Y; Grant, G; Vo-Dinh, T
MLA Citation
Yuan, H, Wilson, CM, Li, S, Fales, AM, Liu, Y, Grant, G, and Vo-Dinh, T. "Optically enhanced blood-brain-barrier crossing of plasmonic-active nanoparticles in preclinical brain tumor animal models." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 8935 (January 1, 2014).
Source
scopus
Published In
Proceedings of SPIE
Volume
8935
Publish Date
2014
DOI
10.1117/12.2040960

Plasmonic gold nanostar for biomedical sensing

Cancer has become one of most significant death reasons and causes approximately 7.9 million human deaths worldwide each year. The challenge to detect cancer at an early stage makes cancer-related biomarkers sensing attract more and more research interest and efforts. Surface-enhanced Raman scattering (SERS) provides a promising method for various biomarkers (DNA, RNA, protein, et al.) detection due to its high sensitivity, specificity and capability for multiple analytes detection. Raman spectroscopy is a non-destructive photon-scattering technique, which provides molecule-specific information on molecular vibrational energy levels. SERS takes advantage of plasmonic effects and can enhance Raman signal up to 1015 at "hot spots". Due to its excellent sensitivity, SERS has been capable of achieving single-molecule detection limit. Local pH environment has been identified to be a potential biomarker for cancer diagnosis since solid cancer contains highly acidic environments. A near-infrared (NIR) SERS nanoprobe based on gold nanostars for pH sensing is developed for future cancer detection. Near-infrared (NIR) light is more suitable for in vivo applications because of its low attenuation rate and tissue auto fluorescence. SERS spectrum of pH reporter under various pH environments is monitored and used for pH sensing. Furthermore, density functional theory (DFT) calculation is performed to investigate Raman spectra changes with pH at the molecular level. The study demonstrates that SERS is a sensitive tool to monitor minor molecular structural changes due to local pH environment for cancer detection. © 2014 SPIE.

Authors
Liu, Y; Yuan, H; Fales, AM; Vo-Dinh, T
MLA Citation
Liu, Y, Yuan, H, Fales, AM, and Vo-Dinh, T. "Plasmonic gold nanostar for biomedical sensing." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 8957 (January 1, 2014).
Source
scopus
Published In
Proceedings of SPIE
Volume
8957
Publish Date
2014
DOI
10.1117/12.2040636

Multiplex detection of disease biomarkers using SERS molecular sentinel-on-chip Multiplex Platforms in Diagnostics and Bioanalytics

Developing techniques for multiplex detection of disease biomarkers is important for clinical diagnosis. In this work, we have demonstrated for the first time the feasibility of multiplex detection of genetic disease biomarkers using the surface-enhanced Raman scattering (SERS)-based molecular sentinel-on-chip (MSC) diagnostic technology. The molecular sentinel (MS) sensing mechanism is based upon the decrease of SERS intensity when Raman labels tagged at 3′-ends of MS nanoprobes are physically displaced from the nanowave chip's surface upon DNA hybridization. The use of bimetallic layer (silver and gold) for the nanowave fabrication was investigated. SERS measurements were performed immediately following a single hybridization reaction between the target single-stranded DNA sequences and the complementary MS nanoprobes immobilized on the nanowave chip without requiring target labeling (i.e., label-free), secondary hybridization, or post-hybridization washing, thus shortening the assay time and reducing cost. Two nucleic acid transcripts, interferon alpha-inducible protein 27 and interferon-induced protein 44-like, are used as model systems for the multiplex detection concept demonstration. These two genes are well known for their critical role in host immune response to viral infection and can be used as molecular signature for viral infection diagnosis. The results indicate the potential of the MSC technology for nucleic acid biomarker multiplex detection. [Figure not available: see fulltext.] © 2014 Springer-Verlag Berlin Heidelberg.

Authors
Ngo, HT; Wang, HN; Burke, T; Ginsburg, GS; Vo-Dinh, T
MLA Citation
Ngo, HT, Wang, HN, Burke, T, Ginsburg, GS, and Vo-Dinh, T. "Multiplex detection of disease biomarkers using SERS molecular sentinel-on-chip Multiplex Platforms in Diagnostics and Bioanalytics." Analytical and Bioanalytical Chemistry 406.14 (January 1, 2014): 3335-3344.
Source
scopus
Published In
Analytical and Bioanalytical Chemistry
Volume
406
Issue
14
Publish Date
2014
Start Page
3335
End Page
3344
DOI
10.1007/s00216-014-7648-4

Micovascular integration into porous polyHEMA scaffold

Surface-enhanced Raman scattering (SERS) spectroscopy can be a useful tool in regard to disease diagnosis and prevention. Advantage of SERS over conventional Raman spectroscopy is its significantly increased signal (up to factor of 106-108) which allows detection of trace amounts of substances in the sample. So far, this technique is successfully used for analysis of food, pieces of art and various biochemical/biomedical samples. In this work, we survey the possibility of applying SERS spectroscopy for detection of trace components in urinary deposits. Early discovery together with the identification of the exact chemical composition of urinary sediments could be crucial for taking appropriate preventive measures that inhibit kidney stone formation or growth processes. In this initial study, SERS spectra (excitation wavelength - 1064 nm) of main components of urinary deposits (calcium oxalate, uric acid, cystine, etc.) were recorded by using silver (Ag) colloid. Spectra of 10-3-10-5 M solutions were obtained. While no/small Raman signal was detected without the Ag colloid, characteristic peaks of the substances could be clearly separated in the SERS spectra. This suggests that even small amounts of the components could be detected and taken into account while determining the type of kidney stone forming in the urinary system. We found for the first time that trace amounts of components constituting urinary deposits could be detected by SERS spectroscopy. In the future study, the analysis of centrifuged urine samples will be carried out. © 2014 SPIE.

Authors
Cho, EH; Boico, A; Wisniewski, NA; Gant, R; Helton, KL; Brown, NL; Register, JK; Vo-Dinh, T; Schroeder, T; Klitzman, B
MLA Citation
Cho, EH, Boico, A, Wisniewski, NA, Gant, R, Helton, KL, Brown, NL, Register, JK, Vo-Dinh, T, Schroeder, T, and Klitzman, B. "Micovascular integration into porous polyHEMA scaffold." January 1, 2014.
Source
scopus
Volume
8958
Publish Date
2014
DOI
10.1117/12.2037950

Direct analysis of traditional Chinese medicines using surface-enhanced raman scattering (SERS)

© 2014 John Wiley & Sons, Ltd.Surface-Enhanced Raman Scattering (SERS) spectrometry provides an excellent tool to characterize chemical constituents in Traditional Chinese Medicines (TCMs) without requiring separation and extraction procedures. This study involved the use of SERS to analyze two TCMs, namely Coptis chinensis and Phellodendron amurense, and their main active constituent, berberine. Using silver nanospheres as SERS-active probes, the decoctions of two raw TCMs and their counterfeits were analyzed. Density functional theory (DFT) was used to calculate the expected Raman spectrum of berberine, and liquid chromatography- mass spectrometry (LC-MS) was used as a comparative technique to quantify the amount of berberine in the samples. The results of the SERS measurements were consistent with the results of DFT calculations and LCMS analyses. To our knowledge, this is the first time that the potential of SERS was demonstrated as a sensitive, rapid, and non-destructive method to qualitatively and quantitatively analyze the active constituents in raw TCM products.

Authors
Zhao, J; Liu, Y; Fales, AM; Register, J; Yuan, H; Vo-Dinh, T
MLA Citation
Zhao, J, Liu, Y, Fales, AM, Register, J, Yuan, H, and Vo-Dinh, T. "Direct analysis of traditional Chinese medicines using surface-enhanced raman scattering (SERS)." Drug Testing and Analysis 6.10 (January 1, 2014): 1063-1068.
Source
scopus
Published In
Drug Testing and Analysis
Volume
6
Issue
10
Publish Date
2014
Start Page
1063
End Page
1068
DOI
10.1002/dta.1612

Quintuple-modality (SERS-MRI-CT-TPL-PTT) plasmonic nanoprobe for theranostics.

A unique quintuple-modality theranostic nanoprobe (QMT) is developed with gold nanostars for surface-enhanced Raman scattering (SERS), magnetic resonance imaging (MRI), computed tomography (CT), two-photon luminescence (TPL) imaging and photothermal therapy (PTT). The synthesized gold nanostars were tagged with a SERS reporter and linked with an MRI contrast agent Gd(3+). In vitro experiments demonstrated the developed QMT nanoprobe to be a potential theranostic agent for future biomedical applications.

Authors
Liu, Y; Chang, Z; Yuan, H; Fales, AM; Vo-Dinh, T
MLA Citation
Liu, Y, Chang, Z, Yuan, H, Fales, AM, and Vo-Dinh, T. "Quintuple-modality (SERS-MRI-CT-TPL-PTT) plasmonic nanoprobe for theranostics." Nanoscale 5.24 (December 21, 2013): 12126-12131.
PMID
24162005
Source
pubmed
Published In
Nanoscale
Volume
5
Issue
24
Publish Date
2013
Start Page
12126
End Page
12131
DOI
10.1039/c3nr03762b

Plasmonic nanoprobes: from chemical sensing to medical diagnostics and therapy.

This article provides an overview of the development and applications of plasmonics-active nanoprobes in our laboratory for chemical sensing, medical diagnostics and therapy. Molecular Sentinel nanoprobes provide a unique tool for DNA/RNA biomarker detection both in a homogeneous solution or on a chip platform for medical diagnostics. The possibility of combining spectral selectivity and high sensitivity of the surface-enhanced Raman scattering (SERS) process with the inherent molecular specificity of nanoprobes provides an important multiplex diagnostic modality. Gold nanostars can provide an excellent multi-modality platform, combining two-photon luminescence with photothermal therapy as well as Raman imaging with photodynamic therapy. Several examples of optical detection using SERS and photonics-based treatments are presented to illustrate the usefulness and potential of the plasmonic nanoprobes for theranostics, which seamlessly combines diagnostics and therapy.

Authors
Vo-Dinh, T; Fales, AM; Griffin, GD; Khoury, CG; Liu, Y; Ngo, H; Norton, SJ; Register, JK; Wang, H-N; Yuan, H
MLA Citation
Vo-Dinh, T, Fales, AM, Griffin, GD, Khoury, CG, Liu, Y, Ngo, H, Norton, SJ, Register, JK, Wang, H-N, and Yuan, H. "Plasmonic nanoprobes: from chemical sensing to medical diagnostics and therapy." Nanoscale 5.21 (November 7, 2013): 10127-10140. (Review)
PMID
24056945
Source
pubmed
Published In
Nanoscale
Volume
5
Issue
21
Publish Date
2013
Start Page
10127
End Page
10140
DOI
10.1039/c3nr03633b

Surface-enhanced Raman scattering molecular sentinel nanoprobes for viral infection diagnostics.

In this paper, we describe a surface-enhanced Raman scattering (SERS)-based detection approach, referred to as "molecular sentinel" (MS) plasmonic nanoprobes, to detect an RNA target related to viral infection. The MS method is essentially a label-free technique incorporating the SERS effect modulation scheme associated with silver nanoparticles and Raman dye-labeled DNA hairpin probes. Hybridization with target sequences opens the hairpin and spatially separates the Raman label from the silver surface thus reducing the SERS signal of the label. Herein, we have developed a MS nanoprobe to detect the human radical S-adenosyl methionine domain containing 2 (RSAD2) RNA target as a model system for method demonstration. The human RSAD2 gene has recently emerged as a novel host-response biomarker for diagnosis of respiratory infections. Our results showed that the RSAD2 MS nanoprobes exhibits high specificity and can detect as low as 1 nM target sequences. With the use of a portable Raman spectrometer and total RNA samples, we have also demonstrated for the first time the potential of the MS nanoprobe technology for detection of host-response RNA biomarkers for infectious disease diagnostics.

Authors
Wang, H-N; Fales, AM; Zaas, AK; Woods, CW; Burke, T; Ginsburg, GS; Vo-Dinh, T
MLA Citation
Wang, H-N, Fales, AM, Zaas, AK, Woods, CW, Burke, T, Ginsburg, GS, and Vo-Dinh, T. "Surface-enhanced Raman scattering molecular sentinel nanoprobes for viral infection diagnostics." Anal Chim Acta 786 (July 5, 2013): 153-158.
PMID
23790305
Source
pubmed
Published In
Analytica Chimica Acta
Volume
786
Publish Date
2013
Start Page
153
End Page
158
DOI
10.1016/j.aca.2013.05.017

Label-free DNA biosensor based on SERS Molecular Sentinel on Nanowave chip.

Development of a rapid, cost-effective, label-free biosensor for DNA detection is important for many applications in clinical diagnosis, homeland defense, and environment monitoring. A unique label-free DNA biosensor based on Molecular Sentinel (MS) immobilized on a plasmonic 'Nanowave' chip, which is also referred to as a metal film over nanosphere (MFON), is presented. Its sensing mechanism is based upon the decrease of the surface-enhanced Raman scattering (SERS) intensity when Raman label tagged at one end of MS is physically separated from the MFON's surface upon DNA hybridization. This method is label-free as the target does not have to be labeled. The MFON fabrication is relatively simple and low-cost with high reproducibility based on depositing a thin shell of gold over close-packed arrays of nanospheres. The sensing process involves a single hybridization step between the DNA target sequences and the complementary MS probes on the Nanowave chip without requiring secondary hybridization or posthybridization washing, thus resulting in rapid assay time and low reagent usage. The usefulness and potential application of the biosensor for medical diagnostics is demonstrated by detecting the human radical S-adenosyl methionine domain containing 2 (RSAD2) gene, a common inflammation biomarker.

Authors
Ngo, HT; Wang, H-N; Fales, AM; Vo-Dinh, T
MLA Citation
Ngo, HT, Wang, H-N, Fales, AM, and Vo-Dinh, T. "Label-free DNA biosensor based on SERS Molecular Sentinel on Nanowave chip." Anal Chem 85.13 (July 2, 2013): 6378-6383.
PMID
23718777
Source
pubmed
Published In
Analytical Chemistry
Volume
85
Issue
13
Publish Date
2013
Start Page
6378
End Page
6383
DOI
10.1021/ac400763c

Plasmonic nanoprobes for intracellular sensing and imaging.

Recent advances in integrating nanotechnology and optical microscopy offer great potential in intracellular applications with improved molecular information and higher resolution. Continuous efforts in designing nanoparticles with strong and tunable plasmon resonance have led to new developments in biosensing and bioimaging, using surface-enhanced Raman scattering and two-photon photoluminescence. We provide an overview of the nanoprobe design updates, such as controlling the nanoparticle shape for optimal plasmon peak position; optical sensing and imaging strategies for intracellular nanoparticle detection; and addressing practical challenges in cellular applications of nanoprobes, including the use of targeting agents and control of nanoparticle aggregation.

Authors
Yuan, H; Register, JK; Wang, H-N; Fales, AM; Liu, Y; Vo-Dinh, T
MLA Citation
Yuan, H, Register, JK, Wang, H-N, Fales, AM, Liu, Y, and Vo-Dinh, T. "Plasmonic nanoprobes for intracellular sensing and imaging." Anal Bioanal Chem 405.19 (July 2013): 6165-6180. (Review)
PMID
23665636
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
405
Issue
19
Publish Date
2013
Start Page
6165
End Page
6180
DOI
10.1007/s00216-013-6975-1

Cell-penetrating peptide enhanced intracellular Raman imaging and photodynamic therapy.

We present the application of a theranostic system combining Raman imaging and the photodynamic therapy (PDT) effect. The theranostic nanoplatform was created by loading the photosensitizer, protoporphyrin IX, onto a Raman-labeled gold nanostar. A cell-penetrating peptide, TAT, enhanced intracellular accumulation of the nanoparticles in order to improve their delivery and efficacy. The plasmonic gold nanostar platform was designed to increase the Raman signal via the surface-enhanced resonance Raman scattering (SERRS) effect. Theranostic SERS imaging and photodynamic therapy using this construct were demonstrated on BT-549 breast cancer cells. The TAT peptide allowed for effective Raman imaging and photosensitization with the nanoparticle construct after a 1 h incubation period. In the absence of the TAT peptide, nanoparticle accumulation in the cells was not sufficient to be observed by Raman imaging or to produce any photosensitization effect after this short incubation period. There was no cytotoxic effect observed after nanoparticle incubation, prior to light activation of the photosensitizer. This report shows the first application of combined SERS imaging and photosensitization from a theranostic nanoparticle construct.

Authors
Fales, AM; Yuan, H; Vo-Dinh, T
MLA Citation
Fales, AM, Yuan, H, and Vo-Dinh, T. "Cell-penetrating peptide enhanced intracellular Raman imaging and photodynamic therapy." Mol Pharm 10.6 (June 3, 2013): 2291-2298.
PMID
23659475
Source
pubmed
Published In
Molecular Pharmaceutics
Volume
10
Issue
6
Publish Date
2013
Start Page
2291
End Page
2298
DOI
10.1021/mp300634b

Molecular sentinel-on-chip for SERS-based biosensing.

The development of DNA detection techniques on large-area plasmonics-active platforms is critical for many medical applications such as high-throughput screening, medical diagnosis and systems biology research. Here, we report for the first time a unique "molecular sentinel-on-chip" (MSC) technology for surface-enhanced Raman scattering (SERS)-based DNA detection. This unique approach allows label-free detection of DNA molecules on chips developed on a wafer scale using large area nanofabrication methodologies. To develop plasmonics-active biosensing platforms in a repeatable and reproducible manner, we employed a combination of deep UV lithography, atomic layer deposition, and metal deposition to fabricate triangular-shaped nanowire (TSNW) arrays having controlled sub-10 nm gap nanostructures over an entire 6 inch wafer. The detection of a DNA sequence of the Ki-67 gene, a critical breast cancer biomarker, on the TSNW substrate illustrates the usefulness and potential of the MSC technology as a novel SERS-based DNA detection method.

Authors
Wang, H-N; Dhawan, A; Du, Y; Batchelor, D; Leonard, DN; Misra, V; Vo-Dinh, T
MLA Citation
Wang, H-N, Dhawan, A, Du, Y, Batchelor, D, Leonard, DN, Misra, V, and Vo-Dinh, T. "Molecular sentinel-on-chip for SERS-based biosensing." Phys Chem Chem Phys 15.16 (April 28, 2013): 6008-6015.
PMID
23493773
Source
pubmed
Published In
Physical Chemistry Chemical Physics
Volume
15
Issue
16
Publish Date
2013
Start Page
6008
End Page
6015
DOI
10.1039/c3cp00076a

Quantitative surface-enhanced resonant Raman scattering multiplexing of biocompatible gold nanostars for in vitro and ex vivo detection.

Surface-enhanced Raman scattering (SERS)-active plasmonic nanomaterials have become a promising agent for molecular imaging and multiplex detection. To produce strong SERS intensity while retaining the nonaggregated state and biocompatibility needed for bioapplications, we integrated near-infrared (NIR) responsive plasmonic gold nanostars with resonant dyes for resonant SERS (SERRS). The SERRS on nanostars was several orders of magnitude greater than signals from SERRS on nanospheres and nonresonant SERS on nanostars. For the first time, we demonstrated quantitative multiplex detection using four unique nanostar SERRS probes in both in vitro solutions and ex vivo tissue samples under NIR excitation. With further optimization, in vivo tracking of multiple SERRS probes is possible.

Authors
Yuan, H; Liu, Y; Fales, AM; Li, YL; Liu, J; Vo-Dinh, T
MLA Citation
Yuan, H, Liu, Y, Fales, AM, Li, YL, Liu, J, and Vo-Dinh, T. "Quantitative surface-enhanced resonant Raman scattering multiplexing of biocompatible gold nanostars for in vitro and ex vivo detection." Anal Chem 85.1 (January 2, 2013): 208-212.
PMID
23194068
Source
pubmed
Published In
Analytical Chemistry
Volume
85
Issue
1
Publish Date
2013
Start Page
208
End Page
212
DOI
10.1021/ac302510g

Spectroscopic and vibrational analysis of the methoxypsoralen system: A comparative experimental and theoretical study

Raman spectra measurements and density functional theory (DFT) calculations were performed to investigate three psoralens: 5-amino-8-methoxypsoralen (5-A-8-MOP), 5-methoxypsoralen (5-MOP) and 8-methoxypsoralen (8-MOP) with the aim of differentiating these similar bioactive molecules. The Raman spectra were recorded in the region 300-3500 cm-1. All three psoralens were found to have similar Raman spectrum in the region 1500-1650 cm-1. 5-A-8-MOP can be easily differentiated from 5-MOP or 8-MOP based on the Raman spectrum. The Raman spectrum differences at 651 and 795 cm-1 can be used to identify 5-MOP from 8-MOP. The theoretically computed vibrational frequencies and relative peak intensities were compared with experimental data. DFT calculations using the B3LYP method and 6-311++G(d,p) basis set were found to yield results that are very comparable to experimental Raman spectra. Detailed vibrational assignments were performed with DFT calculations and the potential energy distribution (PED) obtained from the Vibrational Energy Distribution Analysis (VEDA) program. © 2012 Elsevier B.V. All rights reserved.

Authors
Liu, Y; Yuan, H; Vo-Dinh, T
MLA Citation
Liu, Y, Yuan, H, and Vo-Dinh, T. "Spectroscopic and vibrational analysis of the methoxypsoralen system: A comparative experimental and theoretical study." Journal of Molecular Structure 1035 (2013): 13-18.
Source
scival
Published In
Journal of Molecular Structure
Volume
1035
Publish Date
2013
Start Page
13
End Page
18
DOI
10.1016/j.molstruc.2012.08.047

Spectral characterization and intracellular detection of Surface-Enhanced Raman Scattering (SERS)-encoded plasmonic gold nanostars

Plasmonic gold nanostars offer a new platform for surface-enhanced Raman scattering (SERS). However, due to the presence of organic surfactant on the nanoparticles, SERS characterization and application of nanostar ensembles in solution have been challenging. Here, we applied our newly developed surfactant-free nanostars for SERS characterization and application. The SERS enhancement factors (EF) of silver spheres, gold spheres and nanostars of similar sizes and concentration were compared. Under 785 nm excitation, nanostars and silver spheres have similar EF, and both are much stronger than gold spheres. Having plasmon matching the incident energy and multiple 'hot spots' on the branches bring forth strong SERS response without the need to aggregate. Intracellular detection of silica-coated SERS-encoded nanostars was also demonstrated in breast cancer cells. The non-aggregated field enhancement makes the gold nanostar ensemble a promising agent for SERS bioapplications. Copyright © 2012 John Wiley & Sons, Ltd.

Authors
Yuan, H; Fales, AM; Khoury, CG; Liu, J; Vo-Dinh, T
MLA Citation
Yuan, H, Fales, AM, Khoury, CG, Liu, J, and Vo-Dinh, T. "Spectral characterization and intracellular detection of Surface-Enhanced Raman Scattering (SERS)-encoded plasmonic gold nanostars." Journal of Raman Spectroscopy 44.2 (2013): 234-239.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
44
Issue
2
Publish Date
2013
Start Page
234
End Page
239
DOI
10.1002/jrs.4172

pH-sensing nanostar probe using surface-enhanced Raman scattering (SERS): Theoretical and experimental studies

Local pH environment has been considered to be a potential biomarker for tumor diagnosis because solid tumors contain highly acidic environments. A pH-sensing nanoprobe based on surface-enhanced Raman scattering (SERS) using nanostars under near-infrared excitation has been developed for potential biomedical applications. To theoretically investigate the effect of protonation state on SERS spectra of p-mercaptobenzoic acid (pMBA), we used the density functional theory (DFT) with the B3LYP functional to calculate Raman vibrational spectra of pMBA-Au/Ag complex in both protonated and deprotonated states. Vibrational spectral bands were assigned with DFT calculation and used to investigate SERS spectral changes observed from experiment when varying pH value between five and nine. The SERS peak position of pMBA at ~1580cm-1 was identified to be a novel pH-sensing index, which has small but noticeable downshift with pH increase. This phenomenon is confirmed and well-explained with theoretical simulation. The study demonstrates that SERS is a sensitive tool to monitor minor structural changes due to local pH environment, and DFT calculations can be used to investigate Raman spectra changes associated with minor differences in molecular structure. © 2013 John Wiley & Sons, Ltd.

Authors
Liu, Y; Yuan, H; Fales, AM; Vo-Dinh, T
MLA Citation
Liu, Y, Yuan, H, Fales, AM, and Vo-Dinh, T. "pH-sensing nanostar probe using surface-enhanced Raman scattering (SERS): Theoretical and experimental studies." Journal of Raman Spectroscopy (2013).
Source
scival
Published In
Journal of Raman Spectroscopy
Publish Date
2013
DOI
10.1002/jrs.4302

Progress in Biomedical Optics and Imaging - Proceedings of SPIE: Introduction

This PDF file contains the front matter associated with SPIE Proceedings Volume 8572, including the Title Page, Copyright Information, Table of Contents, and the Conference Committee listing. © 2013 Copyright SPIE.

Authors
Mahadevan-Jansen, A; Vo-Dinh, T; Grundfest, WS
MLA Citation
Mahadevan-Jansen, A, Vo-Dinh, T, and Grundfest, WS. "Progress in Biomedical Optics and Imaging - Proceedings of SPIE: Introduction." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 8572 (2013): ix-.
Source
scival
Published In
Proceedings of SPIE
Volume
8572
Publish Date
2013
Start Page
ix
DOI
10.1117/12.2024923

PH-sensing nanostar probe using surface-enhanced Raman scattering (SERS): Theoretical and experimental studies

Local pH environment has been considered to be a potential biomarker for tumor diagnosis because solid tumors contain highly acidic environments. A pH-sensing nanoprobe based on surface-enhanced Raman scattering (SERS) using nanostars under near-infrared excitation has been developed for potential biomedical applications. To theoretically investigate the effect of protonation state on SERS spectra of p-mercaptobenzoic acid (pMBA), we used the density functional theory (DFT) with the B3LYP functional to calculate Raman vibrational spectra of pMBA-Au/Ag complex in both protonated and deprotonated states. Vibrational spectral bands were assigned with DFT calculation and used to investigate SERS spectral changes observed from experiment when varying pH value between five and nine. The SERS peak position of pMBA at ≃1580 cm -1 was identified to be a novel pH-sensing index, which has small but noticeable downshift with pH increase. This phenomenon is confirmed and well-explained with theoretical simulation. The study demonstrates that SERS is a sensitive tool to monitor minor structural changes due to local pH environment, and DFT calculations can be used to investigate Raman spectra changes associated with minor differences in molecular structure. © 2013 John Wiley & Sons, Ltd.

Authors
Liu, Y; Yuan, H; Fales, AM; Vo-Dinh, T
MLA Citation
Liu, Y, Yuan, H, Fales, AM, and Vo-Dinh, T. "PH-sensing nanostar probe using surface-enhanced Raman scattering (SERS): Theoretical and experimental studies." Journal of Raman Spectroscopy 44.7 (2013): 980-986.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
44
Issue
7
Publish Date
2013
Start Page
980
End Page
986
DOI
10.1002/jrs.4302

Enhanced SPR Sensitivity with Nano-Micro-Ribbon Grating-an Exhaustive Simulation Mapping

In this study, we theoretically investigate the sensing potential of 2D nano- and micro-ribbon grating structuration on the surface of Kretschmann-based surface plasmon resonance (SPR) biosensors when they are employed for detection of biomolecular binding events. Numerical simulations were carried out by employing a model based on the hybridization of two classical methods, the Fourier modal method and the finite element method. Our calculations confirm the importance of light manipulation by means of structuration of the plasmonic thin film surfaces on the nano- and micro-scales. Not only does it highlight the geometric parameters that allow the sensitivity enhancement compared with the response of the conventional SPR biosensor based on a flat surface but also describes the transition from the regime where the propagating surface plasmon mode dominates to the regime where the localized surface plasmon mode dominates. An exhaustive mapping of the biosensing potential of the 2D nano- and micro-structured biosensors surface is presented, varying the structural parameters related to the ribbon grating dimensions, i.e., the widths and thicknesses. The nano- and micro-structuration also leads to the creation of regions on biosensor chips that are characterized by strongly enhanced electromagnetic (EM) fields. New opportunities for further improving the sensitivity are offered if localization of biomolecules can be carried out in these regions of high EM fields. The continuum of nano- and micro-ribbon structured biosensors described in this study should prove a valuable tool for developing sensitive and reliable 2D-structured plasmonic biosensors. © 2013 Springer Science+Business Media New York.

Authors
Chamtouri, M; Dhawan, A; Besbes, M; Moreau, J; Ghalila, H; Vo-Dinh, T; Canva, M
MLA Citation
Chamtouri, M, Dhawan, A, Besbes, M, Moreau, J, Ghalila, H, Vo-Dinh, T, and Canva, M. "Enhanced SPR Sensitivity with Nano-Micro-Ribbon Grating-an Exhaustive Simulation Mapping." Plasmonics (2013): 1-14.
Source
scival
Published In
Plasmonics
Publish Date
2013
Start Page
1
End Page
14
DOI
10.1007/s11468-013-9600-4

Plasmonic gold nanostars: A potential agent for molecular imaging and cancer therapy

Gold nanostars, with tunable plasmon in the near infrared tissue optic window, generate intense two-photon photoluminescence capable of in vitro cell labeling and in vivo particle tracking. Efficient photothermal ablation therapy is also demonstrated. © 2011 Optical Society of America.

Authors
Yuan, H; Khoury, C; Fales, A; Wilson, C; Grant, G; Vo-Dinh, T
MLA Citation
Yuan, H, Khoury, C, Fales, A, Wilson, C, Grant, G, and Vo-Dinh, T. "Plasmonic gold nanostars: A potential agent for molecular imaging and cancer therapy." Biomedical Optics, BIOMED 2012 (December 1, 2012).
Source
scopus
Published In
Biomedical Optics, BIOMED 2012
Publish Date
2012

Angle-dependent resonance of localized and propagating surface plasmons in microhole arrays for enhanced biosensing.

The presence of microhole arrays in thin Au films is suited for the excitation of localized and propagating surface plasmon (SP) modes. Conditions can be established to excite a resonance between the localized and propagating SP modes, which further enhanced the local electromagnetic (EM) field. The co-excitation of localized and propagating SP modes depends on the angle of incidence (θ(exc)) and refractive index of the solution interrogated. As a consequence of the enhanced EM field, enhanced sensitivity and an improved response for binding events by about a factor of 3 to 5 was observed with SPR sensors in the Kretschmann configuration for a set of experimental conditions (λ(SPR), θ(exc), and η). Thus, microhole arrays can improve sensing applications of SPR based on classical prism-based instrumentation and are suited for SP-coupled spectroscopic techniques.

Authors
Live, LS; Dhawan, A; Gibson, KF; Poirier-Richard, H-P; Graham, D; Canva, M; Vo-Dinh, T; Masson, J-F
MLA Citation
Live, LS, Dhawan, A, Gibson, KF, Poirier-Richard, H-P, Graham, D, Canva, M, Vo-Dinh, T, and Masson, J-F. "Angle-dependent resonance of localized and propagating surface plasmons in microhole arrays for enhanced biosensing." Anal Bioanal Chem 404.10 (December 2012): 2859-2868.
PMID
22760504
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
404
Issue
10
Publish Date
2012
Start Page
2859
End Page
2868
DOI
10.1007/s00216-012-6195-0

Direct optical imaging of graphene in vitro by nonlinear femtosecond laser spectral reshaping.

Nonlinear optical microscopy, based on femtosecond laser spectral reshaping, characterized and imaged graphene samples made from different methods, both on slides and in a biological environment. This technique clearly discriminates between graphene flakes with different numbers of layers and reveals the distinct nonlinear optical properties of reduced graphene oxide as compared to mechanically exfoliated or chemical vapor deposition grown graphene. The nonlinearity makes it applicable to scattering samples (such as tissue) as opposed to previous methods, such as transmission. This was demonstrated by high-resolution imaging of breast cancer cells incubated with graphene flakes.

Authors
Li, B; Cheng, Y; Liu, J; Yi, C; Brown, AS; Yuan, H; Vo-Dinh, T; Fischer, MC; Warren, WS
MLA Citation
Li, B, Cheng, Y, Liu, J, Yi, C, Brown, AS, Yuan, H, Vo-Dinh, T, Fischer, MC, and Warren, WS. "Direct optical imaging of graphene in vitro by nonlinear femtosecond laser spectral reshaping." Nano Lett 12.11 (November 14, 2012): 5936-5940.
PMID
23101475
Source
pubmed
Published In
Nano Letters
Volume
12
Issue
11
Publish Date
2012
Start Page
5936
End Page
5940
DOI
10.1021/nl303358p

In vivo particle tracking and photothermal ablation using plasmon-resonant gold nanostars.

UNLABELLED: Gold nanostars offer unique plasmon properties that efficiently transduce photon energy into heat for photothermal therapy. Nanostars, with their small core size and multiple long thin branches, exhibit high absorption cross-sections that are tunable in the near-infrared region with relatively low scattering effect, making them efficient photothermal transducers. Here, we demonstrate particle tracking and photothermal ablation both in vitro and in vivo. Using SKBR3 breast cancer cells incubated with bare nanostars, we observed photothermal ablation within 5 minutes of irradiation (980-nm continuous-wave laser, 15 W/cm2). On a mouse injected systemically with PEGylated nanostars for 2 days, extravasation of nanostars was observed and localized photothermal ablation was demonstrated on a dorsal window chamber within 10 minutes of irradiation (785-nm continuous-wave laser, 1.1 W/cm2). These preliminary results of plasmon-enhanced localized hyperthermia are encouraging and have illustrated the potential of gold nanostars as efficient photothermal agents in cancer therapy. FROM THE CLINICAL EDITOR: Gold nanostars are tunable in the near-infrared region with low scattering, thus enable photothermal therapy. Encouraging preliminary results of plasmon-enhanced localized hyperthermia both in vitro and in vivo demonstrate that Au nanostars may be efficient photothermal agents for cancer therapy.

Authors
Yuan, H; Khoury, CG; Wilson, CM; Grant, GA; Bennett, AJ; Vo-Dinh, T
MLA Citation
Yuan, H, Khoury, CG, Wilson, CM, Grant, GA, Bennett, AJ, and Vo-Dinh, T. "In vivo particle tracking and photothermal ablation using plasmon-resonant gold nanostars." Nanomedicine 8.8 (November 2012): 1355-1363.
PMID
22370335
Source
pubmed
Published In
Nanomedicine: Nanotechnology, Biology and Medicine
Volume
8
Issue
8
Publish Date
2012
Start Page
1355
End Page
1363
DOI
10.1016/j.nano.2012.02.005

Bimodal behavior and isobestic transition pathway in surface plasmon resonance sensing.

In traditional interpretation of surface plasmon resonance (SPR) sensing and imaging data, total surface coverage of adsorbed or deposited chemical and biological molecules is generally assumed. This homogenous assumption leads to the modeling of monomodal propagation of plasmons on the surface of the metallic film corresponding to a certain relative permittivity and thickness of the medium-such as molecular thin film-next to the metal. In actual SPR Imaging (SPRI) and SPR sensing situations, the plasmonics-active platforms (e.g., biochips) employed may capture the biomolecular targets as aggregates of different domain sizes on the surface of the thin metallic films. Indeed, such binding of target material always has a finite thickness and is characterized by aggregate lateral sizes possibly varying from tens of nanometers to hundreds of micrometers. This paper studies the propagation of surface plasmons in metallic films, with dielectric domain sizes varying within such ranges. Through rigorous coupled wave analysis (RCWA) calculations, it is indicated that when the domain size is small, only a single mode of propagation-i.e. 'monomodal' propagation behavior-occurs as indicated by only one dip in the angular reflectance curves associated with metallic film having a periodically structured array of molecules on its surface. On the other hand, as the domain size is increased, there is a transition from the 'monomodal propagation behavior' to the existence of a 'mixture of monomodal and bimodal propagation behavior', which changes to a purely 'bimodal behavior' after the size of the domain periodicity is increased beyond about ten micron. Such a transition pathway clearly exhibits isobestic points. The calculations presented in this paper can enable correct interpretation of experimental angular or spectral reflectance data.

Authors
Dhawan, A; Canva, M; Vo-Dinh, T
MLA Citation
Dhawan, A, Canva, M, and Vo-Dinh, T. "Bimodal behavior and isobestic transition pathway in surface plasmon resonance sensing." Opt Express 20.21 (October 8, 2012): 23630-23642.
PMID
23188328
Source
pubmed
Published In
Optics express
Volume
20
Issue
21
Publish Date
2012
Start Page
23630
End Page
23642

TAT peptide-functionalized gold nanostars: enhanced intracellular delivery and efficient NIR photothermal therapy using ultralow irradiance.

Gold nanoparticles have great potential in plasmonic photothermal therapy (photothermolysis), but their intracellular delivery and photothermolysis efficiency have yet to be optimized. We show that TAT-peptide-functionalized gold nanostars (NS) enter cells significantly more than bare or PEGylated NS. The cellular uptake mechanism involves actin-driven lipid raft-mediated macropinocytosis, where particles primarily accumulate in macropinosomes but may also leak out into the cytoplasm. After 4-h incubation of TAT-NS on BT549 breast cancer cells, photothermolysis was accomplished using 850 nm pulsed laser under 0.2 W/cm(2) irradiation, below the maximal permissible exposure of skin. These results demonstrate the enhanced intracellular delivery and efficient photothermolysis of TAT-NS, promising agents in cancer therapy.

Authors
Yuan, H; Fales, AM; Vo-Dinh, T
MLA Citation
Yuan, H, Fales, AM, and Vo-Dinh, T. "TAT peptide-functionalized gold nanostars: enhanced intracellular delivery and efficient NIR photothermal therapy using ultralow irradiance." J Am Chem Soc 134.28 (July 18, 2012): 11358-11361.
PMID
22734608
Source
pubmed
Published In
Journal of the American Chemical Society
Volume
134
Issue
28
Publish Date
2012
Start Page
11358
End Page
11361
DOI
10.1021/ja304180y

Multicontrast nonlinear optical microscopy with a compact and rapid pulse shaper.

Homodyne detection can dramatically enhance measurement sensitivity for weak signals. In nonlinear optical microscopy it can make accessible a range of novel, intrinsic, contrast like nonlinear absorption and nonlinear phase contrast. Here a compact and rapid pulse shaper is developed, implemented, and demonstrated for homodyne detection in nonlinear microscopy with high-repetition rate mode-locked femtosecond lasers. With this method we generate two-photon absorption (TPA) and self-phase modulation images of gold nanostars in biological samples. Simultaneous imaging of two-photon luminescence and TPA also enables us to produce two-photon quantum yield images.

Authors
Li, B; Claytor, KE; Yuan, H; Vo-Dinh, T; Warren, WS; Fischer, MC
MLA Citation
Li, B, Claytor, KE, Yuan, H, Vo-Dinh, T, Warren, WS, and Fischer, MC. "Multicontrast nonlinear optical microscopy with a compact and rapid pulse shaper." Opt Lett 37.13 (July 1, 2012): 2763-2765.
PMID
22743521
Source
pubmed
Published In
Optics Letters
Volume
37
Issue
13
Publish Date
2012
Start Page
2763
End Page
2765

The effect of reactive atypia/inflammation on the laser-induced fluorescence diagnosis of non-dysplastic Barrett's esophagus.

BACKGROUND AND OBJECTIVES: Differential Normalized Fluorescence (DNF) technique has been used to distinguish high-grade dysplasia from non-dysplastic Barrett's esophagus. This technology may assist gastroenterologists in targeting biopsies, reducing the number of biopsies using the standard protocol. In the presence of reactive atypia/inflammation, it becomes difficult for the pathologist to differentiate non-dysplastic Barrett's esophagus from Barrett's esophagus with low-grade dysplasia. Before DNF technique may be used to guide target biopsies, it is critical to know whether reactive atypia/inflammation in non-dysplastic Barrett's may result in false positives. This study was conducted to determine whether DNF technique is adversely affected by the presence of reactive atypia/inflammation in non-dysplastic Barrett's esophagus resulting in false positives. STUDY DESIGN/MATERIALS AND METHODS: Four hundred ten-nanometer laser light was used to induce autofluorescence of Barrett's mucosa in 49 patients. The clinical study included 37 males and 12 females. This was a blinded retrospective data analysis study. A total of 303 spectra were collected and matched to non-dysplastic Barrett's biopsy results. One hundred seventy-five spectra were collected from areas with a pathology of non-dysplastic Barrett's esophagus with reactive atypia/inflammation. One hundred twenty-eight spectra were collected from areas with non-dysplastic Barrett's esophagus without reactive changes/inflammation. The spectra were analyzed using the DNF Index at 480 nm and classified as positive or negative using the threshold of -0.75 × 10(-3). RESULTS: Using DNF technique, 92.6% of non-dysplastic samples with reactive atypia/inflammation were classified correctly (162/175). 92.2% of non-dysplastic samples without reactive atypia/inflammation were classified correctly (118/128). Comparing the ratios of false positives among the two sample groups, there was not a statistically significant difference between the two groups. CONCLUSION: Using DNF technique for classification of non-dysplastic Barrett's mucosa does not result in false-positive readings due to reactive atypia/inflammation. Target biopsies guided by DNF technique may drastically reduce the number of pinch biopsies using the standard biopsy protocol.

Authors
Panjehpour, M; Overholt, BF; Vo-Dinh, T; Coppola, D
MLA Citation
Panjehpour, M, Overholt, BF, Vo-Dinh, T, and Coppola, D. "The effect of reactive atypia/inflammation on the laser-induced fluorescence diagnosis of non-dysplastic Barrett's esophagus." Lasers Surg Med 44.5 (July 2012): 390-396.
PMID
22535652
Source
pubmed
Published In
Lasers in Surgery and Medicine
Volume
44
Issue
5
Publish Date
2012
Start Page
390
End Page
396
DOI
10.1002/lsm.22033

Gold nanostars: surfactant-free synthesis, 3D modelling, and two-photon photoluminescence imaging.

Understanding the control of the optical and plasmonic properties of unique nanosystems--gold nanostars--both experimentally and theoretically permits superior design and fabrication for biomedical applications. Here, we present a new, surfactant-free synthesis method of biocompatible gold nanostars with adjustable geometry such that the plasmon band can be tuned into the near-infrared region 'tissue diagnostic window', which is most suitable for in vivo imaging. Theoretical modelling was performed for multiple-branched 3D nanostars and yielded absorption spectra in good agreement with experimental results. The plasmon band shift was attributed to variations in branch aspect ratio, and the plasmon band intensifies with increasing branch number, branch length, and overall star size. Nanostars showed an extremely strong two-photon photoluminescence (TPL) process. The TPL imaging of wheat-germ agglutinin (WGA) functionalized nanostars on BT549 breast cancer cells and of PEGylated nanostars circulating in the vasculature, examined through a dorsal window chamber in vivo in laboratory mouse studies, demonstrated that gold nanostars can serve as an efficient contrast agent for biological imaging applications.

Authors
Yuan, H; Khoury, CG; Hwang, H; Wilson, CM; Grant, GA; Vo-Dinh, T
MLA Citation
Yuan, H, Khoury, CG, Hwang, H, Wilson, CM, Grant, GA, and Vo-Dinh, T. "Gold nanostars: surfactant-free synthesis, 3D modelling, and two-photon photoluminescence imaging." Nanotechnology 23.7 (February 24, 2012): 075102-.
PMID
22260928
Source
pubmed
Published In
Nanotechnology
Volume
23
Issue
7
Publish Date
2012
Start Page
075102
DOI
10.1088/0957-4484/23/7/075102

Spectral characterization and intracellular detection of Surface-Enhanced Raman Scattering (SERS)-encoded plasmonic gold nanostars

Plasmonic gold nanostars offer a new platform for surface-enhanced Raman scattering (SERS). However, due to the presence of organic surfactant on the nanoparticles, SERS characterization and application of nanostar ensembles in solution have been challenging. Here, we applied our newly developed surfactant-free nanostars for SERS characterization and application. The SERS enhancement factors (EF) of silver spheres, gold spheres and nanostars of similar sizes and concentration were compared. Under 785nm excitation, nanostars and silver spheres have similar EF, and both are much stronger than gold spheres. Having plasmon matching the incident energy and multiple 'hot spots' on the branches bring forth strong SERS response without the need to aggregate. Intracellular detection of silica-coated SERS-encoded nanostars was also demonstrated in breast cancer cells. The non-aggregated field enhancement makes the gold nanostar ensemble a promising agent for SERS bioapplications. © 2012 John Wiley & Sons, Ltd.

Authors
Yuan, H; Fales, AM; Khoury, CG; Liu, J; Vo-Dinh, T
MLA Citation
Yuan, H, Fales, AM, Khoury, CG, Liu, J, and Vo-Dinh, T. "Spectral characterization and intracellular detection of Surface-Enhanced Raman Scattering (SERS)-encoded plasmonic gold nanostars." Journal of Raman Spectroscopy (2012).
PMID
24839346
Source
scival
Published In
Journal of Raman Spectroscopy
Publish Date
2012
DOI
10.1002/jrs.4172

Plasmonic nanowave substrates for SERS: Fabrication and numerical analysis

The Nanowave substrate, comprising a close-packed array of nanospheres onto which a thin metal shell of silver or gold is deposited, was first fabricated in our laboratory in 1984 and used as a surface-enhanced Raman scattering (SERS)-active substrate for the sensitive and reproducible detection of analytes. More than twenty-five years after the first experimental demonstration of the effectiveness of this substrate, numerical simulations are sufficiently powerful and versatile to mimic this geometry in three-dimensional space and confirm the experimentally measured plasmonic behavior at the substrate’s surface. The study confirms that an in-plane polarized incident plane wave generates strong enhancements in the interstitial spaces between individual metal-coated nanospheres, thus producing closely packed arrays of hot spots underlining the strong SERS effect of the Nanowave substrate structures. The surface-averaged SERS enhancement exhibited by the Nanowaves was evaluated and compared for different metal thicknesses. The effect of structural confinement on the plasmonic behavior of the Nanowave structure was investigated by varying the structural confinement of the substrate in the plane parallel to the incident excitation. The Nanowave is an inexpensive, reproducible, and effective plasmonics-active substrate that has the potential to be used for SERS studies requiring high detection sensitivity. © 2012 American Chemical Society.

Authors
Khoury, CG; Vo-Dinh, T
MLA Citation
Khoury, CG, and Vo-Dinh, T. "Plasmonic nanowave substrates for SERS: Fabrication and numerical analysis." Journal of Physical Chemistry C 116.13 (2012): 7534-7545.
PMID
24839506
Source
scival
Published In
The Journal of Physical Chemistry C
Volume
116
Issue
13
Publish Date
2012
Start Page
7534
End Page
7545
DOI
10.1021/jp2120669

Imaging a spatially confined photoacoustic source defined by a distribution of plasmonic nanoparticles

This paper describes the use of plasmonic nanoparticles in photoacoustic imaging. When acoustic waves are generated by thermoacoustic expansion in the fluid medium surrounding a distribution of these particles and the acoustic signals are recorded over a planar aperture, a bandlimited image of this distribution can be reconstructed. It is shown that the accessible portion of the three-dimensional spatial Fourier transform of the unknown source distribution is a spherical shell in k-space, with the core representing missing low-frequency Fourier components of the source density. When the source arises from an isolated distribution of nanoparticles, the iterative Gerchberg-Papoulis procedure can be applied to recover the low-frequency Fourier components. It is shown that this version of the photoacoustic source reconstruction problem is well suited for the use of this procedure. In this way, the fidelity of the image of the photoacoustic-generated source defined by the particle concentration can be enhanced. The procedure is illustrated using simulated data derived from a hypothetical source distribution. © 2012 American Institute of Physics.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Imaging a spatially confined photoacoustic source defined by a distribution of plasmonic nanoparticles." Journal of Applied Physics 111.9 (2012).
Source
scival
Published In
Journal of Applied Physics
Volume
111
Issue
9
Publish Date
2012
DOI
10.1063/1.4709394

Assessing the location of surface plasmons over nanotriangle and nanohole arrays of different size and periodicity

The increasing popularity of surface plasmon resonance (SPR) and surface enhanced Raman scattering (SERS) sensor design based on nanotriangle or nanohole arrays, and the possibility to manufacture substrates at the transition between these plasmonic substrates, makes them ideal candidates for the establishment of structure-property relationships. This work features near diffraction-limited Raman images and finite-difference time-domain (FDTD) simulations of nanotriangle and nanohole array substrates, which clearly demonstrate that the localization of the hot spot on these SERS substrates is significantly influenced by the ratio of diameter/periodicity (D/P). The experimental and simulation data reveal that the hot spots are located around nanotriangles (D/P = 1), characteristic of localized SPR. Decreasing the D/P ratio to 0.75-0.7 led to the creation of nanohole arrays, which promoted the excitation of a propagating surface plasmon (SP) delocalized over the metal network. The optimal SERS intensity was consistently achieved at this transition from nanotriangles to nanoholes, for every periodicity (650 nm to 1.5 μm) and excitation wavelength (633 and 785 nm) investigated, despite the presence or absence of a plasmonic band near the laser excitation. Further decreasing the D/P ratio led to excitation of a localized SP located around the rim of nanohole arrays for D/P of 0.5-0.6, in agreement with previous reports. In addition, this manuscript provides the first evidence that the hot spots are positioned inside the hole for D/P of 0.4, with the center being the region of highest electric field and Raman intensity. The compelling experimental evidence and FDTD simulations offer an overall understanding of the plasmonic properties of nanohole arrays as SERS and SPR sensors, which is of significant value in advancing the diversity of applications from such surfaces. © 2012 American Chemical Society.

Authors
Correia-Ledo, D; Gibson, KF; Dhawan, A; Couture, M; Vo-Dinh, T; Graham, D; Masson, J-F
MLA Citation
Correia-Ledo, D, Gibson, KF, Dhawan, A, Couture, M, Vo-Dinh, T, Graham, D, and Masson, J-F. "Assessing the location of surface plasmons over nanotriangle and nanohole arrays of different size and periodicity." Journal of Physical Chemistry C 116.12 (2012): 6884-6892.
PMID
23977402
Source
scival
Published In
The Journal of Physical Chemistry C
Volume
116
Issue
12
Publish Date
2012
Start Page
6884
End Page
6892
DOI
10.1021/jp3009018

Guest editorial introduction to the issue on biophotonics - Part 2

Authors
Ilev, IK; Boppart, SA; Andersson-Engels, S; Kim, B-M; Vo-Dinh, T
MLA Citation
Ilev, IK, Boppart, SA, Andersson-Engels, S, Kim, B-M, and Vo-Dinh, T. "Guest editorial introduction to the issue on biophotonics - Part 2." IEEE Journal on Selected Topics in Quantum Electronics 18.4 (2012): 1267-1269.
Source
scival
Published In
IEEE Journal of Selected Topics in Quantum Electronics
Volume
18
Issue
4
Publish Date
2012
Start Page
1267
End Page
1269
DOI
10.1109/JSTQE.2012.2202206

Design and fabrication of fiber-optic nanoprobes for optical sensing

This paper describes the design and fabrication of fiber-optic nanoprobes developed for optical detection in single living cells. It is critical to fabricate probes with well-controlled nanoapertures for optimized spatial resolution and optical transmission. The detection sensitivity of fiber-optic nanoprobe depends mainly on the extremely small excitation volume that is determined by the aperture sizes and penetration depths. We investigate the angle dependence of the aperture in shadow evaporation of the metal coating onto the tip wall. It was found that nanoaperture diameters of approximately 50 nm can be achieved using a 25° tilt angle. On the other hand, the aperture size is sensitive to the subtle change of the metal evaporation angle and could be blocked by irregular metal grains. Through focused ion beam (FIB) milling, optical nanoprobes with well-defined aperture size as small as 200 nm can be obtained. Finally, we illustrate the use of the nanoprobes by detecting a fluorescent species, benzo[a] pyrene tetrol (BPT), in single living cells. A quantitative estimation of the numbers of BPT molecules detected using fiber-optic nanoprobes for BPT solutions shows that the limit of detection was approximately 100 molecules. © 2010 Zhang et al.

Authors
Zhang, Y; Dhawan, A; Vo-Dinh, T
MLA Citation
Zhang, Y, Dhawan, A, and Vo-Dinh, T. "Design and fabrication of fiber-optic nanoprobes for optical sensing." Nanoscale Research Letters 7 (2012): 6-18.
Source
scival
Published In
Nanoscale Research Letters
Volume
7
Publish Date
2012
Start Page
6
End Page
18
DOI
10.1186/1556-276X-7-18

Plasmonic coupling interference: A new approach for cancer diagnostics using SERS detection

We have developed a novel label-free approach referred to as plasmonic coupling interference (PCI) nanoprobes for nucleic acid detection using surface-enhanced Raman scattering (SERS). To induce a strong plasmonic coupling effect and SERS signal, a nano-network of silver nanoparticles having the Raman label located between adjacent nanoparticles is assembled by Raman-labeled nucleic acid duplexes. The PCI method then utilizes specific nucleic acid sequences of interest as competitor elements of the Raman-labeled DNA probes to interfere the formation of the nucleic acid-crosslinked nano-networks in a competitive binding process, resulting in a reduced SERS signal. We illustrate the potential of the PCI technique for biomedical applications by detecting single-nucleotide polymorphism (SNP) and microRNA sequences involved in breast cancers. The results of this study could lead to the development of nucleic acid diagnostic tools for biomedical diagnostics and biosensing applications using SERS detection. © 2012 SPIE.

Authors
Wang, H-N; Vo-Dinh, T
MLA Citation
Wang, H-N, and Vo-Dinh, T. "Plasmonic coupling interference: A new approach for cancer diagnostics using SERS detection." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 8214 (2012).
Source
scival
Published In
Proceedings of SPIE
Volume
8214
Publish Date
2012
DOI
10.1117/12.917630

Introduction to the issue on biophotonics-part 1

Authors
Ilev, IK; Boppart, SA; Engels, SA; Kim, B-M; Vo-Dinh, T
MLA Citation
Ilev, IK, Boppart, SA, Engels, SA, Kim, B-M, and Vo-Dinh, T. "Introduction to the issue on biophotonics-part 1." IEEE Journal on Selected Topics in Quantum Electronics 18.3 (2012): 1039-1041.
Source
scival
Published In
IEEE Journal of Selected Topics in Quantum Electronics
Volume
18
Issue
3
Publish Date
2012
Start Page
1039
End Page
1041
DOI
10.1109/JSTQE.2012.2187845

Optical nanosensors and nanoprobes: From single-cell exploration to medical diagnostics

This lecture presents an overview of recent advances in the development of optical nanobiosensor and nanoprobe technology at the nexus of engineering, biology, medicine and nanotechnology. The presentation describes two areas of research related to the development of nanoprobes and nanosensors for biomolecule detection and single-cell analysis : (1) plasmonics nanoprobes using surface-enhanced Raman scattering (SERS) detection; and (2) nanobiosensors for in vivo analysis of a single cell for molecular diagnostics and imaging, and ultra-high throughput screening. Novel nanobiosensors and nanoprobes combining bio-recognition and nanotechnology have been developed for in-vitro molecular diagnostics and in-vivo monitoring of biological targets and biochemical processes in a single living cell. These studies demonstrate applications of plasmonics molecular sentinel nanoprobes for diagnostics of diseases such as cancer and the use of nano-biosensors for measurements of molecular signaling pathways inside a single cell. Fiberoptics-based nanobiosensors are used to detect apoptotic processes in single cells following photodynamic cancer treatment or to monitor pH in cancer cells. These nanodevices open new possibilities to a wide range of applications in medical diagnostics at the point of care, global health, molecular imaging, biology research, ultra-high throughput screening, and investigations of the therapeutic action of pharmaceutical agents. © 2012 SPIE.

Authors
Vo-Dinh, T; Wang, H-N
MLA Citation
Vo-Dinh, T, and Wang, H-N. "Optical nanosensors and nanoprobes: From single-cell exploration to medical diagnostics." Proceedings of SPIE - The International Society for Optical Engineering 8421 (2012).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
8421
Publish Date
2012
DOI
10.1117/12.2007658

Plasmonic coupling interference (PCI) nanoprobes for nucleic acid detection.

A label-free approach using plasmonic coupling interference (PCI) nanoprobes for nucleic acid detection using surface-enhanced Raman scattering (SERS) is described. To induce a strong plasmonic coupling effect, a nanonetwork of silver nanoparticles with the Raman label located between adjacent nanoparticles is assembled by Raman-labeled DNA-locked nucleic acid (LNA) duplexes. The PCI method then utilizes specific nucleic acid sequences of interest as competitor elements for the Raman-labeled DNA strands to interfere the formation of nanonetworks in a competitive binding process. As a result, the plasmonic coupling effect induced through the formation of the nanonetworks is significantly diminished, resulting in a reduced SERS signal. The potential of the PCI technique for biomedical applications is illustrated by detecting single-nucleotide polymorphism (SNP) and microRNA sequences involved in breast cancers. The results of this study could lead to the development of nucleic acid diagnostic tools for biomedical diagnostics and biosensing applications using SERS detection.

Authors
Wang, H-N; Vo-Dinh, T
MLA Citation
Wang, H-N, and Vo-Dinh, T. "Plasmonic coupling interference (PCI) nanoprobes for nucleic acid detection." Small 7.21 (November 4, 2011): 3067-3074.
PMID
21913327
Source
pubmed
Published In
Small
Volume
7
Issue
21
Publish Date
2011
Start Page
3067
End Page
3074
DOI
10.1002/smll.201101380

Silica-coated gold nanostars for combined surface-enhanced Raman scattering (SERS) detection and singlet-oxygen generation: a potential nanoplatform for theranostics.

This paper reports the synthesis and characterization of surface-enhanced Raman scattering (SERS) label-tagged gold nanostars, coated with a silica shell containing methylene blue photosensitizing drug for singlet-oxygen generation. To our knowledge, this is the first report of nanocomposites possessing a combined capability for SERS detection and singlet-oxygen generation for photodynamic therapy. The gold nanostars were tuned for maximal absorption in the near-infrared (NIR) spectral region and tagged with a NIR dye for surface-enhanced resonance Raman scattering (SERRS). Silica coating was used to encapsulate the photosensitizer methylene blue in a shell around the nanoparticles. Upon 785 nm excitation, SERS from the Raman dye is observed, while excitation at 633 nm shows fluorescence from methylene blue. Methylene-blue-encapsulated nanoparticles show a significant increase in singlet-oxygen generation as compared to nanoparticles synthesized without methylene blue. This increased singlet-oxygen generation shows a cytotoxic effect on BT549 breast cancer cells upon laser irradiation. The combination of SERS detection (diagnostic) and singlet-oxygen generation (therapeutic) into a single platform provides a potential theranostic agent.

Authors
Fales, AM; Yuan, H; Vo-Dinh, T
MLA Citation
Fales, AM, Yuan, H, and Vo-Dinh, T. "Silica-coated gold nanostars for combined surface-enhanced Raman scattering (SERS) detection and singlet-oxygen generation: a potential nanoplatform for theranostics." Langmuir 27.19 (October 4, 2011): 12186-12190.
PMID
21859159
Source
pubmed
Published In
Langmuir
Volume
27
Issue
19
Publish Date
2011
Start Page
12186
End Page
12190
DOI
10.1021/la202602q

Activity of psoralen-functionalized nanoscintillators against cancer cells upon X-ray excitation.

We report development of a nanoparticle-based, X-ray-activated anticancer "nanodrug" composed of yttrium oxide (Y(2)O(3)) nanoscintillators, a fragment of the HIV-1 TAT peptide, and psoralen. In this formulation, X-ray radiation is absorbed by the Y(2)O(3) nanoscintillators, which then emit UVA light. Absorption of UVA photons by nanoparticle-tethered psoralen has the potential to cross-link adenine and thymine residues in DNA. UVA-induced cross-linking by free psoralen upon activation with UVA light has previously been shown to cause apoptosis in vitro and an immunogenic response in vivo. Studies using the PC-3 human prostate cancer cell line demonstrate that X-ray excitation of these psoralen-functionalized Y(2)O(3) nanoscintillators yields concentration-dependent reductions in cell number when compared to control cultures containing psoralen-free Y(2)O(3) nanoscintillators.

Authors
Scaffidi, JP; Gregas, MK; Lauly, B; Zhang, Y; Vo-Dinh, T
MLA Citation
Scaffidi, JP, Gregas, MK, Lauly, B, Zhang, Y, and Vo-Dinh, T. "Activity of psoralen-functionalized nanoscintillators against cancer cells upon X-ray excitation." ACS Nano 5.6 (June 28, 2011): 4679-4687.
PMID
21553850
Source
pubmed
Published In
ACS Nano
Volume
5
Issue
6
Publish Date
2011
Start Page
4679
End Page
4687
DOI
10.1021/nn200511m

Deep UV nano-microstructuring of substrates for surface plasmon resonance imaging.

In this paper, we describe wafer-scale fabrication and characterization of plasmonic chips-containing different sizes and spacings of metallic micro- and nanoline structures-using deep UV lithography. Using a high dose (25 mJ cm( - 2)) and a proper lift-off process, feature sizes as small as 25 nm are obtained. Moreover, we study the dependence of surface plasmon resonance on the angle of incidence and wavelength for different micro- and nanoline size and spacing values, yielding localized to quasi-propagative plasmonic behaviors. Rigorous coupled wave analysis (RCWA) techniques are employed to numerically confirm these experimental observations. Finally, the refractive index of media around the SPRI sensor chips is varied, showing the angulo-spectral regions of higher sensitivity for each type of structure.

Authors
Dhawan, A; Duval, A; Nakkach, M; Barbillon, G; Moreau, J; Canva, M; Vo-Dinh, T
MLA Citation
Dhawan, A, Duval, A, Nakkach, M, Barbillon, G, Moreau, J, Canva, M, and Vo-Dinh, T. "Deep UV nano-microstructuring of substrates for surface plasmon resonance imaging." Nanotechnology 22.16 (April 22, 2011): 165301-.
PMID
21393822
Source
pubmed
Published In
Nanotechnology
Volume
22
Issue
16
Publish Date
2011
Start Page
165301
DOI
10.1088/0957-4484/22/16/165301

Hybrid top-down and bottom-up fabrication approach for wafer-scale plasmonic nanoplatforms.

Authors
Dhawan, A; Du, Y; Batchelor, D; Wang, H-N; Leonard, D; Misra, V; Ozturk, M; Gerhold, MD; Vo-Dinh, T
MLA Citation
Dhawan, A, Du, Y, Batchelor, D, Wang, H-N, Leonard, D, Misra, V, Ozturk, M, Gerhold, MD, and Vo-Dinh, T. "Hybrid top-down and bottom-up fabrication approach for wafer-scale plasmonic nanoplatforms." Small 7.6 (March 21, 2011): 727-731.
PMID
21425456
Source
pubmed
Published In
Small
Volume
7
Issue
6
Publish Date
2011
Start Page
727
End Page
731
DOI
10.1002/smll.201002186

Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics.

We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivity to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection.

Authors
Liu, Q; Grant, G; Li, J; Zhang, Y; Hu, F; Li, S; Wilson, C; Chen, K; Bigner, D; Vo-Dinh, T
MLA Citation
Liu, Q, Grant, G, Li, J, Zhang, Y, Hu, F, Li, S, Wilson, C, Chen, K, Bigner, D, and Vo-Dinh, T. "Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics." J Biomed Opt 16.3 (March 2011): 037004-.
PMID
21456877
Source
pubmed
Published In
Journal of Biomedical Optics
Volume
16
Issue
3
Publish Date
2011
Start Page
037004
DOI
10.1117/1.3558840

Characterization of nanoprobe uptake in single cells: spatial and temporal tracking via SERS labeling and modulation of surface charge.

UNLABELLED: A critical aspect for use of nanoprobes in biomedical research and clinical applications involves fundamental spatial and temporal characterization of their uptake and distribution in cells. Raman spectroscopy and two-dimensional Raman imaging were used to identify and locate nanoprobes in single cells using surface-enhanced Raman scattering detection. To study the efficiency of cellular uptake, silver nanoparticles functionalized with three different positive-, negative-, and neutrally charged Raman labels were co-incubated with cell cultures and internalized via normal cellular processes. The surface charge on the nanoparticles was observed to modulate uptake efficiency, demonstrating a dual function of the surface modifications as tracking labels and as modulators of cell uptake. These results indicate that the functionalized nanoparticle construct has potential for sensing and delivery in single living cells and that use of surface-enhanced Raman scattering for tracking and detection is a practical and advantageous alternative to traditional fluorescence methods. FROM THE CLINICAL EDITOR: Cell labeling and tracking methods are commonly required in biomedical research. This paper presents specific functionalized nanoparticle constructs with potential for sensing and delivery in single living cells. The use of surface-enhanced Raman scattering enables tracking and detection of these cells as a practical alternative to traditional fluorescence methods.

Authors
Gregas, MK; Yan, F; Scaffidi, J; Wang, H-N; Vo-Dinh, T
MLA Citation
Gregas, MK, Yan, F, Scaffidi, J, Wang, H-N, and Vo-Dinh, T. "Characterization of nanoprobe uptake in single cells: spatial and temporal tracking via SERS labeling and modulation of surface charge." Nanomedicine 7.1 (February 2011): 115-122.
PMID
20817123
Source
pubmed
Published In
Nanomedicine: Nanotechnology, Biology and Medicine
Volume
7
Issue
1
Publish Date
2011
Start Page
115
End Page
122
DOI
10.1016/j.nano.2010.07.009

Narrow groove plasmonic nano-gratings for surface plasmon resonance sensing.

We present a novel surface plasmon resonance (SPR) configuration based on narrow groove (sub-15 nm) plasmonic nano-gratings such that normally incident radiation can be coupled into surface plasmons without the use of prism-coupling based total internal reflection, as in the classical Kretschmann configuration. This eliminates the angular dependence requirements of SPR-based sensing and allows development of robust miniaturized SPR sensors. Simulations based on Rigorous Coupled Wave Analysis (RCWA) were carried out to numerically calculate the reflectance - from different gold and silver nano-grating structures - as a function of the localized refractive index of the media around the SPR nano-gratings as well as the incident radiation wavelength and angle of incidence. Our calculations indicate substantially higher differential reflectance signals, on localized change of refractive index in the narrow groove plasmonic gratings, as compared to those obtained from conventional SPR-based sensing systems. Furthermore, these calculations allow determination of the optimal nano-grating geometric parameters - i. e. nanoline periodicity, spacing between the nanolines, as well as the height of the nanolines in the nano-grating - for highest sensitivity to localized change of refractive index, as would occur due to binding of a biomolecule target to a functionalized nano-grating surface.

Authors
Dhawan, A; Canva, M; Vo-Dinh, T
MLA Citation
Dhawan, A, Canva, M, and Vo-Dinh, T. "Narrow groove plasmonic nano-gratings for surface plasmon resonance sensing." Opt Express 19.2 (January 17, 2011): 787-813.
PMID
21263620
Source
pubmed
Published In
Optics express
Volume
19
Issue
2
Publish Date
2011
Start Page
787
End Page
813

Single-cell monitoring using fiberoptic nanosensors.

This article is a review on the design, fabrication, and applications of fiberoptic nanosensors for in vivo monitoring of individual living cells. The nanosensors were fabricated with tapered optical fibers with distal ends having nanometer-sized diameters. Bioreceptors, such as antibody, peptides, and nucleic acids, are immobilized on the fiber tips and designed to be selective to target analyte molecules of interest. A laser beam is transmitted into the fiber, producing an evanescent field at the tip of the nanofiber that is used to excite target molecules bound to the bioreceptor molecules. The fluorescence originated from the analyte molecules is detected by a photo-detection system. The advantages and limitations of nanosensors in providing minimally invasive tools to probe subcellular compartments inside individual living cells for health effect studies and medical applications are discussed in detail.

Authors
Vo-Dinh, T; Zhang, Y
MLA Citation
Vo-Dinh, T, and Zhang, Y. "Single-cell monitoring using fiberoptic nanosensors." Wiley Interdiscip Rev Nanomed Nanobiotechnol 3.1 (January 2011): 79-85. (Review)
PMID
20677238
Source
pubmed
Published In
Wiley interdisciplinary reviews. Nanomedicine and nanobiotechnology
Volume
3
Issue
1
Publish Date
2011
Start Page
79
End Page
85
DOI
10.1002/wnan.112

Nanotechnology research and development for military and industrial applications

Researchers at the Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC) have initiated multidiscipline efforts to develop nano-based structures and components for insertion into advanced missile, aviation, and autonomous air and ground systems. The objective of the research is to exploit unique phenomena for the development of novel technology to enhance warfighter capabilities and produce precision weapons. The key technology areas that the authors are exploring include nano-based microsensors, nano-energetics, nano-batteries, nano-composites, and nano-plasmonics. By integrating nano-based devices, structures, and materials into weaponry, the Army can revolutionize existing (and future) missile systems by significantly reducing the size, weight and cost. The major research thrust areas include the development of chemical sensors to detect rocket motor off-gassing and toxic industrial chemicals; the development of highly sensitive/selective, self-powered miniaturized acoustic sensors for battlefield surveillance and reconnaissance; the development of a minimum signature solid propellant with increased ballistic and physical properties that meet insensitive munitions requirements; the development of nano-structured material for higher voltage thermal batteries and higher energy density storage; the development of advanced composite materials that provide high frequency damping for inertial measurement units' packaging; and the development of metallic nanostructures for ultraviolet surface enhanced Raman spectroscopy. The current status of the overall AMRDEC Nanotechnology research efforts is disclosed in this paper. Critical technical challenges, for the various technologies, are presented. The authors' approach for overcoming technical barriers and achieving required performance is also discussed. Finally, the roadmap for each technology, as well as the overall program, is presented. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Authors
Ruffin, PB; Brantley, CL; Edwards, E; Roberts, JK; Chew, W; Warren, LC; Ashley, PR; Everitt, HO; Webster, E; Foreman, JV; Sanghadasa, M; Crutcher, SH; Temmen, MG; Varadan, V; Hayduke, D; Wu, PC; Khoury, CG; Yang, Y; Kim, T-H; Vo-Dinh, T; Brown, AS; Callahan, J
MLA Citation
Ruffin, PB, Brantley, CL, Edwards, E, Roberts, JK, Chew, W, Warren, LC, Ashley, PR, Everitt, HO, Webster, E, Foreman, JV, Sanghadasa, M, Crutcher, SH, Temmen, MG, Varadan, V, Hayduke, D, Wu, PC, Khoury, CG, Yang, Y, Kim, T-H, Vo-Dinh, T, Brown, AS, and Callahan, J. "Nanotechnology research and development for military and industrial applications." Proceedings of SPIE - The International Society for Optical Engineering 7980 (2011).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
7980
Publish Date
2011
DOI
10.1117/12.878970

Micro- and nanotopographies for photoelectrochemical energy conversion. II: Photoelectrocatalysis - Classical and advanced systems

The present trends on water photolysis are shortly reviewed. For application in monolithically integrated structures, photoelectrocatalytically active half cell developments with p-Si are described. Using the concept of nanoemitter minority carrier harvesting, it is shown that the introduction of traces of noble metal catalysts that allow collection of light-induced carriers does not result in cost or scarcity limitations. The issue of charge transfer through an interfacial oxide and ballistic electron injection into the electrolyte vs. thermalization is discussed. The experimental data shows that the nanoemitter system can sustain the high current densities resulting from injected light-induced excess carriers from the semiconductor at low overvoltages. Limitations of planar systems with Si are discussed and possible improvements are outlined. First tests of Si rod-like microstructures are presented and the influence of localized surface plasmon excitation on light-induced H2 evolution with p-Si is investigated. © 2011 Elsevier Ltd. All rights reserved.

Authors
Lewerenz, HJ; Skorupska, K; Muñoz, AG; Stempel, T; Nüsse, N; Lublow, M; Vo-Dinh, T; Kulesza, P
MLA Citation
Lewerenz, HJ, Skorupska, K, Muñoz, AG, Stempel, T, Nüsse, N, Lublow, M, Vo-Dinh, T, and Kulesza, P. "Micro- and nanotopographies for photoelectrochemical energy conversion. II: Photoelectrocatalysis - Classical and advanced systems." Electrochimica Acta 56.28 (2011): 10726-10736.
Source
scival
Published In
Electrochimica Acta
Volume
56
Issue
28
Publish Date
2011
Start Page
10726
End Page
10736
DOI
10.1016/j.electacta.2011.05.028

Plasmonics quenching and enhancement of a fluorescing molecule outside and inside a silver metallic nanoshell

Analytic expressions are derived for the enhancement and quenching of a fluorescing molecule outside and in the interior of a metallic spherical nanoshell. The competing effects of enhancement and quenching are a strong function of the radial location of a molecule exterior to the shell. For a fluorescing molecule inside the shell, the enhancement and quenching are a weaker function of radius and a stronger function of the shell thickness. The enhancement and quenching also have a strong wavelength dependence arising from plasmon resonances excited within the particle. For an external molecule, a shell produces a larger peak enhancement than a solid homogeneous sphere of the same diameter. Calculations are presented to illustrate these effects in a silver shell. © 2011 IEEE.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Plasmonics quenching and enhancement of a fluorescing molecule outside and inside a silver metallic nanoshell." IEEE Transactions on Nanotechnology 10.6 (2011): 1264-1274.
Source
scival
Published In
IEEE Transactions on Nanotechnology
Volume
10
Issue
6
Publish Date
2011
Start Page
1264
End Page
1274
DOI
10.1109/TNANO.2011.2124471

Amplification of fluorescence emission of CdSe/ZnS QDs entrapped in a sol-gel matrix, a new approach for detection of trace level of PAHs

In this work, CdSe/ZnS core/shell QDs with emission wavelengths of 535 nm, 545 nm, 555 nm and 575 nm were synthesized and the ligands on their surface were exchanged with mercaptopropionic acid (MPA) to make them water-soluble. Hydrophilic QDs were incorporated into a sol-gel GA matrix of 3-aminopropyl trimethoxysilane (APTMS) and 3-glycidoxypropyl trimethoxysilane (GPTMS) to fabricate QD-entrapped membranes. The fluorescence intensity of the QDs entrapped in the sol-gel membrane was increased after being activated by the energy transfer from polycyclic aromatic hydrocarbon compounds (PAHs). The signal increase of the QDs was proportional to the increase in the concentration of the PAHs. Herein, trace levels of anthracene (ANT), phenanthrene (PHE) and pyrene (PYR) were detected through the enhancement of the fluorescence intensity of the CdSe/ZnS QD-entrapped membranes. The linear detection ranges were 0.01-0.1 μM for ANT and PHE and 0.005-0.05 μM for PYR. The QD-entrapped sol-gel membranes also showed quite good stability for the detection of PAHs over a period of 2 months. © 2011 Elsevier B.V. All rights reserved.

Authors
Duong, HD; Reddy, CVG; Rhee, JI; Vo-Dinh, T
MLA Citation
Duong, HD, Reddy, CVG, Rhee, JI, and Vo-Dinh, T. "Amplification of fluorescence emission of CdSe/ZnS QDs entrapped in a sol-gel matrix, a new approach for detection of trace level of PAHs." Sensors and Actuators, B: Chemical 157.1 (2011): 139-145.
Source
scival
Published In
Sensors and Actuators B: Chemical
Volume
157
Issue
1
Publish Date
2011
Start Page
139
End Page
145
DOI
10.1016/j.snb.2011.03.038

Design and fabrication of fiber-optic nanoprobes for optical sensing

This paper describes the design and fabrication of fiber-optic nanoprobes developed for optical detection in single living cells. It is critical to fabricate probes with well-controlled nanoapertures for optimized spatial resolution and optical transmission. The detection sensitivity of fiber-optic nanoprobe depends mainly on the extremely small excitation volume that is determined by the aperture sizes and penetration depths. We investigate the angle dependence of the aperture in shadow evaporation of the metal coating onto the tip wall. It was found that nanoaperture diameters of approximately 50 nm can be achieved using a 25° tilt angle. On the other hand, the aperture size is sensitive to the subtle change of the metal evaporation angle and could be blocked by irregular metal grains. Through focused ion beam (FIB) milling, optical nanoprobes with well-defined aperture size as small as 200 nm can be obtained. Finally, we illustrate the use of the nanoprobes by detecting a fluorescent species, benzo[a] pyrene tetrol (BPT), in single living cells. A quantitative estimation of the numbers of BPT molecules detected using fiber-optic nanoprobes for BPT solutions shows that the limit of detection was approximately 100 molecules. © 2010 Zhang et al.

Authors
Zhang, Y; Dhawan, A; Vo-Dinh, T
MLA Citation
Zhang, Y, Dhawan, A, and Vo-Dinh, T. "Design and fabrication of fiber-optic nanoprobes for optical sensing." Nanoscale Research Letters 6 (2011): 6-18.
PMID
27502642
Source
scival
Published In
Nanoscale Research Letters
Volume
6
Publish Date
2011
Start Page
6
End Page
18

Design and Fabrication of Fiber-Optic Nanoprobes for Optical Sensing

This paper describes the design and fabrication of fiber-optic nanoprobes developed for optical detection in single living cells. It is critical to fabricate probes with well-controlled nanoapertures for optimized spatial resolution and optical transmission. The detection sensitivity of fiber-optic nanoprobe depends mainly on the extremely small excitation volume that is determined by the aperture sizes and penetration depths. We investigate the angle dependence of the aperture in shadow evaporation of the metal coating onto the tip wall. It was found that nanoaperture diameters of approximately 50 nm can be achieved using a 25° tilt angle. On the other hand, the aperture size is sensitive to the subtle change of the metal evaporation angle and could be blocked by irregular metal grains. Through focused ion beam (FIB) milling, optical nanoprobes with well-defined aperture size as small as 200 nm can be obtained. Finally, we illustrate the use of the nanoprobes by detecting a fluorescent species, benzo[a]pyrene tetrol (BPT), in single living cells. A quantitative estimation of the numbers of BPT molecules detected using fiber-optic nanoprobes for BPT solutions shows that the limit of detection was approximately 100 molecules. © 2010 The Author(s).

Authors
Zhang, Y; Dhawan, A; Vo-Dinh, T
MLA Citation
Zhang, Y, Dhawan, A, and Vo-Dinh, T. "Design and Fabrication of Fiber-Optic Nanoprobes for Optical Sensing." Nanoscale Research Letters 6.1 (2011): 1-6.
Source
scival
Published In
Nanoscale Research Letters
Volume
6
Issue
1
Publish Date
2011
Start Page
1
End Page
6
DOI
10.1007/s11671-010-9744-5

Nanostructured substrates for surface plasmon resonance sensors

Surface Plasmon Resonance (SPR) sensors are usually based on continuous thin metallic films and coupling of propagative plasmon (PP) modes using high index prism or grating. The quantitative monitoring of the surface evolution is performed by measuring either shift in angular or spectral dip position, or by reflectivity variation in the slope of the angulo-spectral coupling curve. Such sensors are studied in many laboratories and used in a growing number of commercial devices. It appears however that these systems are reaching their limits in terms of sensitivity [1]. In the field of plasmonic sensing, many other works are devoted to the study of metallic nanoparticles. We anticipate that using nanostructured substrates for exciting coupled localized plasmon (CLP) or quasi propagating plasmon (QPP) will allow to further increase the sensors capabilities, in particular in terms of sensitivity. Samples were realized using either e-beam or deep-UV lithography based techniques. Experimental characterizations were conducted using lab-made angulo-spectral SPR Imaging systems [2]. Using RCWA simulations, we have calculated the plasmonics responses, in term of angulo-spectral reflectivity, of nanostructures. A novel narrow groove plasmonic nano-grating sensing configuration exhibits the highest potential [3]. © 2011 IEEE.

Authors
Duval, A; Nakkach, M; Bellemain, A; Moreau, J; Canva, M; Dhawan, A; Vo-Dinh, T
MLA Citation
Duval, A, Nakkach, M, Bellemain, A, Moreau, J, Canva, M, Dhawan, A, and Vo-Dinh, T. "Nanostructured substrates for surface plasmon resonance sensors." 2011 International Workshop on Biophotonics, BIOPHOTONICS 2011 (2011).
Source
scival
Published In
2011 International Workshop on Biophotonics, BIOPHOTONICS 2011
Publish Date
2011
DOI
10.1109/IWBP.2011.5954821

Plasmonics nanoprobes: detection of single-nucleotide polymorphisms in the breast cancer BRCA1 gene.

This paper describes the application of plasmonics-based nanoprobes that combine the modulation of the plasmonics effect to change the surface-enhanced Raman scattering (SERS) of a Raman label and the specificity of a DNA hairpin loop sequence to recognize and discriminate a variety of molecular target sequences. Hybridization with target DNA opens the hairpin and physically separates the Raman label from the metal nanoparticle thus reducing the plasmonics effect and quenching the SERS signal of the label. We have successfully demonstrated the specificity and selectivity of the nanoprobes in the detection of a single-nucleotide polymorphism (SNP) in the breast cancer BRCA1 gene in a homogenous solution at room temperature. In addition, the potential application of plasmonics nanoprobes for quantitative DNA diagnostic testing is discussed.

Authors
Wabuyele, MB; Yan, F; Vo-Dinh, T
MLA Citation
Wabuyele, MB, Yan, F, and Vo-Dinh, T. "Plasmonics nanoprobes: detection of single-nucleotide polymorphisms in the breast cancer BRCA1 gene." Anal Bioanal Chem 398.2 (September 2010): 729-736.
PMID
20676618
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
398
Issue
2
Publish Date
2010
Start Page
729
End Page
736
DOI
10.1007/s00216-010-3992-1

A novel cyanide ion sensing approach based on Raman scattering for the detection of environmental cyanides.

This paper describes a direct optical approach based on Raman scattering for selective and sensitive detection of cyanide ions in aqueous environment without requiring time-consuming sample pretreatment and the formation of hydrogen cyanide. Due to the strong affinity between copper (I) and cyanide ion, evaporated copper (I) iodide (CuI) thin films are shown to be excellent substrates for selective recognition of free cyanide ions in aqueous matrices. The amount of cyanide ion retained by the copper (I) in the CuI thin films reflects its actual concentration in tested samples, and the subsequent Raman measurements of the substrate are shown to be capable of detecting toxic cyanide content at levels under international drinking water standard and environmental regulatory concentrations. Measurements obtained from the same batch of evaporated CuI thin films (approximately 100-nm thickness) show excellent linearity over a variety of cyanide concentrations ranging from 1.5 microM to 0.15 mM. This detection method offers the advantage of selectively detecting cyanides causing a health hazard while avoiding detection of other common interfering anions such as Cl-, Br-, PO4(3-), SO4(2-), NO2-, S2- and SCN-. Coupled with portable Raman systems that are commercially available, our detection approach will provide on-site monitoring capability with little sample preparation or instrument supervision, which will greatly expedite the assessment of potential environmental cyanide risks.

Authors
Yan, F; Gopal Reddy, CV; Zhang, Y; Vo-Dinh, T
MLA Citation
Yan, F, Gopal Reddy, CV, Zhang, Y, and Vo-Dinh, T. "A novel cyanide ion sensing approach based on Raman scattering for the detection of environmental cyanides." Ecotoxicol Environ Saf 73.6 (September 2010): 1490-1494.
PMID
20541261
Source
pubmed
Published In
Ecotoxicology and Environmental Safety
Volume
73
Issue
6
Publish Date
2010
Start Page
1490
End Page
1494
DOI
10.1016/j.ecoenv.2010.02.018

Investigating the plasmonics of a dipole-excited silver nanoshell: Mie theory versus finite element method.

This report compares COMSOL's finite element method (FEM) algorithm with the Mie theory for solving the electromagnetic fields in the vicinity of a silica-silver core-shell nanoparticle when excited by a radiating dipole. The novelty of this investigation lies in the excitation source of the nanoshell system: an oscillating electric dipole is frequently used as a model for both molecular scattering and molecular fluorescence; moreover, a common classical model of atomic or molecular spontaneous emission is a decaying electric dipole. The radiated power spectra were evaluated both analytically and numerically by integrating the Poynting vector around 20, 60 and 100 nm nanoshells, thereby solving the total and scattered fields generated by a dipole positioned inside the core and in the surrounding air medium, respectively. The agreement was excellent in amplitude, plasmon resonance peak position and full width at half-maximum. The FEM algorithm also generates accurate solutions of the near-field electromagnetics in the spatial domain, where the E-field behavior as a function of polar angle theta for a fixed observation radius was evaluated. The quasistatic approximation, which is valid for small nanoparticles, is also employed to assess its limitations relative to the Mie and FEM algorithms.

Authors
Khoury, CG; Norton, SJ; Vo-Dinh, T
MLA Citation
Khoury, CG, Norton, SJ, and Vo-Dinh, T. "Investigating the plasmonics of a dipole-excited silver nanoshell: Mie theory versus finite element method." Nanotechnology 21.31 (August 6, 2010): 315203-.
PMID
20634565
Source
pubmed
Published In
Nanotechnology
Volume
21
Issue
31
Publish Date
2010
Start Page
315203
DOI
10.1088/0957-4484/21/31/315203

Surface-enhanced Raman scattering detection and tracking of nanoprobes: enhanced uptake and nuclear targeting in single cells.

We describe the development and application of a co-functionalized nanoprobe and biodelivery platform combining a nuclear targeting peptide (NTP) for improved cellular uptake and intracellular targeting with p-mercaptobenzoic acid (pMBA) as a surface-enhanced Raman scattering (SERS) reporter for tracking and imaging. The nuclear targeting peptide, an HIV-1 protein-derived TAT sequence, has been previously shown to aid entry of cargo through the cell membrane via normal cellular processes, and furthermore, to localize small cargo to the nucleus of the cell. Previous work in our lab has verified cell uptake and distribution of the nanoprobes in clinically relevant mouse and human cell lines. In this work, two-dimensional SERS mapping was used to track the spatial and temporal progress of nanoparticle uptake in PC-3 human prostate cells and to characterize localization at various time points, demonstrating the potential for an intracellularly targeted multiplexed nanobiosensing system with excellent sensitivity and specificity. Silver nanoparticles co-functionalized with the TAT peptide showed greatly enhanced cellular uptake over the control nanoparticles lacking the targeting moiety. The ability to detect and monitor nanoprobe trafficking using SERS spectroscopy offers an improved alternative over previous tracking and detection methods such as light microscopy and fluorescence methods. The development of multifunctional nanoconstructs for intracellular delivery has potential clinical applications in early detection and selective treatment of disease in affected cells. Other applications include use in basic research aimed at understanding the inner workings of living cells and how they respond to chemical and biological stimuli.

Authors
Gregas, MK; Scaffidi, JP; Lauly, B; Vo-Dinh, T
MLA Citation
Gregas, MK, Scaffidi, JP, Lauly, B, and Vo-Dinh, T. "Surface-enhanced Raman scattering detection and tracking of nanoprobes: enhanced uptake and nuclear targeting in single cells." Appl Spectrosc 64.8 (August 2010): 858-866.
PMID
20719048
Source
pubmed
Published In
Applied spectroscopy
Volume
64
Issue
8
Publish Date
2010
Start Page
858
End Page
866
DOI
10.1366/000370210792081037

Trace molecular detection via surface-enhanced Raman scattering and surface-enhanced resonance Raman scattering at a distance of 15 meters.

We report the first demonstration of surface-enhanced Raman spectroscopy (SERS) detection of para-mercapto benzoic acid (pMBA) and surface-enhanced resonance Raman spectroscopy (SERRS) detection of brilliant cresyl blue (BCB) and cresyl violet perchlorate (CVP) with continuous-wave excitation from a stand-off distance of 15 meters. We further report the first stand-off SERRS detection of BCB and CVP at that same distance in the presence of ambient fluorescent and incandescent/blackbody background light. These preliminary results suggest that it is possible to detect sub-nanomole amounts of material at reasonable distances with eye-safe laser powers using stand-off SERRS and serve as proof-of-concept highlighting the potential extension of stand-off Raman spectroscopy to include SERS and SERRS for remote, eye-safe chemical detection, analysis, and imaging in the presence of ambient background light.

Authors
Scaffidi, JP; Gregas, MK; Lauly, B; Carter, JC; Angel, SM; Vo-Dinh, T
MLA Citation
Scaffidi, JP, Gregas, MK, Lauly, B, Carter, JC, Angel, SM, and Vo-Dinh, T. "Trace molecular detection via surface-enhanced Raman scattering and surface-enhanced resonance Raman scattering at a distance of 15 meters." Appl Spectrosc 64.5 (May 2010): 485-492.
PMID
20482966
Source
pubmed
Published In
Applied spectroscopy
Volume
64
Issue
5
Publish Date
2010
Start Page
485
End Page
492
DOI
10.1366/000370210791211763

Cellular uptake and photodynamic activity of protein nanocages containing methylene blue photosensitizing drug.

This study reports that photosensitizers encapsulated in supramolecular protein cages can be internalized by tumor cells and can deliver singlet oxygen intracellularly for photodynamic therapy (PDT). As an alternative to other polymeric and/or inorganic nanocarriers and nanoconjugates, which may also deliver photosensitizers to the inside of the target cells, protein nanocages provide a unique vehicle of biological origin for the intracellular delivery of photosensitizing molecules for PDT by protecting the photosensitizers from reactive biomolecules in the cell membranes, and yet providing a coherent, critical mass of destructive power (by way of singlet oxygen) upon specific light irradiation for photodynamic therapy of tumor cells. As a model, we demonstrated the successful encapsulation of methylene blue (MB) in apoferritin via a dissociation-reassembly process controlled by pH. The resulting MB-containing apoferritin nanocages show a positive effect on singlet oxygen production, and cytotoxic effects on MCF-7 human breast adenocarcinoma cells when irradiated at the appropriate wavelength (i.e. 633 nm).

Authors
Yan, F; Zhang, Y; Kim, KS; Yuan, H-K; Vo-Dinh, T
MLA Citation
Yan, F, Zhang, Y, Kim, KS, Yuan, H-K, and Vo-Dinh, T. "Cellular uptake and photodynamic activity of protein nanocages containing methylene blue photosensitizing drug." Photochem Photobiol 86.3 (May 2010): 662-666.
PMID
20132513
Source
pubmed
Published In
Photochemistry & Photobiology
Volume
86
Issue
3
Publish Date
2010
Start Page
662
End Page
666
DOI
10.1111/j.1751-1097.2009.00696.x

Plasmonic nanoprobes for SERS biosensing and bioimaging.

This article provides an overview of the development and application of plasmonic nanoprobes developed in our laboratory for biosensing and bioimaging. We describe the use of plasmonics surface-enhanced Raman scattering (SERS) gene probes for the detection of diseases using DNA hybridization to target biospecies (HIV gene, breast cancer genes etc.). For molecular imaging, we describe a hyperspectral surface-enhanced Raman imaging (HSERI) system that combines imaging capabilities with SERS detection to identify cellular components using Raman dye-labeled silver nanoparticles in cellular systems The detection of specific target DNA sequences associated with breast cancer using "molecular sentinel" nanoprobes and the use of a plasmonic nanosensor to monitor pH in single cells are presented and discussed.

Authors
Vo-Dinh, T; Wang, H-N; Scaffidi, J
MLA Citation
Vo-Dinh, T, Wang, H-N, and Scaffidi, J. "Plasmonic nanoprobes for SERS biosensing and bioimaging." J Biophotonics 3.1-2 (January 2010): 89-102. (Review)
PMID
19517422
Source
pubmed
Published In
Journal of biophotonics
Volume
3
Issue
1-2
Publish Date
2010
Start Page
89
End Page
102
DOI
10.1002/jbio.200910015

Investigation of synchronous fluorescence method in multicomponent analysis in tissue

We investigate the advantages and disadvantages of the synchronous fluorescence (SF) scan method as compared with the fixed-excitation or fixed-emission fluorescence methods in analyzing biological tissue samples or tissue-like synthetic phantoms by quantitatively comparing the accuracy of multicomponent analysis in nonscattering phantoms and qualitatively comparing the spectral profiles of fluorescence spectra measured from tissue-like phantoms and ex vivo rat brains. The results of experiments in nonscattering phantoms indicate that the synchronous scan method with an appropriate wavelength interval (Δλ, i.e., the difference between the excitation wavelength and emission wavelength) always yields the highest overall quantification accuracy in a single scan. The results of experiments in tissue-like phantoms and exvivo rat brains suggest that the synchronous scan effectively examines the fluorescence peaks of multiple fluorophores in one single scan, reduce the overlap between fluorescence peaks of different endogenous fluorophores, and express/suppress the effect of specific absorption peaks on the shapes of fluorescence spectra. These features greatly facilitate the qualitative interpretation of fluorescence spectra from tissue samples or tissue-like phantoms. Finally, it is worth pointing out that background signals could exert a greater impact on the spectral shape for small wavelength intervals (Δ λ < 40 nm) compared to excitation or emission scans. © 2010 IEEE.

Authors
Liu, Q; Grant, G; Vo-Dinh, T
MLA Citation
Liu, Q, Grant, G, and Vo-Dinh, T. "Investigation of synchronous fluorescence method in multicomponent analysis in tissue." IEEE Journal on Selected Topics in Quantum Electronics 16.4 (2010): 927-940.
Source
scival
Published In
IEEE Journal of Selected Topics in Quantum Electronics
Volume
16
Issue
4
Publish Date
2010
Start Page
927
End Page
940
DOI
10.1109/JSTQE.2009.2031162

Resonant infrared matrix-assisted pulsed laser evaporation of inorganic nanoparticles and organic/inorganic hybrid nanocomposites

In this research, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been used to deposit different classes of inorganic nanoparticles, including bare, un-encapsulated ZnO and Au nanoparticles, as well as ligand-encapsulated CdSe colloidal quantum dots (CQDs). RIR-MAPLE has been used for thin-film deposition of different organic/inorganic hybrid nanocomposites using some of these inorganic nanoparticles, including CdSe CQD-poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-(1-cyanovinylene)phenylene] (MEH-CN-PPV) nanocomposites and Au nanoparticle-poly(methyl methacrylate) (PMMA) nanocomposites. The unique contribution of this research is that a technique is demonstrated for the deposition of organic-based thin-films requiring solvents with bond energies that do not have to be resonant with the laser energy. By creating an emulsion of solvent and ice in the target, RIR-MAPLE using a 2.94 μm laser can deposit most material systems because the hydroxyl bonds in the ice component of the emulsion matrix are strongly resonant with the 2.94 μm laser. In this way, the types of materials that can be deposited using RIR-MAPLE has been significantly expanded. Furthermore, materials with different solvent bond energies can be co-deposited without concern for material degradation and without the need to specifically tune the laser energy to each material solvent bond energy, thereby facilitating the realization of organic/inorganic hybrid nanocomposite thin-films. In addition to the structural characterization of the inorganic nanoparticle and hybrid nanocomposite thin-films deposited using this RIR-MAPLE technique, optical characterization is presented to demonstrate the potential of such films for optoelectronic device applications. © 2010 American Institute of Physics.

Authors
Pate, R; Lantz, KR; Dhawan, A; Vo-Dinh, T; Stiff-Roberts, AD
MLA Citation
Pate, R, Lantz, KR, Dhawan, A, Vo-Dinh, T, and Stiff-Roberts, AD. "Resonant infrared matrix-assisted pulsed laser evaporation of inorganic nanoparticles and organic/inorganic hybrid nanocomposites." AIP Conference Proceedings 1278 (2010): 812-823.
Source
scival
Published In
AIP Conference Proceedings
Volume
1278
Publish Date
2010
Start Page
812
End Page
823
DOI
10.1063/1.3507176

On the behaviour of Au plasmonic nanoparticles during hydrogen evolution at p-Si

Brewster Angle Reflectometry (BAR) and spectral photocurrent analysis show that Au nanoparticles are in a resonant state during light-induced hydrogen evolution with unpolarized light near-normal incidence. Keggin-type phosphododecamolybdate (PMo12O403-) anions were used as reducing and stabilizing agents to form novel Au nanoparticles (Au-NPs). BAR was employed to analyze the resonant optical response after adsorption to the surface of hydrogen terminated p-Si(111):H (1 × 1) and SiO2. Proton reduction in 1 M H2SO4 occurs at asymmetric Au-NPs where also multipole field effects influence the plasmonic behaviour. In a comparative discussion, the contribution of surface plasmon polariton excitation to the observed pronounced photocurrent enhancement is outlined. © 2010 Elsevier B.V.

Authors
Lublow, M; Skorupska, K; Zoladek, S; Kulesza, PJ; Vo-Dinh, T; Lewerenz, HJ
MLA Citation
Lublow, M, Skorupska, K, Zoladek, S, Kulesza, PJ, Vo-Dinh, T, and Lewerenz, HJ. "On the behaviour of Au plasmonic nanoparticles during hydrogen evolution at p-Si." Electrochemistry Communications 12.10 (2010): 1298-1301.
Source
scival
Published In
Electrochemistry Communications
Volume
12
Issue
10
Publish Date
2010
Start Page
1298
End Page
1301
DOI
10.1016/j.elecom.2010.07.004

A highly sensitive Raman method for selective cyanide detection based on evaporated cuprous iodide substrate

A strong interaction between cyanide anion and copper(i) cation in combination with non-resonant Raman fingerprinting allows the selective sensing of aqueous free cynanide with high sensitivity to parts per billion (ppb)-level. © The Royal Society of Chemistry 2010.

Authors
Reddy, CVG; Yan, F; Zhang, Y; Vo-Dinh, T
MLA Citation
Reddy, CVG, Yan, F, Zhang, Y, and Vo-Dinh, T. "A highly sensitive Raman method for selective cyanide detection based on evaporated cuprous iodide substrate." Analytical Methods 2.5 (2010): 458-460.
Website
http://hdl.handle.net/10161/4128
Source
scival
Published In
Analytical Methods: advancing methods and applications
Volume
2
Issue
5
Publish Date
2010
Start Page
458
End Page
460
DOI
10.1039/c0ay00085j

Plasmonic nanoparticles and nanowires: Design, fabrication and application in sensing

This study involves two aspects of our investigations of plasmonics-active systems: (i) theoretical and simulation studies and (ii) experimental fabrication of plasmonics-active nanostructures. Two types of nanostructures are selected as the model systems for their unique plasmonics properties: (1) nanoparticles and (2) nanowires on substrate. Special focus is devoted to regions where the electromagnetic field is strongly concentrated by the metallic nanostructures or between nanostructures. The theoretical investigations deal with dimers of nanoparticles and nanoshells using a semianalytical method based on a multipole expansion (ME) and the finite-element method (FEM) in order to determine the electromagnetic enhancement, especially at the interface areas of two adjacent nanoparticles. The experimental study involves the design of plasmonics-active nanowire arrays on substrates that can provide efficient electromagnetic enhancement in regions around and between the nanostructures. Fabrication of these nanowire structures over large chip-scale areas (from a few millimeters to a few centimeters) as well as FDTD simulations to estimate the EM fields between the nanowires are described. The application of these nanowire chips using surface-enhanced Raman scattering for detection of chemicals and labeled DNA molecules is described to illustrate the potential of the plasmonics chips for sensing. © 2010 American Chemical Society.

Authors
Vo-Dinh, T; Dhawan, A; Norton, SJ; Khoury, CG; Wang, H-N; Misra, V; Gerhold, MD
MLA Citation
Vo-Dinh, T, Dhawan, A, Norton, SJ, Khoury, CG, Wang, H-N, Misra, V, and Gerhold, MD. "Plasmonic nanoparticles and nanowires: Design, fabrication and application in sensing." Journal of Physical Chemistry C 114.16 (2010): 7480-7488.
Website
http://hdl.handle.net/10161/4077
PMID
24839505
Source
scival
Published In
The Journal of Physical Chemistry C
Volume
114
Issue
16
Publish Date
2010
Start Page
7480
End Page
7488
DOI
10.1021/jp911355q

Photoelectrocatalysis: Principles, nanoemitter applications and routes to bio-inspired systems

An overview on processes that are relevant in light-induced fuel generation, such as water photoelectrolysis or carbon dioxide reduction, is given. Considered processes encompass the photophysics of light absorption, excitation energy transfer to catalytically active sites and interfacial reactions at the catalyst/solution phase boundary. The two major routes envisaged for realization of photoelectrocatalytic systems, e.g. bio-inspired single photon catalysis and multiple photon inorganic or hybrid tandem cells, are outlined. For development of efficient tandem cell structures that are based on non-oxidic semiconductors, stabilization strategies are presented. Physical surface passivation is described using the recently introduced nanoemitter concept which is also applicable in photovoltaic (solid state or electrochemical) solar cells and first results with p-Si and p-InP thin films are presented. Solar-to-hydrogen efficiencies reach 12.1% for homoepitaxial InP thin films covered with Rh nanoislands. In the pursuit to develop biologically inspired systems, enzyme adsorption onto electrochemically nanostructured silicon surfaces is presented and tapping mode atomic force microscopy images of heterodimeric enzymes are shown. An outlook towards future envisaged systems is given. © 2010 The Royal Society of Chemistry.

Authors
Lewerenz, HJ; Heine, C; Skorupska, K; Szabo, N; Hannappel, T; Vo-Dinh, T; Campbell, SA; Klemm, HW; Muñoz, AG
MLA Citation
Lewerenz, HJ, Heine, C, Skorupska, K, Szabo, N, Hannappel, T, Vo-Dinh, T, Campbell, SA, Klemm, HW, and Muñoz, AG. "Photoelectrocatalysis: Principles, nanoemitter applications and routes to bio-inspired systems." Energy and Environmental Science 3.6 (2010): 748-760.
Website
http://hdl.handle.net/10161/4115
Source
scival
Published In
Energy & Environmental Science
Volume
3
Issue
6
Publish Date
2010
Start Page
748
End Page
760
DOI
10.1039/b915922n

Methodologies for developing surface-enhanced raman scattering (SERS) substrates for detection of chemical and biological molecules

This paper describes methodologies for developing efficient surface-enhanced Raman scattering (SERS) substrates such as annealing thin gold films for developing gold nanoislands, fabrication of nanopillars arrays and roughened films by employing focused ion beam (FIB) milling of gold films, as well as overcoating deep-UV-fabricated silicon nanowires with a layer of gold film. Excitation of surface plasmons in these gold nanostructures leads to substantial enhancement in the Raman scattering signal obtained from molecules lying in the vicinity of the nanostructure surface. In this paper, we perform comparative studies of SERS signals from molecules such as p-mercaptobenzoic acid and cresyl fast violet attached to or adsorbed on various gold SERS substrates. It was observed that gold-coated silicon nanowire substrates and annealed gold island substrates provided considerably higher SERS signals as compared to those from the FIB patterned substrates and planar gold films. The SERS substrates developed by the different processes were employed for detection of biological molecules such as dipicolinic acid, an excellent marker for spores of bacteria such as Anthrax. © 2010 IEEE.

Authors
Dhawan, A; Du, Y; Yan, F; Gerhold, MD; Misra, V; Vo-Dinh, T
MLA Citation
Dhawan, A, Du, Y, Yan, F, Gerhold, MD, Misra, V, and Vo-Dinh, T. "Methodologies for developing surface-enhanced raman scattering (SERS) substrates for detection of chemical and biological molecules." IEEE Sensors Journal 10.3 (2010): 608-616.
Source
scival
Published In
IEEE Sensors Journal
Volume
10
Issue
3
Publish Date
2010
Start Page
608
End Page
616
DOI
10.1109/JSEN.2009.2038634

Spectral filtering modulation method for estimation of hemoglobin concentration and oxygenation based on a single fluorescence emission spectrum in tissue phantoms.

PURPOSE: Hemoglobin concentration and oxygenation in tissue are important biomarkers that are useful in both research and clinical diagnostics of a wide variety of diseases such as cancer. The authors aim to develop simple ratiometric method based on the spectral filtering modulation (SFM) of fluorescence spectra to estimate the total hemoglobin concentration and oxygenation in tissue using only a single fluorescence emission spectrum, which will eliminate the need of diffuse reflectance measurements and prolonged data processing as required by most current methods, thus enabling rapid clinical measurements. METHODS: The proposed method consists of two steps. In the first step, the total hemoglobin concentration is determined by comparing a ratio of fluorescence intensities at two emission wavelengths to a calibration curve. The second step is to estimate oxygen saturation by comparing a double ratio that involves three emission wavelengths to another calibration curve that is a function of oxygen saturation for known total hemoglobin concentration. Theoretical derivation shows that the ratio in the first step is linearly proportional to the total hemoglobin concentrations and the double ratio in the second step is related to both total hemoglobin concentration and hemoglobin oxygenation for the chosen fiber-optic probe geometry. Experiments on synthetic fluorescent tissue phantoms, which included hemoglobin with both constant and varying oxygenation as the absorber, polystyrene spheres as scatterers, and flavin adenine dinucleotide as the fluorophore, were carried out to validate the theoretical prediction. RESULTS: Tissue phantom experiments confirm that the ratio in the first step is linearly proportional to the total hemoglobin concentration and the double ratio in the second step is related to both total hemoglobin concentrations and hemoglobin oxygenation. Furthermore, the relations between the two ratios and the total hemoglobin concentration and hemoglobin oxygenation are insensitive to the scattering property of the tissue model for the chosen probe geometry. CONCLUSIONS: A simple two-step ratiometric method based on the SFM of fluorescence spectra is proposed to estimate the total hemoglobin concentration and oxygenation in a tissue model using only a single fluorescence emission spectrum. This method is immune to the variation in system throughput caused by inconsistent optical coupling because of its ratiometric nature. Calibration curves are insensitive to the scattering coefficient for the chosen probe geometry. Moreover, since only fluorescence intensities at a few wavelengths in a single fluorescence emission spectrum are needed in this method, the SFM method minimizes the amount of required data and reduces the data acquisition time. Finally, since this method does not use nonlinear regression, it can dramatically save computation time in data processing. The high sensitivity of the proposed method to superficial tissue volumes makes it ideal for fluorescence based oximetry and medical diagnostics in applications such as early epithelial cancer diagnosis or wherever the measured tissue volume is exposed to the outside such as in open surgery.

Authors
Liu, Q; Vo-Dinh, T
MLA Citation
Liu, Q, and Vo-Dinh, T. "Spectral filtering modulation method for estimation of hemoglobin concentration and oxygenation based on a single fluorescence emission spectrum in tissue phantoms." Med Phys 36.10 (October 2009): 4819-4829.
PMID
19928112
Source
pubmed
Published In
Medical physics
Volume
36
Issue
10
Publish Date
2009
Start Page
4819
End Page
4829
DOI
10.1118/1.3218763

Plasmonics of 3-D nanoshell dimers using multipole expansion and finite element method.

The spatial and spectral responses of the plasmonic fields induced in the gap of 3-D nanoshell dimers of gold and silver are comprehensively investigated and compared via theory and simulation using the multipole expansion (ME) and the finite element method (FEM) in COMSOL, respectively. The E-field in the dimer gap was evaluated and compared as a function of shell thickness, interparticle distance, and size. The E-field increased with decreasing shell thickness, decreasing interparticle distance, and increasing size, with the error between the two methods ranging from 1 to 10%, depending on the specific combination of these three variables. This error increases several fold with increasing dimer size, as the quasi-static approximation breaks down. A consistent overestimation of the plasmon's fwhm and red shifting of the plasmon peak occurs with FEM, relative to ME, and it increases with decreasing shell thickness and interparticle distance. The size effect that arises from surface scattering of electrons is addressed and shown to be especially prominent for thin shells, for which significant damping, broadening, and shifting of the plasmon band is observed; the size effect also affects large nanoshell dimers, depending on their relative shell thickness, but to a lesser extent. This study demonstrates that COMSOL is a promising simulation environment to quantitatively investigate nanoscale electromagnetics for the modeling and designing of surface-enhanced Raman scattering (SERS) substrates.

Authors
Khoury, CG; Norton, SJ; Vo-Dinh, T
MLA Citation
Khoury, CG, Norton, SJ, and Vo-Dinh, T. "Plasmonics of 3-D nanoshell dimers using multipole expansion and finite element method." ACS Nano 3.9 (September 22, 2009): 2776-2788.
PMID
19678677
Source
pubmed
Published In
ACS Nano
Volume
3
Issue
9
Publish Date
2009
Start Page
2776
End Page
2788
DOI
10.1021/nn900664j

Plasmonics enhancement of a luminescent or Raman-active layer in a multilayered metallic nanoshell.

Expressions for the enhancement of the far-field scattering cross section of a luminescent or Raman-active compound contained within a multilayered nanosphere are derived, where the active compound resides between an outer metallic shell and a metallic core. The quasi-static approximation is assumed for silver and gold particles using a Lorentz-Drude model of the dielectric function. An attempt has also been made to account for the effect of electron scattering from the boundaries of the shell on the enhancement calculation.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Plasmonics enhancement of a luminescent or Raman-active layer in a multilayered metallic nanoshell." Appl Opt 48.27 (September 20, 2009): 5040-5049.
PMID
19767916
Source
pubmed
Published In
Applied Optics
Volume
48
Issue
27
Publish Date
2009
Start Page
5040
End Page
5049

Demonstration of surface-enhanced Raman scattering by tunable, plasmonic gallium nanoparticles.

Size-controlled gallium nanoparticles deposited on sapphire were explored as alternative substrates to enhance Raman spectral signatures. Gallium's resilience following oxidation is inherently advantageous in comparison with silver for practical ex vacuo nonsolution applications. Ga nanoparticles were grown using a simple molecular beam epitaxy-based fabrication protocol, and monitoring their corresponding surface plasmon resonance energy through in situ spectroscopic ellipsometry allowed the nanoparticles to be easily controlled for size. The Raman spectra obtained from cresyl fast violet (CFV) deposited on substrates with differing mean nanoparticle sizes represent the first demonstration of enhanced Raman signals from reproducibly tunable self-assembled Ga nanoparticles. Nonoptimized aggregate enhancement factors of approximately 80 were observed from the substrate with the smallest Ga nanoparticles for CFV dye solutions down to a dilution of 10 ppm.

Authors
Wu, PC; Khoury, CG; Kim, T-H; Yang, Y; Losurdo, M; Bianco, GV; Vo-Dinh, T; Brown, AS; Everitt, HO
MLA Citation
Wu, PC, Khoury, CG, Kim, T-H, Yang, Y, Losurdo, M, Bianco, GV, Vo-Dinh, T, Brown, AS, and Everitt, HO. "Demonstration of surface-enhanced Raman scattering by tunable, plasmonic gallium nanoparticles." J Am Chem Soc 131.34 (September 2, 2009): 12032-12033.
PMID
19655747
Source
pubmed
Published In
Journal of the American Chemical Society
Volume
131
Issue
34
Publish Date
2009
Start Page
12032
End Page
12033
DOI
10.1021/ja903321z

Applications of fiber-optics-based nanosensors to drug discovery.

BACKGROUND: Fiber-optic nanosensors are fabricated by heating and pulling optical fibers to yield sub-micron diameter tips and have been used for in vitro analysis of individual living mammalian cells. Immobilization of bioreceptors (e.g., antibodies, peptides, DNA) selective to targeting analyte molecules of interest provides molecular specificity. Excitation light can be launched into the fiber, and the resulting evanescent field at the tip of the nanofiber can be used to excite target molecules bound to the bioreceptor molecules. The fluorescence or surface-enhanced Raman scattering produced by the analyte molecules is detected using an ultra-sensitive photodetector. OBJECTIVE: This article provides an overview of the development and application of fiber-optic nanosensors for drug discovery. CONCLUSIONS: The nanosensors provide minimally invasive tools to probe subcellular compartments inside single living cells for health effect studies (e.g., detection of benzopyrene adducts) and medical applications (e.g., monitoring of apoptosis in cells treated with anticancer drugs).

Authors
Vo-Dinh, T; Scaffidi, J; Gregas, M; Zhang, Y; Seewaldt, V
MLA Citation
Vo-Dinh, T, Scaffidi, J, Gregas, M, Zhang, Y, and Seewaldt, V. "Applications of fiber-optics-based nanosensors to drug discovery." Expert Opin Drug Discov 4.8 (August 2009): 889-900.
PMID
23496274
Source
pubmed
Published In
Expert Opinion on Drug Discovery
Volume
4
Issue
8
Publish Date
2009
Start Page
889
End Page
900
DOI
10.1517/17460440903085112

Fabrication of nanodot plasmonic waveguide structures using FIB milling and electron beam-induced deposition.

Fabrication of metallic Au nanopillars and linear arrays of Au-containing nanodots for plasmonic waveguides is reported in this article by two different processes-focused ion beam (FIB) milling of deposited thin films and electron beam-induced deposition (EBID) of metallic nanostructures from an organometallic precursor gas. Finite difference time domain (FDTD) modeling of electromagnetic fields around metallic nanostructures was used to predict the optimal size and spacing between nanostructures useful for plasmonic waveguides. Subsequently, a multi-step FIB fabrication method was developed for production of metallic nanorods and nanopillars of the size and geometry suggested by the results of the FDTD simulations. Nanostructure fabrication was carried out on planar substrates including Au-coated glass, quartz, and mica slides as well as cleaved 4-mode optical fibers. In the second fabrication process, EBID was utilized for the development of similar nanostructures on planar Indium Tin Oxide and Titanium-coated glass substrates. Each method allows formation of nanostructures such that the plasmon resonances associated with the nanostructures could be engineered and precisely controlled by controlling the nanostructure size and shape. Linear arrays of low aspect ratio nanodot structures ranging in diameter between 50-70 nm were fabricated using EBID. Preliminary dark field optical microscopy demonstrates differences in the plasmonic response of the fabricated structures.

Authors
Dhawan, A; Gerhold, M; Madison, A; Fowlkes, J; Russell, PE; Vo-Dinh, T; Leonard, DN
MLA Citation
Dhawan, A, Gerhold, M, Madison, A, Fowlkes, J, Russell, PE, Vo-Dinh, T, and Leonard, DN. "Fabrication of nanodot plasmonic waveguide structures using FIB milling and electron beam-induced deposition." Scanning 31.4 (July 2009): 139-146.
PMID
19670460
Source
pubmed
Published In
Scanning - the Journal of Scanning Microscopies
Volume
31
Issue
4
Publish Date
2009
Start Page
139
End Page
146
DOI
10.1002/sca.20152

Comparison of FDTD numerical computations and analytical multipole expansion method for plasmonics-active nanosphere dimers.

This paper describes a comparative study of finite-difference time-domain (FDTD) and analytical evaluations of electromagnetic fields in the vicinity of dimers of metallic nanospheres of plasmonics-active metals. The results of these two computational methods, to determine electromagnetic field enhancement in the region often referred to as "hot spots" between the two nanospheres forming the dimer, were compared and a strong correlation observed for gold dimers. The analytical evaluation involved the use of the spherical-harmonic addition theorem to relate the multipole expansion coefficients between the two nanospheres. In these evaluations, the spacing between two nanospheres forming the dimer was varied to obtain the effect of nanoparticle spacing on the electromagnetic fields in the regions between the nanostructures. Gold and silver were the metals investigated in our work as they exhibit substantial plasmon resonance properties in the ultraviolet, visible, and near-infrared spectral regimes. The results indicate excellent correlation between the two computational methods, especially for gold nanosphere dimers with only a 5-10% difference between the two methods. The effect of varying the diameters of the nanospheres forming the dimer, on the electromagnetic field enhancement, was also studied.

Authors
Dhawan, A; Norton, SJ; Gerhold, MD; Vo-Dinh, T
MLA Citation
Dhawan, A, Norton, SJ, Gerhold, MD, and Vo-Dinh, T. "Comparison of FDTD numerical computations and analytical multipole expansion method for plasmonics-active nanosphere dimers." Opt Express 17.12 (June 8, 2009): 9688-9703.
PMID
19506618
Source
pubmed
Published In
Optics express
Volume
17
Issue
12
Publish Date
2009
Start Page
9688
End Page
9703

Multiplex detection of breast cancer biomarkers using plasmonic molecular sentinel nanoprobes.

We have demonstrated for the first time the feasibility of multiplex detection using the surface-enhanced Raman scattering-based molecular sentinel (MS) technology in a homogeneous solution. Two MS nanoprobes tagged with different Raman labels were used to detect the presence of the erbB-2 and ki-67 breast cancer biomarkers. The multiplexing capability of the MS technique was demonstrated by mixing the two MS nanoprobes and tested in the presence of single or multiple DNA targets.

Authors
Wang, H-N; Vo-Dinh, T
MLA Citation
Wang, H-N, and Vo-Dinh, T. "Multiplex detection of breast cancer biomarkers using plasmonic molecular sentinel nanoprobes." Nanotechnology 20.6 (February 11, 2009): 065101-.
PMID
19417369
Source
pubmed
Published In
Nanotechnology
Volume
20
Issue
6
Publish Date
2009
Start Page
065101
DOI
10.1088/0957-4484/20/6/065101

SERS-based plasmonic nanobiosensing in single living cells.

In this paper, we describe the development and application of a pH-sensitive plasmonics-active fiber-optic nanoprobe suitable for intracellular bioanalysis in single living human cells using surface-enhanced Raman scattering (SERS) detection. The effectiveness and usefulness of SERS-based fiber-optic nanoprobes are illustrated by measurements of intracellular pH in HMEC-15/hTERT immortalized "normal" human mammary epithelial cells and PC-3 human prostate cancer cells. The results indicate that fiber-optic nanoprobe insertion and interrogation provide a sensitive and selective means to monitor cellular microenvironments at the single cell level.

Authors
Scaffidi, JP; Gregas, MK; Seewaldt, V; Vo-Dinh, T
MLA Citation
Scaffidi, JP, Gregas, MK, Seewaldt, V, and Vo-Dinh, T. "SERS-based plasmonic nanobiosensing in single living cells." Anal Bioanal Chem 393.4 (February 2009): 1135-1141.
PMID
19066865
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
393
Issue
4
Publish Date
2009
Start Page
1135
End Page
1141
DOI
10.1007/s00216-008-2521-y

Scanning probe characterization of enzymes deposited onto step-bunched silicon nanostructures

Step-bunched Si surfaces with step heights of ∼3 nm have been prepared as substrates for immobilization of the enzyme reverse transcriptase of the avian myeloblastosis virus. Tapping mode atomic force microscopy has been used for imaging. Calibration experiments using the carrier solution without the enzyme show the preservation of the surface without organic contamination. Upon enzyme deposition, two specific shapes of the enzymes are observed to be adsorbed on the surface after rinsing with ultrapure water. Data analysis reveals that adsorption takes place at kink and reentrant sites on the surface and along step edges but not on the planar parts of the base (111) surface. The adsorption is interpreted by a combination of electrostatic and van der Waals interaction in accordance with the framework of the DLVONamed after Derjaguin, Landau, Verwey and Overbeek. theory. © 2009 The Royal Swedish Academy of Sciences.

Authors
Skorupska, K; Lewerenz, HJ; Vo-Dinh, T
MLA Citation
Skorupska, K, Lewerenz, HJ, and Vo-Dinh, T. "Scanning probe characterization of enzymes deposited onto step-bunched silicon nanostructures." Physica Scripta 79.6 (2009).
Source
scival
Published In
Physica Scripta: an international journal for experimental and theoretical physics
Volume
79
Issue
6
Publish Date
2009
DOI
10.1088/0031-8949/79/06/065801

Fiber optic SERS-based plasmonics nanobiosensing in single living cells

We describe the development of small molecule-sensitive plasmonics-active fiber-optic nanoprobes suitable for intracellular bioanalysis in single living human cells using surface-enhanced Raman scattering (SERS) detection. The practical utility of SERS-based fiber-optic nanoprobes is illustrated by measurements of intracellular pH in HMEC-15/hTERT immortalized "normal" human mammary epithelial cells and PC-3 human prostate cancer cells. The results indicate that fiber-optic nanoprobe insertion and interrogation provide a sensitive and selective means to monitor biologically-relevant small molecules at the single cell level. ©2009 SPIE.

Authors
Scaffidi, JP; Gregas, MK; Seewaldt, V; Dinh, TV
MLA Citation
Scaffidi, JP, Gregas, MK, Seewaldt, V, and Dinh, TV. "Fiber optic SERS-based plasmonics nanobiosensing in single living cells." Proceedings of SPIE - The International Society for Optical Engineering 7312 (2009).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
7312
Publish Date
2009
DOI
10.1117/12.824453

FIB/SEM fabrication of nanostructures for plasmonic sensors and waveguides

Authors
Madison, AC; Dhawan, A; Gerhold, M; Vo-Dinh, T; Russell, PE; Leonard, DN
MLA Citation
Madison, AC, Dhawan, A, Gerhold, M, Vo-Dinh, T, Russell, PE, and Leonard, DN. "FIB/SEM fabrication of nanostructures for plasmonic sensors and waveguides." Microscopy and Microanalysis 15.SUPPL. 2 (2009): 354-355.
Source
scival
Published In
Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada
Volume
15
Issue
SUPPL. 2
Publish Date
2009
Start Page
354
End Page
355
DOI
10.1017/S1431927609098894

Nano-biophotonics: From laboratory research to biomedical diagnostics

This lecture presents an overview of recent advances in the development of nano-biophotonic technologies including nanosensors and nanoprobes at the nexus of biology, medicine and nanotechnology [1]-[5]. This presentation describes two areas of research related to the development of nanoprobes and nanosensors for single-cell analysis and imaging: (1) plasmonics "molecular sentinel" nanoprobes using surface-enhanced Raman scattering (SERS) detection, and (2) nanosensors for in vivo analysis of a single cell for molecular diagnostics and imaging, and ultra-high throughput screening.

Authors
Tuan, V-D
MLA Citation
Tuan, V-D. "Nano-biophotonics: From laboratory research to biomedical diagnostics." 2009 1st Annual ORNL Biomedical Science and Engineering Conference, BSEC 2009 (2009).
Source
scival
Published In
2009 1st Annual ORNL Biomedical Science and Engineering Conference, BSEC 2009
Publish Date
2009
DOI
10.1109/BSEC.2009.5090465

Fabrication of metallic nanodot structures using focused ion beam (Fib) and electron Beam-induced deposition for plasmonic waveguides

Fabrication of a linear array of metallic nanodots and nanopillars for plasmonic waveguides is reported in this paper by two different processes - FIB milling of deposited thin films and electron beam-induced deposition of metallic nanostructures from a organometallic precursor gas introduced into the chamber. In the first FIB fabrication method, metallic nanorods and nanopillars were fabricated by depositing a 30-150 nm layer of a metallic (gold or silver) film on a planar substrate and subsequently employing FIB milling to pattern out the metallic nanopillars from the film. Employing FIB allowed formation of nanostructures such that the plasmon resonances associated with the nanostructures could be engineered and precisely controlled by controlling the nanostructure size and shape. Multistep FIB fabrication procedures were developed to form the nanostructures of complex geometries on planar substrates. The second fabrication processed used to create nanodots and nanopillars for plasmonic waveguides discussed in this paper is direct deposition of metal nanostructures, created when an electron beam (e-beam) is used to dissociate metal from an organometallic precursor gas in a predefined reaction region. Ionization energy required for decomposition of the Au precursor, i.e. Dimethyl Au (III) Fluoro Actylacetonate, is matched with that of the secondary electrons (between 5-50 eV) that are generated by exposing the substrate to a focused electron beam. © 2009 SPIE.

Authors
Dhawan, A; Gerhold, M; Russell, P; Vo-Dinh, T; Leonard, D
MLA Citation
Dhawan, A, Gerhold, M, Russell, P, Vo-Dinh, T, and Leonard, D. "Fabrication of metallic nanodot structures using focused ion beam (Fib) and electron Beam-induced deposition for plasmonic waveguides." Proceedings of SPIE - The International Society for Optical Engineering 7224 (2009).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
7224
Publish Date
2009
DOI
10.1117/12.809927

Fabrication of novel plasmonics-active substrates

This paper describes methodologies for fabricating of highly efficient plasmonics-active SERS substrates - having metallic nanowire structures with pointed geometries and sub-5 nm gap between the metallic nanowires enabling concentration of high EM fields in these regions - on a wafer-scale by a reproducible process that is compatible with large-scale development of these substrates. Excitation of surface plasmons in these nanowire structures leads to substantial enhancement in the Raman scattering signal obtained from molecules lying in the vicinity of the nanostructure surface. The methodologies employed included metallic coating of silicon nanowires fabricated by employing deep UV lithography as well as controlled growth of silicon germanium on silicon nanostructures to form diamond-shaped nanowire structures followed by metallic coating. These SERS substrates were employed for detecting chemical and biological molecules of interest. In order to characterize the SERS substrates developed in this work, we obtained SERS signals from molecules such as p-mercaptobenzoic acid (pMBA) and cresyl fast violet (CFV) attached to or adsorbed on the metal-coated SERS substrates. It was observed that both gold-coated triangular shaped nanowire substrates as well as gold-coated diamond shaped nanowire substrates provided very high SERS signals for the nanowires having sub-15 nm gaps and that the SERS signal depends on the closest spacing between the metal-coated silicon and silicon germanium nanowires. SERS substrates developed by the different processes were also employed for detection of biological molecules such as DPA (Dipicolinic Acid), an excellent marker for spores of bacteria such as Anthrax. © 2009 SPIE.

Authors
Dhawana, A; Gerholda, M; Duc, Y; Misrac, V; Vo-Dinh, T
MLA Citation
Dhawana, A, Gerholda, M, Duc, Y, Misrac, V, and Vo-Dinh, T. "Fabrication of novel plasmonics-active substrates." Proceedings of SPIE - The International Society for Optical Engineering 7205 (2009).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
7205
Publish Date
2009
DOI
10.1117/12.809887

Optical response of linear chains of metal nanospheres and nanospheroids.

A semi-analytical method for computing the electric field surrounding a finite linear chain of metal nanospheres and nanospheroids is described. In treating chains or clusters of spheres, a common approach is to use the spherical-harmonic addition theorem to relate the multipole expansion coefficients between different spheres. A method is described here that avoids the use of spherical-harmonic addition theorems, which are not applicable to spheroidal chains. Simulations are given that illustrate the large field enhancements that can occur in the gaps between silver nanoparticles arising from plasmon resonances.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Optical response of linear chains of metal nanospheres and nanospheroids." J Opt Soc Am A Opt Image Sci Vis 25.11 (November 2008): 2767-2775.
PMID
18978855
Source
pubmed
Published In
Journal of the Optical Society of America A
Volume
25
Issue
11
Publish Date
2008
Start Page
2767
End Page
2775

Apoferritin protein cages: a novel drug nanocarrier for photodynamic therapy.

A methylene blue-encapsulated apoferritin complex shows cytotoxic effects on MCF-7 human breast adenocarcinoma cells when irradiated at the appropriate wavelength.

Authors
Yan, F; Zhang, Y; Yuan, H-K; Gregas, MK; Vo-Dinh, T
MLA Citation
Yan, F, Zhang, Y, Yuan, H-K, Gregas, MK, and Vo-Dinh, T. "Apoferritin protein cages: a novel drug nanocarrier for photodynamic therapy." Chem Commun (Camb) 38 (October 14, 2008): 4579-4581.
PMID
18815689
Source
pubmed
Published In
Chemical Communications
Issue
38
Publish Date
2008
Start Page
4579
End Page
4581
DOI
10.1039/b810949d

Modeling of nonphase mechanisms in ultrasonic modulation of light propagation.

While phase variation due to ultrasonic modulation of coherent light has been extensively studied in acousto-optical imaging, fewer groups have studied nonphase mechanisms of ultrasonic modulation, which may be important in exploring ultrasonic modulation of incoherent light for imaging. We have developed a versatile Monte Carlo based method that can model not only phase variation due to refractive index changes and scatterer displacement in tissue or tissue-like phantoms, but also amplitude and exit location variations due to the changes in optical properties and refractive index under ultrasonic modulation, in which the exit location variation has not, to the best of our knowledge, been modeled previously. Our results show that the modulation depth due to the exit location variation is three orders of magnitude higher than that due to amplitude variation, but two to three orders of magnitude lower than that due to phase variation for monochromatic light. Furthermore it is found that the modulation depth in reflectance due to the exit location variation is larger than that in transmittance for small source-detector separations.

Authors
Liu, Q; Norton, S; Vo-Dinh, T
MLA Citation
Liu, Q, Norton, S, and Vo-Dinh, T. "Modeling of nonphase mechanisms in ultrasonic modulation of light propagation." Appl Opt 47.20 (July 10, 2008): 3619-3630.
PMID
18617978
Source
pubmed
Published In
Applied Optics
Volume
47
Issue
20
Publish Date
2008
Start Page
3619
End Page
3630

Intensified biochip system using chemiluminescence for the detection of Bacillus globigii spores.

This paper reports the first intensified biochip system for chemiluminescence detection and the feasibility of using this system for the analysis of biological warfare agents is demonstrated. An enzyme-linked immunosorbent assay targeting Bacillus globigii spores, a surrogate species for Bacillus anthracis, using a chemiluminescent alkaline phosphatase substrate is combined with a compact intensified biochip detection system. The enzymatic amplification was found to be an attractive method for detection of low spore concentrations when combined with the intensified biochip device. This system was capable of detecting approximately 1 x 10(5) Bacillus globigii spores. Moreover, the chemiluminescence method, combined with the self-contained biochip design, allows for a simple, compact system that does not require laser excitation and is readily adaptable to field use.

Authors
Stratis-Cullum, DN; Griffin, GD; Mobley, J; Vo-Dinh, T
MLA Citation
Stratis-Cullum, DN, Griffin, GD, Mobley, J, and Vo-Dinh, T. "Intensified biochip system using chemiluminescence for the detection of Bacillus globigii spores." Anal Bioanal Chem 391.5 (July 2008): 1655-1660.
PMID
18224472
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
391
Issue
5
Publish Date
2008
Start Page
1655
End Page
1660
DOI
10.1007/s00216-008-1835-0

Silver nanoparticle-doped polyvinyl alcohol coating as a medium for surface-enhanced Raman scattering analysis.

A simple polymer substrate for inducing Surface-Enhanced Raman Scattering (SERS) has been investigated. This SERS substrate consists of a solid support, such as a glass slide covered with polyvinyl alcohol (PVA) impregnated with fine silver nanoparticles. The preparation simply involves mixing aqueous PVA polymer with solid AgNO3 to produce a solution that can be easily spin coated on the glass substrate and dried to obtain a hard translucent coating. Aqueous solution of FeSO4.7H2O was used to reduce Ag+ ions to silver nanoparticles. The effects of various experimental conditions of sample preparation were investigated in order to improve the Raman enhancement efficiency of the substrate. The overall substrate performance was evaluated with the use of biologically important compounds: benzoic acid, p-amino benzoic acid, pyridine and dopamine. The spectral features of these compounds closely matched with those reported in literature. The use of the polymer matrix made the SERS substrate resistant to scratching, therefore, improving it to be more suitable for field applications. The hydrophilic nature of the polymer provides additional advantages for probing biological samples. The shelf-life of the dried, unreduced substrates is at least one month.

Authors
Karabiçak, S; Kaya, M; Vo-Dinh, T; Volkan, M
MLA Citation
Karabiçak, S, Kaya, M, Vo-Dinh, T, and Volkan, M. "Silver nanoparticle-doped polyvinyl alcohol coating as a medium for surface-enhanced Raman scattering analysis." J Nanosci Nanotechnol 8.2 (February 2008): 955-960.
PMID
18464433
Source
pubmed
Published In
Journal of nanoscience and nanotechnology
Volume
8
Issue
2
Publish Date
2008
Start Page
955
End Page
960

Photodynamic therapy of Barrett's esophagus: ablation of Barrett's mucosa and reduction in p53 protein expression after treatment.

BACKGROUND: The effectiveness of photodynamic therapy (PDT) for ablation of high grade dysplasia (HGD) in Barrett's esophagus (BE) is typically reported histologically. Following successful PDT, Barrett's mucosa is replaced with neosquamous mucosa. The objective of this study was to compare the expression of p53 protein in neosquamous mucosa as compared to that in HGD samples not treated with PDT. PATIENTS AND METHODS: The patients were divided into two groups. Group I patients (n = 12) had been treated with PDT for HGD and provided 23 biopsy samples of neosquamous mucosa. Group II patients (n = 10) had not received any ablative therapies for BE and provided 14 HGD samples. The immunohistochemical (IHC) staining for p53 protein was performed using mouse anti-human monoclonal antibody DO-1. The degree of p53 protein expression in the cell nuclei was scored using an established IHC scoring system (0 for negative samples and range of 2 to 8 for positive samples). RESULTS: The HGD samples showed diffuse strong p53 staining. The median IHC score for HGD was 7.0. The median IHC score for neosquamous mucosa following PDT was 4.0, with positive scores indicating weak staining in the basal layer of the neosquamous samples. There was significantly lower p53 expression in the neosquamous samples compared to that in the HGD samples (p < 0.001). CONCLUSION: Significantly lower p53 protein expression was detected in neosquamous mucosa of patients who had received PDT for HGD, suggesting a decreased risk for neoplastic progression after treatment.

Authors
Panjehpour, M; Coppola, D; Overholt, BF; Vo-Dinh, T; Overholt, S
MLA Citation
Panjehpour, M, Coppola, D, Overholt, BF, Vo-Dinh, T, and Overholt, S. "Photodynamic therapy of Barrett's esophagus: ablation of Barrett's mucosa and reduction in p53 protein expression after treatment." Anticancer Res 28.1B (January 2008): 485-489.
PMID
18383889
Source
pubmed
Published In
Anticancer research
Volume
28
Issue
1B
Publish Date
2008
Start Page
485
End Page
489

Fiberoptics Nanosensing at the Single Cell Level

Authors
Vo Dinh, T
MLA Citation
Vo Dinh, T. "Fiberoptics Nanosensing at the Single Cell Level." Spectrochimia Acta B 63 (2008): 95-103. (Academic Article)
Source
manual
Published In
Spectrochimia Acta B
Volume
63
Publish Date
2008
Start Page
95
End Page
103

Nanosensing at the single cell level

This article presents an overview of the development, operation, and applications of optical nanobiosensors for use in in vivo detection of biotargets in individual living cells. The nanobiosensors are equipped with immobilized bioreceptor probes (e.g., antibodies, enzyme substrate) selective to specific molecular targets. Laser excitation is transmitted into the fiber producing an evanescent field at the tip of the fiber in order to excite target molecules bound to the bioreceptors immobilized at the fiber tips. A photometric system detects the optical signal (e.g., fluorescence) originated from the analyte molecules or from the analyte-bioreceptor reaction. Examples of detection of biospecies and molecular signaling pathways of apoptosis in a living cell are discussed to illustrate the potential of the nanobiosensor technology for single cell analysis. © 2007.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Nanosensing at the single cell level." Spectrochimica Acta - Part B Atomic Spectroscopy 63.2 (2008): 95-103.
PMID
24839348
Source
scival
Published In
Spectrochimica Acta Part B: Atomic Spectroscopy
Volume
63
Issue
2
Publish Date
2008
Start Page
95
End Page
103
DOI
10.1016/j.sab.2007.11.027

Focus on bioanalysis

The guest editors of Analytical and Bioanalytical Chemistry (ABC) invited scientific professionals, to submit review papers on new developments in bioanalysis. The guest editors reviewed articles related to detection principles, surveying immunoassays and their application to high-throughput screening and microarrays. ABC has published many articles on the application of Lab-on-a-chip developments, biosensors, and microarrays. The direct optical detection technique has gained significant interest in monitoring interaction process among proteins and cells. Environmental analysis, safety and security, process control, molecular and medical diagnostics, and cell morphology are the new emerging research fields in bioanalysis. These new fields are expected to help in the development of diagnostics testing, medical care, homecare, process control, and pollutant detection in future.

Authors
Gauglitz, G; Scheller, FW; Vo-Dinh, T
MLA Citation
Gauglitz, G, Scheller, FW, and Vo-Dinh, T. "Focus on bioanalysis." Analytical and Bioanalytical Chemistry 391.5 (2008): 1483-1484.
Source
scival
Published In
Analytical and Bioanalytical Chemistry
Volume
391
Issue
5
Publish Date
2008
Start Page
1483
End Page
1484
DOI
10.1007/s00216-008-2159-9

Gold nanostars for surface-enhanced Raman scattering: synthesis, characterization and optimization

The controlled synthesis of high-yield gold nanostars of varying sizes, their characterization, and their use in surface-enhanced Raman scattering (SERS) measurements are reported for the first time. Gold nanostars ranging from 45 to 116 nm in size were synthesized in high yield, geometrically and statistically modeled, and optically characterized using transmission and scanning electron microscopy and UV-visible absorption spectroscopy. The nanostar characterization involved studying both morphology evolution over time and size as a function of nucleation (injected seed volume). The nanostar properties as substrates for SERS were investigated and compared with respect to size. As the overall star size increases, so does the core size, the number of branches and branch aspect ratio; the number of branch tips per star surface area decreases with increasing size. The stars become more inhomogeneous in shape, although their yield is high and overall size remains homogeneous. Variations in star size are also accompanied by shifts of the long plasmon band in the NIR region, which hints toward tuning capabilities that may be exploited in specific SERS applications. The measured SERS enhancement factors suggest an interesting correlation between nanostar size and SERS efficiencies and were relatively consistent across different star samples, with the enhancement factor estimated as 5 × 103 averaged over the 52-nm nanostars for 633-nm excitation. © 2008 American Chemical Society.

Authors
Khoury, CG; Vo-Dinh, T
MLA Citation
Khoury, CG, and Vo-Dinh, T. "Gold nanostars for surface-enhanced Raman scattering: synthesis, characterization and optimization." Journal of Physical Chemistry C 112.48 (2008): 18849-18859.
Source
scival
Published In
The Journal of Physical Chemistry C
Volume
112
Issue
48
Publish Date
2008
Start Page
18849
End Page
18859
DOI
10.1021/jp8054747

Nanobiosensing using plasmonic nanoprobes

This paper provides an overview of the development and applications of plasmonics-active nanoprobes in biomedical diagnostics. Specific examples of detection techniques using surface-enhanced Raman scattering are presented to illustrate the usefulness and potential of the plasmonics nanoprobes for gene detection and nanobiosensing. The detection of specific target deoxyribonucleic acids sequences using a novel "molecular sentinel" nanoprobe method is presented and discussed in detail. © 2008 IEEE.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Nanobiosensing using plasmonic nanoprobes." IEEE Journal on Selected Topics in Quantum Electronics 14.1 (2008): 198-205.
PMID
24839386
Source
scival
Published In
IEEE Journal of Selected Topics in Quantum Electronics
Volume
14
Issue
1
Publish Date
2008
Start Page
198
End Page
205
DOI
10.1109/JSTQE.2007.914738

Focused in beam fabrication of metallic nanostructures on end faces of optical fibers for chemical sensing applications

Focused ion beam (FIB) fabrication of fiber optic sensors, mainly chemical sensors, which are based on plasmonics-active nanostructures formed on the cleaved tips of optical fibers, is reported. The nanostructures fabricated included nanoholes in optically thick metallic films as well as metallic nanopillars and nanorods. The sensing mechanism is based on detecting shifts in surface plasmon resonances (SPRs) associated with nanoholes in metallic films and localized SPRs of metallic nanopillars and nanorods, when the refractive index of the medium surrounding the nanostructures is changed. These sensors can be employed for the detection of chemical agents in air as well as liquid media surrounding the sensors. FIB milling was employed to fabricate ordered arrays of nanoholes in optically thick (100-240 nm) metallic films deposited on cleaved end faces of multimode, four-mode, and single-mode optical fibers. Separately, metallic nanorods and nanopillars were formed by first depositing a metallic (gold or silver) film on tips of optical fibers, which was followed by FIB milling large area patterns to form freestanding nanorods and nanopillars. Utilizing FIB allows engineering nanostructure geometries, i.e., nanostructure shapes and sizes that are chosen based on the plasmon resonances associated with them. Formation of periodic arrays of nanoholes provides a means of tuning plasmon resonance peaks, associated with extraordinary transmission of light through the array of nanoholes in the metallic films, based on periodicity and shape of the nanoholes as well as on refractive index changes to form sensitive chemical sensors. © 2008 American Vacuum Society.

Authors
Dhawan, A; Muth, JF; Leonard, DN; Gerhold, MD; Gleeson, J; Vo-Dinh, T; Russell, PE
MLA Citation
Dhawan, A, Muth, JF, Leonard, DN, Gerhold, MD, Gleeson, J, Vo-Dinh, T, and Russell, PE. "Focused in beam fabrication of metallic nanostructures on end faces of optical fibers for chemical sensing applications." Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures 26.6 (2008): 2168-2173.
PMID
23976838
Source
scival
Published In
Journal of vacuum science & technology. B, Microelectronics and nanometer structures : processing, measurement, and phenomena : an official journal of the American Vacuum Society
Volume
26
Issue
6
Publish Date
2008
Start Page
2168
End Page
2173
DOI
10.1116/1.3013329

Spectral bounds on plasmon resonances for Ag and Au prolate and oblate nanospheroids

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Spectral bounds on plasmon resonances for Ag and Au prolate and oblate nanospheroids." JOURNAL OF NANOPHOTONICS 2 (2008).
PMID
23977404
Source
wos-lite
Published In
Journal of Nanophotonics
Volume
2
Publish Date
2008
DOI
10.1117/1.3001731

Fabrication of fiber-optic sensors based on plasmon resonances of metallic nanostructures

This paper describes the fabrication of portable and robust fiber optic sensors - mainly chemical and biological sensors - on standard communication grade optical fibers. Metallic nanostructures such as nanoparticles, nanopillars, nanorods, and nanoholes in optically thick metallic films were employed to precisely control the enhancement and absorption of light so as to form sensitive and specific optical sensors based on optical fibers. The fiber-optic sensors employ localized plasmon resonances (LSPRs) of metallic nanostructures formed on the fiber end-face as well as surface plasmon resonances associated with nanoholes in optically thick metallic films as a means of transducing the input optical signal. These metallic nanostructures were formed on the cleaved end-face of multimode and single mode optical fibers and were employed in both reflection and transmission modes. Metallic nanoparticles, nanorods, and nanopillars were formed on the tip or surface of the optical fiber by either employing chemical means or by first depositing a 10-200 nm layer of metallic film on the tip of the fiber and then employing focused ion beam (FIB) milling to pattern out the metallic nanoparticles and nanopillars from the film. Ordered arrays of nanoholes were formed in optically thick (150-230 nm) metallic films by employing FIB milling. Gold (Au) nanostructures are chemically stable and result in plasmon resonance related dips in the transmission spectrum in the visible spectral region. Hence, gold was selected as the material of choice for the fabrication of the plasmon resonance sensors. © The Electrochemical Society.

Authors
Dhawan, A; Gerhold, M; Marinakos, S; Leonard, D; Wang, H-N; Chilkoti, A; Russell, P; Vo-Dinh, T
MLA Citation
Dhawan, A, Gerhold, M, Marinakos, S, Leonard, D, Wang, H-N, Chilkoti, A, Russell, P, and Vo-Dinh, T. "Fabrication of fiber-optic sensors based on plasmon resonances of metallic nanostructures." ECS Transactions 11.14 (2008): 41-55.
Source
scival
Published In
ECS Transactions
Volume
11
Issue
14
Publish Date
2008
Start Page
41
End Page
55
DOI
10.1149/1.2902314

Development of plasmonics-active SERS substrates on a wafer scale for chemical and biological sensing applications

This paper describes the fabrication of highly efficient plasmonics-active SERS substrates - having metallic nanowire structures with pointed geometries and sub-5 nm gap between the metallic nanowires enabling concentration of high EM fields in these regions - on a wafer-scale by a reproducible process that is compatible with large-scale development of these substrates. These SERS substrates were employed for detecting chemical and biological molecules of interest.

Authors
Dhawan, A; Du, Y; Wang, H; Leonard, D; Misra, V; Ozturk, M; Gerhold, M; Vo-Dinh, T
MLA Citation
Dhawan, A, Du, Y, Wang, H, Leonard, D, Misra, V, Ozturk, M, Gerhold, M, and Vo-Dinh, T. "Development of plasmonics-active SERS substrates on a wafer scale for chemical and biological sensing applications." Technical Digest - International Electron Devices Meeting, IEDM (2008).
Source
scival
Published In
Technical Digest - International Electron Devices Meeting
Publish Date
2008
DOI
10.1109/IEDM.2008.4796732

Nanosensors and nanoprobes for environmental health sensing and biomedical screening

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Nanosensors and nanoprobes for environmental health sensing and biomedical screening." LEOS Summer Topical Meeting (2008): 59-60.
Source
scival
Published In
LEOS Summer Topical Meeting
Publish Date
2008
Start Page
59
End Page
60
DOI
10.1109/LEOSST.2008.4590488

Computational design of FIB-milled nanostructures for use in biosensing

Authors
Gerhold, M; Dhawan, A; Vo-Dinh, T
MLA Citation
Gerhold, M, Dhawan, A, and Vo-Dinh, T. "Computational design of FIB-milled nanostructures for use in biosensing." LEOS Summer Topical Meeting (2008): 63-64.
Source
scival
Published In
LEOS Summer Topical Meeting
Publish Date
2008
Start Page
63
End Page
64
DOI
10.1109/LEOSST.2008.4590490

Modeling of amplitude and exit location variations of light propagation under ultrasonic modulation

While phase variation due to ultrasonic modulation of coherent light has been extensively studied in acousto-optical imaging, fewer groups have studied non-phase mechanisms of ultrasonic modulation, which may be important in exploring ultrasonic modulation of incoherent light for imaging. We have developed a versatile Monte Carlo based method that can model not only phase variation due to refractive index changes and scatterer displacement, but also amplitude and exit location variations due to the changes in optical properties and refractive index under ultrasonic modulation, in which the exit location variation has not been modeled previously to our knowledge. Our results show that the modulation depth due to the exit location variation is one to two orders of magnitude higher than that due to amplitude variation, but two to three orders of magnitude lower than that due to phase variation for monochromatic light. Furthermore, it is found that the modulation depth in reflectance due to the exit location variation is larger than that in transmittance for small source-detector separations.

Authors
Liu, Q; Norton, S; Vo-Dinh, T
MLA Citation
Liu, Q, Norton, S, and Vo-Dinh, T. "Modeling of amplitude and exit location variations of light propagation under ultrasonic modulation." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 6856 (2008).
Source
scival
Published In
Proceedings of SPIE
Volume
6856
Publish Date
2008
DOI
10.1117/12.762326

Theoretical modeling of plasmon resonances: Effect of aspect ratio in spheroidal nanoshells

Plasmon resonances are computed for prolate spheroidal nanoshells. Both longitudinal and transverse resonances are investigated as a function of aspect ratio. Formulas for the surface charge density on the outside and inside shell surfaces are derived.

Authors
Norton, SJ; Dhawan, A; Gerhold, MD; Vo-Dinh, T
MLA Citation
Norton, SJ, Dhawan, A, Gerhold, MD, and Vo-Dinh, T. "Theoretical modeling of plasmon resonances: Effect of aspect ratio in spheroidal nanoshells." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 6869 (2008).
Source
scival
Published In
Proceedings of SPIE
Volume
6869
Publish Date
2008
DOI
10.1117/12.779203

Nano-engineered surface-enhanced Raman scattering (SERS) substrates with patterned structures on the distal end of optical fibers

This paper describes the development of fiber optic sensor probes and planar substrates containing patterned nanostructures such as nanoholes in gold films, as well as gold nanoparticles, nano-pillars, nanorods, and nano-islands. Several methods of producing gold nanofeatures on fiber tips and planar substrates were investigated such as annealing of thin gold films and focused ion beam (FIB) milling. A Hitachi FB-2100 FIB milling machine with a gallium ion source was employed to form the nanoparticles from 20-100 nm gold films deposited on the fiber tip. Nano-engineered gold features were also formed by coating planar substrates and fiber tips with thin gold films (4-10 nm) and annealing these thin films. Excitation of surface plasmons in gold nanostructures leads to substantial enhancement in the Raman scattering signal obtained from molecules attached to the nanostructure surface. In this work, a comparison was made between the SERS signals obtained from the gold substrates developed by employing the different procedures mentioned above. Fiber samples and planar substrates with these nanostructures were coated with SERS active dyes such as p-mercaptobenzoic acid (pMBA) and cresyl fast violet (CFV). It was observed that the SERS signal obtained from these gold nanofeatures was much higher than that obtained from a continuous gold film and that the SERS enhancement was shape and size dependent.

Authors
Dhawan, A; Zhang, Y; Yan, F; Gerhold, M; Vo-Dinh, T
MLA Citation
Dhawan, A, Zhang, Y, Yan, F, Gerhold, M, and Vo-Dinh, T. "Nano-engineered surface-enhanced Raman scattering (SERS) substrates with patterned structures on the distal end of optical fibers." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 6869 (2008).
Source
scival
Published In
Proceedings of SPIE
Volume
6869
Publish Date
2008
DOI
10.1117/12.763879

Detection of multidrug-resistant tuberculosis gene using plasmonics nanoprobes

This paper describes the use of plasmonics-based nanoprobes for detection of multidrug-resistant tuberculosis gene. The plasmonics nanoprobe is composed of a silver nanoparticle pre-coated with a stem-loop DNA probe that is tagged with a Raman label at one end of the stem region, while the other end of the probe is covalently conjugated to the nanoparticle via a thiol-silver bond. The loop region is designed to detect a specific target gene sequence. In the absence of target, the Raman label is in close proximity to the metal surface, resulting in an intense SERS signal upon laser excitation. In the presence of the target DNA sequence, hybridization between the target and probe disrupts the stem-loop configuration, separating the Raman label from the metal surface and quenching the SERS signal. In this study, we successfully demonstrated for the first time the feasibility of using plasmonics nanoprobes for the detection of multidrug-resistant tuberculosis gene.

Authors
Wang, H-N; Yan, F; Zhang, Y; Vo-Dinh, T
MLA Citation
Wang, H-N, Yan, F, Zhang, Y, and Vo-Dinh, T. "Detection of multidrug-resistant tuberculosis gene using plasmonics nanoprobes." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 6869 (2008).
Source
scival
Published In
Proceedings of SPIE
Volume
6869
Publish Date
2008
DOI
10.1117/12.761897

Geometry-dependent plasmon resonances of metallic nanostructures for enhancement of localized electromagnetic fields around the nanostructures

This paper describes theoretical and experimental evaluations of electromagnetic fields around metallic nanostructures, such as nanorods, nano-pillars, and a collection of nanorods separated by nano-scale distances. Nanostructures having different sizes and shapes were evaluated. The spacing between nanorods and elliptical nanopillars was varied such that the effect of nanoparticle spacing on the electromagnetic fields in the regions between the nanostructures could be studied. Gold was the metal employed in our work as it demonstrates substantial plasmon excitation and is chemically stable. Calculations of the electromagnetic fields in the vicinity of the different metallic nanostructures were made by employing Finite Difference Time Domain (FDTD). Refractive index of the media surrounding the nanostructures was varied for these calculations. These calculations were carried out at different wavelengths in the visible and near-infrared spectral regimes. In order to fabricate these nanostructures on silica substrates, focused ion beam (FIB) milling was employed. These structures were fabricated on gold-coated planar silica and mica substrates and tips of four mode and multimode optical fibers. In our experimental evaluations of the different metallic nanostructures, surface enhanced Raman scattering (SERS) signals from the different metallic nanostructures were obtained and were correlated to the spacing distance between the different metallic nanostructures.

Authors
Gerhold, M; Dhawan, A; Vo-Dinh, T
MLA Citation
Gerhold, M, Dhawan, A, and Vo-Dinh, T. "Geometry-dependent plasmon resonances of metallic nanostructures for enhancement of localized electromagnetic fields around the nanostructures." Proceedings of SPIE - The International Society for Optical Engineering 6902 (2008).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
6902
Publish Date
2008
DOI
10.1117/12.771440

Plasmonic SERS molecular sentinels: A new biosensing approach

This chapter describes the detection of specific target DNA sequences using a novel 'molecular sentinel' (MS) biosensing approach using surface-enhanced Raman scattering (SERS) detection. The SERS-based MS nanoprobe consists of a metal nanoparticle and a stem-loop DNA molecule tagged with a Raman label. The nanoprobe utilizes the specificity and selectivity of the DNA hairpin probe sequence to detect a specific target DNA sequence of interest. In the normal configuration and in the absence of target DNA, the stem-loop configuration maintains the Raman label in close proximity to the metal nanoparticle, inducing an intense SERS effect that produces a strong Raman signal upon laser excitation. Upon hybridization of a complementary target DNA sequence to the nanoprobe, the stem-loop configuration is disrupted, causing the Raman label to physically separate from the metal nanoparticle, thus quenching the SERS signal. Due to the possibility of performing simple homogeneous bioassays, the SERS-MSs provide useful diagnostic probes for multiple biological targets. The potential for combining the spectral selectivity and high sensitivity of the SERS process with inherent molecular specificity of MS nanoprobes to diagnose molecular target sequences is discussed. © 2008 Elsevier B.V. All rights reserved.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Plasmonic SERS molecular sentinels: A new biosensing approach." Optical Biosensors (2008): 385-399.
Source
scival
Published In
Optical Biosensors
Publish Date
2008
Start Page
385
End Page
399
DOI
10.1016/B978-044453125-4.50010-3

Biosensors and biochips

This chapter provides an overview of the various types of biosensors and biochips that have been developed for biological and medical applications, along with significant advances and over the last several years in these technologies. Various classification schemes that can be used for categorizing the different biosensor and biochip systems are also discussed. © 2007 Springer Science+Business Media, LLC.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Biosensors and biochips." 4 (December 1, 2007): 3-20. (Chapter)
Source
scopus
Volume
4
Publish Date
2007
Start Page
3
End Page
20
DOI
10.1007/978-0-387-25845-4_1

Development of a synchronous fluorescence imaging system and data analysis methods.

Although conventional autofluorescence spectroscopy, in which fluorescence emission spectra are recorded for fixed excitation wavelengths, has demonstrated good performance in tissue diagnosis, it suffers from prolonged data acquisition time and broad-band fluorescence features. Synchronous spectroscopy has been proposed to overcome the limitations of conventional fluorescence spectroscopy but has not been applied to imaging for tissue diagnosis in vivo. Our group has developed a synchronous fluorescence imaging system to combine the great diagnostic potential of synchronous spectroscopy and the large field of view of imaging for cancer diagnosis. This system has been tested in a mouse skin model to capture synchronous fluorescence images. A simple discriminant analysis method and a more complicated multi-variate statistical method have been developed to generate a single diagnostic image from a large number of raw fluorescence images. Moreover, it was demonstrated that the diagnostic image generated from synchronous data is comparable to that generated from full spectral data in classification accuracy.

Authors
Liu, Q; Chen, K; Martin, M; Wintenberg, A; Lenarduzzi, R; Panjehpour, M; Overholt, BF; Vo-Dinh, T
MLA Citation
Liu, Q, Chen, K, Martin, M, Wintenberg, A, Lenarduzzi, R, Panjehpour, M, Overholt, BF, and Vo-Dinh, T. "Development of a synchronous fluorescence imaging system and data analysis methods." Opt Express 15.20 (October 1, 2007): 12583-12594.
PMID
19550526
Source
pubmed
Published In
Optics express
Volume
15
Issue
20
Publish Date
2007
Start Page
12583
End Page
12594

Imaging the distribution of magnetic nanoparticles with ultrasound.

Magnetic nanoparticles can be caused to oscillate under the influence of an incident ultrasonic wave. If the particles are momentarily aligned with a magnetizing pulse creating a macroscopic magnetization, this oscillation will result in a time-varying magnetic moment which should be detectable as an induced voltage in a nearby pickup coil. In this way, focused ultrasound can be used to map, or image, the spatial distribution of the magnetic particles after these particles have been introduced into the body. The magnetic particles could be antibody-labeled to target tumor cells or used as a cardiovascular contrast agent, among other applications. The magnitude of the induced signal is estimated for one micron particles with a Fe/tissue volume fraction of 10(-6), which is about the limit of detectability for MRI superparamagnetic contrast agents consisting of single domain iron-oxide particles. One advantage of this method compared to conventional MRI is potentially greater sensitivity due to the absence of a large background signal.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Imaging the distribution of magnetic nanoparticles with ultrasound." IEEE Trans Med Imaging 26.5 (May 2007): 660-665.
PMID
17518060
Source
pubmed
Published In
IEEE Transactions on Medical Imaging
Volume
26
Issue
5
Publish Date
2007
Start Page
660
End Page
665
DOI
10.1109/TMI.2007.895476

Extracting intrinsic synchronous fluorescence for spectral imaging

A ratio-metric method was proposed to extract intrinsic fluorescence from synchronous fluorescence spectra distorted by absorption and scattering. Its applicable range was investigated using Monte Carlo simulations and the accuracy was tested with phantom experiments. © 2007 Optical Society of America.

Authors
Liu, Q; Vo-Dinh, T
MLA Citation
Liu, Q, and Vo-Dinh, T. "Extracting intrinsic synchronous fluorescence for spectral imaging." Optics InfoBase Conference Papers (January 1, 2007).
Source
scopus
Published In
Optics InfoBase Conference Papers
Publish Date
2007

Extracting intrinsic synchronous fluorescence for spectral imaging

A ratio-metric method was proposed to extract intrinsic fluorescence from synchronous fluorescence spectra distorted by absorption and scattering. Its applicable range was investigated using Monte Carlo simulations and the accuracy was tested with phantom experiments. © 2007 Optical Society of America.

Authors
Liu, Q; Vo-Dinh, T
MLA Citation
Liu, Q, and Vo-Dinh, T. "Extracting intrinsic synchronous fluorescence for spectral imaging." Optics InfoBase Conference Papers (January 1, 2007).
Source
scopus
Published In
Optics InfoBase Conference Papers
Publish Date
2007

Extracting intrinsic synchronous fluorescence for spectral imaging

A ratio-metric method was proposed to extract intrinsic fluorescence from synchronous fluorescence spectra distorted by absorption and scattering. Its applicable range was investigated using Monte Carlo simulations and the accuracy was tested with phantom experiments. © 2007 Optical Society of America.

Authors
Liu, Q; Vo-Dinh, T
MLA Citation
Liu, Q, and Vo-Dinh, T. "Extracting intrinsic synchronous fluorescence for spectral imaging." Optics InfoBase Conference Papers (January 1, 2007).
Source
scopus
Published In
Optics InfoBase Conference Papers
Publish Date
2007

Plasmon resonances of nanoshells of spheroidal shape

Plasmon resonances are computed for nanoshells of prolate and oblate spheroidal shape. Both longitudinal and transverse resonances are investigated as a function of aspect ratio and shell thickness. Formulas for the surface charge density on the outside and inside shell surfaces are derived. © 2007 IEEE.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Plasmon resonances of nanoshells of spheroidal shape." IEEE Transactions on Nanotechnology 6.6 (2007): 627-638.
PMID
23976876
Source
scival
Published In
IEEE Transactions on Nanotechnology
Volume
6
Issue
6
Publish Date
2007
Start Page
627
End Page
638
DOI
10.1109/TNANO.2007.909074

Surface-enhanced Raman scattering detection of chemical and biological agents using a portable Raman integrated tunable sensor

This paper describes a compact and rugged Raman integrated tunable sensor coupled with surface-enhanced Raman scattering substrates for the screening of a wide variety of chemical and biological agents for homeland defense applications. The field-deployable instrument, consisting of an 830-nm diode laser for excitation and an avalanche photodiode (APD) for detection, is a fully integrated, tunable, "point-and-shoot" Raman device based on solid-state acousto-optic tunable filter (AOTF) technology. It can provide direct identification of chemical and biological samples in a few seconds under field conditions. This paper illustrates some applications of this portable device for the detection of various compounds of particular interest for homeland defense applications. These include methyl parathion (a nerve agent simulant) and dipicolinic acid (a biomarker for bacillus endospore), and other chemical warfare simulants such as dimethyl methylphosphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, and 2-chloroethyl ethylsulfide, which are simulants for sarin (GB), soman (GD), tabun (GA), and sulfur mustard (HD), respectively, and intact bacteria such as Bacillus globigii, Erwinia herbicola, and Bacillus thuringiensis, which are simulants for biological warfare agents. © 2006 Elsevier B.V. All rights reserved.

Authors
Yan, F; Vo-Dinh, T
MLA Citation
Yan, F, and Vo-Dinh, T. "Surface-enhanced Raman scattering detection of chemical and biological agents using a portable Raman integrated tunable sensor." Sensors and Actuators, B: Chemical 121.1 (2007): 61-66.
Source
scival
Published In
Sensors and Actuators B: Chemical
Volume
121
Issue
1
Publish Date
2007
Start Page
61
End Page
66
DOI
10.1016/j.snb.2006.09.032

Surface-enhanced Raman scattering for identification of organic pigments and dyes in works of art and cultural heritage material

Purpose - Identification and characterization of organic pigments and dyes used in works of art and cultural heritage material such as prints, drawings, manuscripts, paintings, and textiles can provide important information for dating, authentication, and conservation treatment of these objects and studying art history in general. Applications of surface-enhanced Raman scattering (SERS) for this purpose have recently attracted increasing attention of both academic scientists and museum researchers. This paper aims to review the latest development involving the emerging applications of SERS for the analysis of organic pigments and dyes used in works of art and cultural heritage material. Design/methodology/approach - First, the importance of organic pigments and dyes in the studies of works of art and cultural heritage material and the challenges in their identification and characterization are briefly summarized. This is followed by a discussion on sampling considerations in the context of art and archaeology. Then the fundamental principle of SERS, SERS instrumentation and different types of SERS substrates are reviewed. Finally, selected examples of SERS applications to the identification of organic pigments and dyes, including the analysis of a couple of samples of artistic and archaeological interest, are presented and discussed. Findings - The last few years have witnessed the emergence of SERS as a non-destructive or micro-destructive technique for the characterization of organic pigments and dyes found in artistic and archaeological objects. Spectroscopic and microscopic measurements using SERS have provided some novel information and answers to a wide variety of questions. However, SERS application to the field of art and archaeology is still in the fledging stage of development and requires closer collaboration between academic scientists and museum researchers. But the range of possible applications is broad. Future trends point to a strong need for the development of portable instruments for field applications. Originality/value - By compiling this review, the authors hope to direct more attention toward SERS and bring together the expertise in the scientific, museum and art community to further explore the possibilities of SERS in rapid and direct identification of pigments and dyes under field conditions. © Emerald Group Publishing Limited.

Authors
Chen, K; Leona, M; Vo-Dinh, T
MLA Citation
Chen, K, Leona, M, and Vo-Dinh, T. "Surface-enhanced Raman scattering for identification of organic pigments and dyes in works of art and cultural heritage material." Sensor Review 27.2 (2007): 109-120.
Source
scival
Published In
Sensor Review
Volume
27
Issue
2
Publish Date
2007
Start Page
109
End Page
120
DOI
10.1108/02602280710731678

Theoretical simulation and focused ion beam fabrication of gold nanostructures for Surface-Enhanced Raman Scattering (SERS)

This paper describes the fabrication of gold nanopillar and nanorod arrays and theoretical calculations of electromagnetic fields (EMFs) around ordered arrangements of these nanostructures. The EMFs of both single nanopillars and dimers of nanopillars-having nanoscale gaps between the two adjacent nanopillars forming the dimers-are simulated in this work by employing the finite-difference time-domain method. In the case of simulations for dimers of nanopillars, the nanoscale gaps between the nanopillars are varied between 5 and 20 nm, and calculations of the electromagnetic fields in the vicinity of the nanopillars and in the gaps between the nanopillars were carried out. Fabrication of gold nanopillars in a controlled manner for forming SERS substrates involves focused ion beam (FIB) milling. The nanostructures were fabricated on gold-coated silica, mica, and quartz planar substrates as well as on gold-coated tips of four mode and multimode silica optical fibers. © 2008 Humana Press Inc., 2009.

Authors
Dhawan, A; Gerhold, M; Vo-Dinh, T
MLA Citation
Dhawan, A, Gerhold, M, and Vo-Dinh, T. "Theoretical simulation and focused ion beam fabrication of gold nanostructures for Surface-Enhanced Raman Scattering (SERS)." Nanobiotechnology 3.3-4 (2007): 164-171.
PMID
23976888
Source
scival
Published In
NanoBioTechnology
Volume
3
Issue
3-4
Publish Date
2007
Start Page
164
End Page
171
DOI
10.1007/s12030-008-9017-x

Nanobiosensing using plasmonics nanoprobes

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Nanobiosensing using plasmonics nanoprobes." Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS (2007): 149-150.
Source
scival
Published In
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
Publish Date
2007
Start Page
149
End Page
150
DOI
10.1109/LEOS.2007.4382320

Tracking SERS-active nanoprobe intracellular uptake for chemical and biological sensing

A critical aspect of the use of nanoprobes for intracellular studies in chemical and biological sensing involves a fundamental understanding of their uptake and trajectory in cells. In this study, we describe experiments using surfaceenhanced Raman scattering (SERS) spectroscopy and mapping to track cellular uptake of plasmonics-active labeled nanoparticles. Three different Raman-active labels with positive, negative, and neutral charges were conjugated to silver colloidal nanoparticles with the aim of spatially and temporally profiling intracellular delivery and tracking of nanoprobes during uptake in single mammalian cells. 1-D Raman spectra and 2-D Raman mapping are used to identify and locate the probes via their SERS signal intensities. Because Raman spectroscopy is very specific for identification of chemical and molecular signatures, the development of functionalized plasmonics-active nanoprobes capable of exploring intracellular spaces and processes has the ability to provide specific information on the effects of biological and chemical pollutants in the intracellular environment. The results indicate that this technique will allow study of when, where, and how these substances affect cells and living organisms.

Authors
Gregas, MK; Yan, F; Scaffidi, J; Wang, H-N; Khoury, C; Zhang, Y; Vo-Dinh, T
MLA Citation
Gregas, MK, Yan, F, Scaffidi, J, Wang, H-N, Khoury, C, Zhang, Y, and Vo-Dinh, T. "Tracking SERS-active nanoprobe intracellular uptake for chemical and biological sensing." Proceedings of SPIE - The International Society for Optical Engineering 6755 (2007).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
6755
Publish Date
2007
DOI
10.1117/12.758287

Progress in Biomedical Optics and Imaging - Proceedings of SPIE: Introduction

Authors
Wax, A; Backman, V
MLA Citation
Wax, A, and Backman, V. "Progress in Biomedical Optics and Imaging - Proceedings of SPIE: Introduction." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 6446 (2007): ix-.
Source
scival
Published In
Proceedings of SPIE
Volume
6446
Publish Date
2007
Start Page
ix

Time-resolved optical tomography using short-pulse laser for tumor detection.

Our objective is to perform a comprehensive experimental and numerical analysis of the short-pulse laser interaction with a tissue medium with the goal of tumor-cancer diagnostics. For a short-pulse laser source, the shape of the output signal is a function of the optical properties of the medium, and hence the scattered temporal optical signal helps in understanding the medium characteristics. Initially experiments are performed on tissue phantoms embedded with inhomogeneities to optimize the time-resolved optical detection scheme. Both the temporal and the spatial profiles of the scattered reflected and transmitted optical signals are compared with the numerical modeling results obtained by solving the transient radiative transport equation using the discrete ordinates technique. Next experiments are performed on in vitro rat tissue samples to characterize the interaction of light with skin layers and to validate the time-varying optical signatures with the numerical model. The numerical modeling results and the experimental measurements are in excellent agreement for the different parameters studied. The final step is to perform in vivo imaging of anesthetized rats with tumor-promoting agents injected inside skin tissues and of an anesthetized mouse with mammary tumors to demonstrate the feasibility of the technique for detecting tumors in an animal model.

Authors
Pal, G; Basu, S; Mitra, K; Vo-Dinh, T
MLA Citation
Pal, G, Basu, S, Mitra, K, and Vo-Dinh, T. "Time-resolved optical tomography using short-pulse laser for tumor detection." Appl Opt 45.24 (August 20, 2006): 6270-6282.
PMID
16892133
Source
pubmed
Published In
Applied Optics
Volume
45
Issue
24
Publish Date
2006
Start Page
6270
End Page
6282

Hyperspectral imaging system using acousto-optic tunable filter for flow cytometry applications.

A major advantage of flow cytometry is its flexible and open instrument configuration, which is highly suitable for systems integration. This flexibility permits the coupling of auxiliary instrumentation that may offer the measurement of parameters other than those typically measured by this multiparameter measurement technique. On the basis of this advantage, we explore the principle and application of hyperspectral imaging (HSI), which has the potential to be a useful add-on feature to flow cytometry applications. Application of HSI to flow cytometry involves the acquisition of spatial information and rendering it in spectral form. In this work, we describe the development and application of an HSI system which provides both spectral and spatial information. Spectral information was generated by obtaining an entire spectrum of a single sample site within a wavelength region of interest, while spatial information was generated by recording a two-dimensional (2D) image of an area of the sample of interest at one specific wavelength. HSI is a promising additional feature to flow cytometry since it can provide both spatial (image format) and spectral information in addition to the multiparameter information already available from flow cytometry measurements.

Authors
Kasili, PM; Vo-Dinh, T
MLA Citation
Kasili, PM, and Vo-Dinh, T. "Hyperspectral imaging system using acousto-optic tunable filter for flow cytometry applications." Cytometry A 69.8 (August 1, 2006): 835-841.
PMID
16969807
Source
pubmed
Published In
Cytometry Part A
Volume
69
Issue
8
Publish Date
2006
Start Page
835
End Page
841
DOI
10.1002/cyto.a.20307

Self-assembly of silver nanoparticles: Synthesis, stabilization, optical properties, and application in surface-enhanced Raman scattering

Authors
Panigrahi, S; Praharaj, S; Basu, S; Ghosh, SK; Jana, S; Pande, S; Vo-Dinh, T; Jiang, H; Pal, T
MLA Citation
Panigrahi, S, Praharaj, S, Basu, S, Ghosh, SK, Jana, S, Pande, S, Vo-Dinh, T, Jiang, H, and Pal, T. "Self-assembly of silver nanoparticles: Synthesis, stabilization, optical properties, and application in surface-enhanced Raman scattering." JOURNAL OF PHYSICAL CHEMISTRY B 110.27 (July 13, 2006): 13436-13444.
Source
wos-lite
Published In
The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces and Biophysical
Volume
110
Issue
27
Publish Date
2006
Start Page
13436
End Page
13444
DOI
10.1021/jp0621191

Self-assembly of silver nanoparticles: synthesis, stabilization, optical properties, and application in surface-enhanced Raman scattering.

Silver nanoparticle aggregates were synthesized in large scale using resorcinol under alkaline condition to obtain an assembly of silver clusters. Stable dispersion of the cluster in aqueous medium has been examined out of resorcinol-capped silver nanoparticle assemblies. The UV-vis spectroscopy during the particle evolution has been studied in detail. From the high-resolution TEM (HRTEM) image and XRD pattern it was confirmed that the particles are made of pure silver only. The capping action of resorcinol has been authenticated from the FTIR spectra. UV-vis spectroscopy and TEM images reveal that the temperature, effect of vibrational energy, heat shock, and time-dependent particle evolution have unique bearing on the stability and surface properties of the clusters. The concentrations of silver nitrate, resorcinol, and NaOH have important influence on the particle evolution and its size. TEM images incite us to examine the aggregates to capitulate surface-enhanced Raman scattering (SERS) to the single molecular level using crystal violet (CV) and cresyl fast violet (CFV) as molecular probes. The SERS intensity of CV increases with increasing the size of the silver aggregate.

Authors
Panigrahi, S; Praharaj, S; Basu, S; Ghosh, SK; Jana, S; Pande, S; Vo-Dinh, T; Jiang, H; Pal, T
MLA Citation
Panigrahi, S, Praharaj, S, Basu, S, Ghosh, SK, Jana, S, Pande, S, Vo-Dinh, T, Jiang, H, and Pal, T. "Self-assembly of silver nanoparticles: synthesis, stabilization, optical properties, and application in surface-enhanced Raman scattering." J Phys Chem B 110.27 (July 13, 2006): 13436-13444.
PMID
16821868
Source
pubmed
Published In
The Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces and Biophysical
Volume
110
Issue
27
Publish Date
2006
Start Page
13436
End Page
13444
DOI
10.1021/jp062119l

Development of an advanced hyperspectral imaging (HSI) system with applications for cancer detection.

An advanced hyper-spectral imaging (HSI) system has been developed having obvious applications for cancer detection. This HSI system is based on state-of-the-art liquid crystal tunable filter technology coupled to an endoscope. The goal of this unique HSI technology being developed is to obtain spatially resolved images of the slight differences in luminescent properties of malignant versus non-malignant tissues. In this report, the development of the instrument is discussed and the capability of the instrument is demonstrated by observing mouse carcinomas in-vivo. It is shown that the instrument successfully distinguishes between normal and malignant mouse skin. It is hoped that the results of this study will lead to advances in the optical diagnosis of cancer in humans.

Authors
Martin, ME; Wabuyele, MB; Chen, K; Kasili, P; Panjehpour, M; Phan, M; Overholt, B; Cunningham, G; Wilson, D; Denovo, RC; Vo-Dinh, T
MLA Citation
Martin, ME, Wabuyele, MB, Chen, K, Kasili, P, Panjehpour, M, Phan, M, Overholt, B, Cunningham, G, Wilson, D, Denovo, RC, and Vo-Dinh, T. "Development of an advanced hyperspectral imaging (HSI) system with applications for cancer detection." Ann Biomed Eng 34.6 (June 2006): 1061-1068.
PMID
16783661
Source
pubmed
Published In
Annals of Biomedical Engineering
Volume
34
Issue
6
Publish Date
2006
Start Page
1061
End Page
1068
DOI
10.1007/s10439-006-9121-9

Introduction

Authors
Howarth, RB; Sinnott-Armstrong, W
MLA Citation
Howarth, RB, and Sinnott-Armstrong, W. "Introduction." Advances in the Economics of Environmental Resources 5 (April 26, 2006).
Source
scopus
Published In
Advances in the Economics of Environmental Resources
Volume
5
Publish Date
2006
DOI
10.1016/S1569-3740(05)05016-9

Nanoprobes and nanobiosensors for monitoring and imaging individual living cells.

This article presents an overview of nanobiosensors and nanoprobes. The fabrication, operating principle, and applications of these systems and their capacity for in vivo analysis and optical imaging at the single-cell level are discussed. Recently the cross-disciplinary integration of nanotechnology, biology, and photonics has been revolutionizing important areas in molecular biology, especially diagnostics and therapy at the molecular and cellular levels. Nanobiosensors and nanoprobes are a relatively new class of biosensing and imaging devices that allow for analytical measurements in individual living cells. These devices have the capacity to sense individual chemical species in specific locations within a cell. This article discusses the usefulness and potential of these nanotechnology-based systems in biological research and their applications to monitoring individual living cells.

Authors
Vo-Dinh, T; Kasili, P; Wabuyele, M
MLA Citation
Vo-Dinh, T, Kasili, P, and Wabuyele, M. "Nanoprobes and nanobiosensors for monitoring and imaging individual living cells." Nanomedicine 2.1 (March 2006): 22-30. (Review)
PMID
17292112
Source
pubmed
Published In
Nanomedicine: Nanotechnology, Biology and Medicine
Volume
2
Issue
1
Publish Date
2006
Start Page
22
End Page
30
DOI
10.1016/j.nano.2005.10.012

An AOTF-based dual-modality hyperspectral imaging system (DMHSI) capable of simultaneous fluorescence and reflectance imaging.

An acousto-optic tunable filter (AOTF)-based system for dual-modality hyperspectral imaging (DMHSI) has been developed for use in characterization of normal and malignant mouse tissue. The system consists of a laser, endoscope, AOTF, and two cameras coupled with optics and electronics. Initial results show that the system can delineate normal and malignant mouse tissues real-time. The analysis shows that malignant tissues consistently exhibit less fluorescent intensity in the wavelength band from 440 to 540 nm with a peak intensity of around 490 nm. The analysis also shows key spectroscopic differences between normal and malignant tissues. Further, these results are compared to real-time spectroscopic data and show good correlation.

Authors
Martin, ME; Wabuyele, M; Panjehpour, M; Overholt, B; DeNovo, R; Kennel, S; Cunningham, G; Vo-Dinh, T
MLA Citation
Martin, ME, Wabuyele, M, Panjehpour, M, Overholt, B, DeNovo, R, Kennel, S, Cunningham, G, and Vo-Dinh, T. "An AOTF-based dual-modality hyperspectral imaging system (DMHSI) capable of simultaneous fluorescence and reflectance imaging." Med Eng Phys 28.2 (March 2006): 149-155.
PMID
15955718
Source
pubmed
Published In
Medical Engineering & Physics
Volume
28
Issue
2
Publish Date
2006
Start Page
149
End Page
155
DOI
10.1016/j.medengphy.2005.04.022

Plasmonics and surface-enhanced raman scattering (SERS) nanoprobes for biomedical diagnostics

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Plasmonics and surface-enhanced raman scattering (SERS) nanoprobes for biomedical diagnostics." Optics InfoBase Conference Papers (January 1, 2006).
Source
scopus
Published In
Optics InfoBase Conference Papers
Publish Date
2006

Plasmonics and surface-enhanced raman scattering (SERS) nanoprobes for biomedical diagnostics

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Plasmonics and surface-enhanced raman scattering (SERS) nanoprobes for biomedical diagnostics." Optics InfoBase Conference Papers (January 1, 2006).
Source
scopus
Published In
Optics InfoBase Conference Papers
Publish Date
2006

Plasmonics and surface-enhanced Raman scattering (SERS) nanoprobes for biomedical diagnostics

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Plasmonics and surface-enhanced Raman scattering (SERS) nanoprobes for biomedical diagnostics." Optics InfoBase Conference Papers (January 1, 2006).
Source
scopus
Published In
Optics InfoBase Conference Papers
Publish Date
2006

Plasmonics and surface-enhanced Raman scattering (SERS) nanoprobes for biomedical diagnostics

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Plasmonics and surface-enhanced Raman scattering (SERS) nanoprobes for biomedical diagnostics." Optics InfoBase Conference Papers (January 1, 2006).
Source
scopus
Published In
Optics InfoBase Conference Papers
Publish Date
2006

Direct identification of alizarin and lac dye on painting fragments using surface-enhanced Raman scattering

A surface-enhanced Raman scattering (SERS) based procedure was investigated for potential applications in the direct identification of selected anthraquinone dyes on works of art objects. The simplicity and effectiveness of this procedure was demonstrated in a proof-of-concept experiment. A microscopic fragment containing alizarin or lac dye was removed from a painting. A layer of silver nanoparticles was thermally evaporated directly on the fragment to induce SERS effect. SERS spectra were collected directly from the Ag-nanoparticle-coated sample fragments with a Raman microscope. Based on their characteristic SERS spectra, the presence of alizarin or lac dye in the sample fragments can be detected. The applicability of this procedure for potential applications in minimally invasive analysis of color layer from artwork objects is discussed. Finally, the thickness of the Ag nanoparticle layer was optimized. © 2006.

Authors
Chen, K; Vo-Dinh, K-C; Yan, F; Wabuyele, MB; Vo-Dinh, T
MLA Citation
Chen, K, Vo-Dinh, K-C, Yan, F, Wabuyele, MB, and Vo-Dinh, T. "Direct identification of alizarin and lac dye on painting fragments using surface-enhanced Raman scattering." Analytica Chimica Acta 569.1-2 (2006): 234-237.
Source
scival
Published In
Analytica Chimica Acta
Volume
569
Issue
1-2
Publish Date
2006
Start Page
234
End Page
237
DOI
10.1016/j.aca.2006.03.060

Hyperspectral fluorescence imaging system for biomedical diagnostics

An advanced hyper-spectral imaging (HSI) system has been developed for use in medical diagnostics. One such diagnostic, esophageal cancer is diagnosed currently through biopsy and subsequent pathology. The end goal of this research is to develop an optical-based technique to assist or replace biopsy. In this paper, we demonstrate an instrument that has the capability to optically diagnose cancer in laboratory mice. We have developed a real-time HSI system based on state-of-the-art liquid crystal tunable filter (LCTF) technology coupled to an endoscope. This unique HSI technology is being developed to obtain spatially resolved images of the slight differences in luminescent properties of normal versus tumorous tissues. In this report, an in-vivo mouse study is shown. A predictive measure of cancer for the mice studied is developed and shown. It is hoped that the results of this study will lead to advances in the optical diagnosis of esophageal cancer in humans.

Authors
Martin, ME; Wabuyele, MB; Panjehpour, M; Phan, MN; Overholt, BF; Vo-Dinh, T
MLA Citation
Martin, ME, Wabuyele, MB, Panjehpour, M, Phan, MN, Overholt, BF, and Vo-Dinh, T. "Hyperspectral fluorescence imaging system for biomedical diagnostics." Proceedings of SPIE - The International Society for Optical Engineering 6080 (2006).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
6080
Publish Date
2006
DOI
10.1117/12.664113

Short-pulse laser propagation through tissue medium for tumor detection

The objective of this paper is to perform a comprehensive experimental and numerical analysis of the short pulse laser interaction with tissue medium with the goal of tumor / cancer diagnostics. For short pulse laser source, the shape of output signal is a function of the optical properties of the medium and hence the scattered temporal optical signal helps in understanding of the medium characteristics. Initially experiments are performed on tissue phantoms imbedded with inhomogeneities in order to optimize the time-resolved optical detection scheme. Both the temporal and the spatial profiles of the scattered reflected and transmitted optical signals are compared with the numerical modeling results obtained by solving the transient radiative transport equation using the discrete ordinates technique. Next experiments are performed on in vitro rat tissue samples to characterize the interaction of light with skin layers and to validate the time varying optical signatures with the numerical model. The numerical modeling results and the experimental measurements are in excellent agreement for the different parameters studied in this paper. The final step is to perform in vivo imaging of anaesthetized rats with tumor-promoting agents injected inside skin tissues in order to demonstrate the feasibility of the technique in detecting tumors in animal model.

Authors
Pal, G; Mitra, K; Vo-Dinh, T
MLA Citation
Pal, G, Mitra, K, and Vo-Dinh, T. "Short-pulse laser propagation through tissue medium for tumor detection." Proceedings of SPIE - The International Society for Optical Engineering 6080 (2006).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
6080
Publish Date
2006
DOI
10.1117/12.664121

FRET-based protein-DNA binding assay for detection of active NF-κB

A novel method to detect the active form of NF-κB, a transcription factor regulating a battery of inflammatory genes and playing a fundamental role in the development of numerous pathological states, has been developed. In the present work, we used fluorescence resonance energy transfer (FRET) to study DNA-protein binding interaction taking place between double-strand (ds) DNA immobilized in a glass capillary wall and p50 proteins. For this purpose, we developed a regenerable FRET-based system comprising of a single-strand (ss) DNA with auto-complementary sequence that is end-labeled with Cy5 dye and is highly specific for p50 proteins. The proteins were labeled with a Black Hole Quencher (BHQ-3) to be used as FRET pair. The interaction of p50/p50 homodimer active form with its DNA binding site was demonstrated by both electrophoretic mobility shift assays and FRET studies. These preliminary results demonstrated the feasibility of the FRET-based DNA technique to detect the active form of NF-κB protein with 90% detection efficiency. In addition, we show that the system is stable and highly regenerable. © 2005 Elsevier B.V. All rights reserved.

Authors
Giannetti, A; Citti, L; Domenici, C; Tedeschi, L; Baldini, F; Wabuyele, MB; Vo-Dinh, T
MLA Citation
Giannetti, A, Citti, L, Domenici, C, Tedeschi, L, Baldini, F, Wabuyele, MB, and Vo-Dinh, T. "FRET-based protein-DNA binding assay for detection of active NF-κB." Sensors and Actuators, B: Chemical 113.2 (2006): 649-654.
Source
scival
Published In
Sensors and Actuators B: Chemical
Volume
113
Issue
2
Publish Date
2006
Start Page
649
End Page
654
DOI
10.1016/j.snb.2005.07.014

Synthesis and characterization of SERS gene probe for BRCA-1 (breast cancer).

A protocol for binding cresyl fast violet (CFV), a SERS-active dye (label) containing an aromatic amino group with a modified oligomer having a carboxy derivatized thymidine moiety using carbodiimide coupling has been achieved for the first time. Covalent coupling between CFV and the oligomer has been confirmed by mass spectral analysis of the labeled oligomer. The fluorescence, SERS and absorption characteristics of the labeled product have been evaluated. The chosen oligomer contains a BRCA-1 (breast cancer) sequence, and hence has the potential for being used as a gene probe to identify BRCA-1 gene. It has high potential for being used in polymerase chain reaction (PCR) amplification, as has been performed with labeled oligonucleotide for the HIV sequence.

Authors
Pal, A; Isola, NR; Alarie, JP; Stokes, DL; Vo-Dinh, T
MLA Citation
Pal, A, Isola, NR, Alarie, JP, Stokes, DL, and Vo-Dinh, T. "Synthesis and characterization of SERS gene probe for BRCA-1 (breast cancer)." Faraday Discuss 132 (2006): 293-301.
PMID
16833124
Source
pubmed
Published In
Faraday Discussions
Volume
132
Publish Date
2006
Start Page
293
End Page
301

Hyperspectral fluorescence imaging for mouse skin tumor detection

This paper presents a hyperspectral imaging technique based on laser-induced fluorescence for non-invasive detection of tumorous tissue on mouse skin. Hyperspectral imaging sensors collect image data in a number of narrow, adjacent spectral bands. Such high-resolution measurement of spectral information reveals contiguous emission spectra at each image pixel useful for the characterization of constituent materials. The hyperspectral image data used in this study are fluorescence images of mouse skin consisting of 21 spectral bands in the visible spectrum of the wavelengths ranging from 440 nm to 640 nm. Fluorescence signal is measured with the use of laser excitation at 337 nm. An acousto-optic tunable filter (AOTF) is used to capture images at 10 nm intervals. All spectral band images are spatially registered with the reference band image at 490 nm to obtain exact pixel correspondences by compensating the spatial offsets caused by the refraction differences in AOTF at different wavelengths during the image capture procedure. The unique fluorescence spectral signatures demonstrate a good separation to differentiate malignant tumors from normal tissues for rapid detection of skin cancers without biopsy.

Authors
Kong, SG; Martin, ME; Vo-Dinh, T
MLA Citation
Kong, SG, Martin, ME, and Vo-Dinh, T. "Hyperspectral fluorescence imaging for mouse skin tumor detection." ETRI Journal 28.6 (2006): 770-776.
Source
scival
Published In
ETRI Journal
Volume
28
Issue
6
Publish Date
2006
Start Page
770
End Page
776

Neutron spectrometry using CR-39 track etch detectors

Track-size distributions were measured for chemically etched CR-39 foils exposed to monoenergetic neutrons with energies ranging from 0.144 to 19 MeV and to various broad-spectrum neutron sources including spontaneous fission neutrons from 238Pu. These tracks are due to energetic charged particles resulting from interactions of the neutrons with the CR-39. The tracks are visible with an optical microscope after chemical etching and vary in size and configuration depending on the particle, energy and angle of incidence. The foils were analysed using an automatic analysis system that scans the foils, identifies valid tracks and records the track-size parameters. The track-size distributions vary with neutron energy for the monoenergetic sources and with the hardness of the broad-spectrum sources. The distribution from the 238Pu fission source is readily distinguishable from the other sources measured and from distributions owing to the background. © 2006 Oxford University Press.

Authors
Phillips, GW; Spann, JE; Bogard, JS; VoDinh, T; Emfietzoglou, D; Devine, RT; Moscovitch, M
MLA Citation
Phillips, GW, Spann, JE, Bogard, JS, VoDinh, T, Emfietzoglou, D, Devine, RT, and Moscovitch, M. "Neutron spectrometry using CR-39 track etch detectors." Radiation Protection Dosimetry 120.1-4 (2006): 457-460.
PMID
16735559
Source
scival
Published In
Radiation Protection Dosimetry
Volume
120
Issue
1-4
Publish Date
2006
Start Page
457
End Page
460
DOI
10.1093/rpd/nci675

Surface-enhanced Raman scattering for biomedical diagnostics and molecular imaging

Authors
Vo-Dinh, T; Yan, F; Wabuyele, MB
MLA Citation
Vo-Dinh, T, Yan, F, and Wabuyele, MB. "Surface-enhanced Raman scattering for biomedical diagnostics and molecular imaging." Topics in Applied Physics 103 (2006): 409-426.
Source
scival
Published In
Topics in Applied Physics
Volume
103
Publish Date
2006
Start Page
409
End Page
426
DOI
10.1007/11663898_22

Application of surface-enhanced Raman scattering (SERS) for the identification of anthraquinone dyes used in works of art

Surface-enhanced Raman scattering (SERS) was investigated for applications in the analysis of anthraquinone dyes used in works of art. Two SERS procedures were developed and evaluated with three frequently used anthraquinone dyes, alizarin, carminic acid and lac dye. The first procedure involves coating a layer of silver nanoparticles directly on pieces of filter paper stained with the dyes of interest by thermal evaporation to induce SERS effect. In the second procedure, a SERS-active Ag-Al2O3 substrate was prepared by spin-coating an alumina-nanoparticle layer onto a glass slide to provide the nanostructure of the substrate, followed by thermally evaporating a layer of silver nanoparticles on top of the alumina layer. Aliquots of dye solutions were delivered onto this substrate to be analyzed. Intense SERS spectra characteristic of alizarin, carminic acid and lac dye were obtained using both SERS procedures. The effects of two parameters, the concentration of the alumina suspension and the thickness of the silver nanoparticle layer on the performance of the Ag-Al2O3 substrate were examined with alizarin as the model compound. Comparative studies were conducted between the Ag-Al2O3 substrate and the SERS substrate prepared using Tollens reaction. The Ag-Al2O3 substrate was shown to offer larger enhancement and improved reproducibility than the Tollens substrates. Finally, the potential applicability of the Ag-Al2O 3 substrate for the analysis of real artifact objects was illustrated by the identification of alizarin extracted from a small piece of textile dyed using traditional methods and materials. The limit of detection for alizarin was estimated to be 7 × 10-15 g from tests performed on solutions of known concentration. Copyright © 2005 John Wiley & Sons, Ltd.

Authors
Chen, K; Leona, M; Vo-Dinh, K-C; Yan, F; Wabuyele, MB; Vo-Dinh, T
MLA Citation
Chen, K, Leona, M, Vo-Dinh, K-C, Yan, F, Wabuyele, MB, and Vo-Dinh, T. "Application of surface-enhanced Raman scattering (SERS) for the identification of anthraquinone dyes used in works of art." Journal of Raman Spectroscopy 37.4 (2006): 520-527.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
37
Issue
4
Publish Date
2006
Start Page
520
End Page
527
DOI
10.1002/jrs.1426

Antibody-based SERS diagnostics of Fhit protein without label

Surface-enhanced Raman scattering (SERS) is a particularly promising technique that has the potential to perform highly selective and sensitive in situ measurements of antibody-antigen reactions. This work describes the use of silver (Ag) colloids for immunoassay-based SERS detection of the fragile histidine triad (Fhit) protein. Alterations in Fhit protein expression have been associated with several human cancers, and, thus, the detection of Fhit protein is important because it can potentially be used as a cancer diagnostic biomarker, for both cancer detection and therapy. Copyright © 2006 Humana Press Inc. All rights of any nature whatsoever are reserved.

Authors
Kasili, PM; Wabuyele, MB; Vo-Dinh, T
MLA Citation
Kasili, PM, Wabuyele, MB, and Vo-Dinh, T. "Antibody-based SERS diagnostics of Fhit protein without label." Nanobiotechnology 2.1-2 (2006): 29-35.
Source
scival
Published In
NanoBioTechnology
Volume
2
Issue
1-2
Publish Date
2006
Start Page
29
End Page
35
DOI
10.1007/s12030-006-0004-9

Proceedings of SPIE - The International Society for Optical Engineering: Introduction

Authors
Sedlacek, AJ; Christesen, SD; Combs, RJ; Vo-Dinh, T
MLA Citation
Sedlacek, AJ, Christesen, SD, Combs, RJ, and Vo-Dinh, T. "Proceedings of SPIE - The International Society for Optical Engineering: Introduction." December 1, 2005.
Source
scopus
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5994
Publish Date
2005

Detection of human immunodeficiency virus type 1 DNA sequence using plasmonics nanoprobes.

This paper describes the use of plasmonics-based nanoprobes that act as molecular sentinels for DNA diagnostics. The plasmonics nanoprobe comprises a metal nanoparticle and a stem-loop DNA molecule tagged with a Raman label. The nanoprobe utilizes the specificity and selectivity of the DNA hairpin probe sequence to detect a specific target DNA sequence of interest. In the absence of target DNA, the stem-loop configuration maintains the Raman label in proximity to the metal nanoparticle, inducing an intense surface-enhanced Raman scattering (SERS) effect that produces a strong Raman signal upon laser excitation. Upon hybridization of a complementary target DNA sequence to the nanoprobe, the stem-loop configuration is disrupted, causing the Raman label to physically separate from the metal nanoparticle, thus quenching the SERS signal. The usefulness and potential application of the plasmonics nanoprobe for diagnosis is demonstrated using the gag gene sequence of the human immunodeficiency virus type 1 (HIV-1). We successfully demonstrated the specificity and selectivity of the plasmonics nanoprobes to detect PCR amplicons of the HIV gene. The potential for combining the spectral selectivity and high sensitivity of the SERS process with inherent molecular specificity of DNA hairpins to diagnose molecular target sequences in homogeneous solutions is discussed.

Authors
Wabuyele, MB; Vo-Dinh, T
MLA Citation
Wabuyele, MB, and Vo-Dinh, T. "Detection of human immunodeficiency virus type 1 DNA sequence using plasmonics nanoprobes." Anal Chem 77.23 (December 1, 2005): 7810-7815.
PMID
16316192
Source
pubmed
Published In
Analytical Chemistry
Volume
77
Issue
23
Publish Date
2005
Start Page
7810
End Page
7815
DOI
10.1021/ac0514671

Optical nanobiosensor for monitoring an apoptotic signaling process in a single living cell following photodynamic therapy.

Optical nanobiosensors have enabled bioanalytical measurements to be undertaken within volumes as small as that of single biological cells. In this work, we use nanobiosensors to monitor a molecular signaling process, i.e., caspase-7 activation, following photodynamic therapy (PDT) induced apoptosis in breast cancer cells (MCF-7). PDT induces the mitochondrial pathway of apoptosis which triggers cytochrome c release, activation of caspases-9, -8 and -7 and cleavage of poly (ADP-ribose) polymerase (Parp) protein. Caspase-7 is an important apoptosis-related cysteine protease involved in the activation cascade of caspases and in the proteolytic cleavage of Parp protein. Caspase-7 was detected and identified intracellularly using optical nanobiosensors. Our results show the detection of caspase-7 in single living MCF-cells which in essence typifies the apoptotic event induced by a PDT drug. This work, in principle, demonstrates the minimally invasive capability of optical nanobiosensors to measure important signaling molecules and events in pathways at the single cell level.

Authors
Kasili, PM; Vo-Dinh, T
MLA Citation
Kasili, PM, and Vo-Dinh, T. "Optical nanobiosensor for monitoring an apoptotic signaling process in a single living cell following photodynamic therapy." J Nanosci Nanotechnol 5.12 (December 2005): 2057-2062.
PMID
16430140
Source
pubmed
Published In
Journal of nanoscience and nanotechnology
Volume
5
Issue
12
Publish Date
2005
Start Page
2057
End Page
2062

Near-real-time determination of hydrogen peroxide generated from cigarette smoke.

The ability to monitor hydrogen peroxide (H2O2) in aqueous smoke extracts will advance our understanding of the relationship between cigarette smoke-induced oxidative stress, inflammation, and disease and help elucidate the pathways by which the various smoke constituents exert their pathogenic effects. We have demonstrated, for the first time, the measurement of H2O2 production from cigarette smoke without prior separation of the sample. Cigarettes were tested on a commercial smoking machine, such that the whole smoke or gas vapor phase was bubbled through phosphate buffered saline solution at pH 7.4. Aliquots of these solutions were analyzed using an Amplex Red/horseradish peroxidase fluorimetric assay that required only a 2 minute incubation time, facilitating the rapid, facile collection of data. Catalase was used to demonstrate the selectivity and specificity of the assay for H2O2 in the complex smoke matrix. We measured approximately 7-8 microM H2O2 from two reference cigarettes (i.e., 1R4F and 2R4F). We also observed 9x more H2O2 from whole smoke bubbled samples compared to the gas vapor phase, indicating that the major constituent(s) responsible for H2O2 formation reside in the particulate phase of cigarette smoke. Aqueous solutions of hydroquinone and catechol, both of which are particulate phase constituents of cigarette smoke, generated no H2O2 even though they are free radical precursors involved in the production of reactive oxygen species in the smoke matrix.

Authors
Yan, F; Williams, S; Griffin, GD; Jagannathan, R; Plunkett, SE; Shafer, KH; Vo-Dinh, T
MLA Citation
Yan, F, Williams, S, Griffin, GD, Jagannathan, R, Plunkett, SE, Shafer, KH, and Vo-Dinh, T. "Near-real-time determination of hydrogen peroxide generated from cigarette smoke." J Environ Monit 7.7 (July 2005): 681-687.
PMID
15986047
Source
pubmed
Published In
Journal of Environmental Monitoring
Volume
7
Issue
7
Publish Date
2005
Start Page
681
End Page
687
DOI
10.1039/b502061a

Fiber-optic nanosensors for single-cell monitoring.

This article is an overview of the fabrication, operating principles, and applications of fiber-optic nanobiosensors with the capability of in-vivo analysis at the single-cell level. Recently, the cross-disciplinary integration of nanotechnology, biology, and photonics has been revolutionizing important areas in molecular biology, especially diagnostics and therapy at the molecular and cellular level. Fiber-optic nanobiosensors are a unique class of biosensor that enable analytical measurements in individual living cells and the probing of individual chemical species in specific locations within a cell. This article provides a review of the research performed in our laboratory and discusses the usefulness and potential of this nanotechnology-based biosensor system in biological research and its applications to biomonitoring of individual cells.

Authors
Vo-Dinh, T; Kasili, P
MLA Citation
Vo-Dinh, T, and Kasili, P. "Fiber-optic nanosensors for single-cell monitoring." Anal Bioanal Chem 382.4 (June 2005): 918-925. (Review)
PMID
15928944
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
382
Issue
4
Publish Date
2005
Start Page
918
End Page
925
DOI
10.1007/s00216-005-3256-7

A compact CMOS biochip immunosensor towards the detection of a single bacteria.

Recent use of biological warfare (BW) agents has led to a growing interest in the rapid and sensitive detection of pathogens. Therefore, the development of field-usable detection devices for sensitive and selective detection of BW agents is an important issue. In this work, we report a portable biochip system based on complementary metal oxide semiconductor (CMOS) technology that has great potential as a device for single-bacteria detection. The possibility of single-bacteria detection is reported using an immunoassay coupled to laser-induced fluorescence (LIF) detection. Bacillus globigii spores, which are a surrogate species for B. anthracis spores, were used as the test sample. Enzymatic amplification following immunocomplex formation allowed remarkably sensitive detection of B. globigii spores, and could preclude a complicated optical and instrumental system usually required for high-sensitive detection. Atomic force microscopy (AFM) was employed to investigate whether B. globigii spores detected in the portable biochip system exist in single-cell or multicellular form. It was found that B. globigii spores mostly exist in multicellular form with a small minority of single-cell form. The results showed that the portable biochip system has great potential as a device for single-particle or possibly even single-organism detection.

Authors
Song, JM; Culha, M; Kasili, PM; Griffin, GD; Vo-Dinh, T
MLA Citation
Song, JM, Culha, M, Kasili, PM, Griffin, GD, and Vo-Dinh, T. "A compact CMOS biochip immunosensor towards the detection of a single bacteria." Biosens Bioelectron 20.11 (May 15, 2005): 2203-2209.
PMID
15797317
Source
pubmed
Published In
Biosensors and Bioelectronics
Volume
20
Issue
11
Publish Date
2005
Start Page
2203
End Page
2209
DOI
10.1016/j.bios.2004.08.033

FRET based biosensor for detection of active NF-kB

The Nuclear Factor kB is a transcription factor, ubiquitously expressed, involved in the regulation of a large number of genes and in a variety of human disease including inflammation, asthma, atherosclerosis, AIDS, septic shock, arthritis and cancer. The critical need for a simple and direct method to evaluate the quantity of active NF-kB in a biological sample can be addressed using a suitable and reusable biosensor. For this purpose, a novel method, using fluorescence resonance energy transfer (FRET), to detect the active form of NF-kB binding a specific DNA sequence has been developed. A single-stranded DNA (ssDNA) with auto-complementary sequence has been properly designed and synthesized. In order to evaluate FRET due to the DNA/protein binding interaction taking place between double-stranded DNA (dsDNA) immobilized in a capillary wall and NF-kB proteins, a highly sensitive FRET-based biosensor system developed in our laboratory was used. Preliminary results show that our system was capable of detecting the active form of NF-kB protein with a detection efficiency of about 90% and that the system has a good regenerability.

Authors
Baldini, F; Citti, L; Domenici, C; Giannetti, A; Tedeschi, L; Vo-Dinh, T; Wabuyele, MB
MLA Citation
Baldini, F, Citti, L, Domenici, C, Giannetti, A, Tedeschi, L, Vo-Dinh, T, and Wabuyele, MB. "FRET based biosensor for detection of active NF-kB." Proceedings of SPIE - The International Society for Optical Engineering 5855 PART I (2005): 439-442.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5855 PART I
Publish Date
2005
Start Page
439
End Page
442
DOI
10.1117/12.623696

Portable Raman device for detection of chemical and biological warfare agents

This paper describes a compact, self-contained, cost effective, and portable Raman Integrated Tunable Sensor (RAMiTs) for screening a wide variety of chemical and biological agents for homeland defense applications. The instrument is a fully-integrated, tunable, "point-and-shoot" Raman monitor based on solid-state acousto-optic tunable filter (AOTF) technology. It can provide direct identification and quantitative analysis of chemical and biological samples in a few seconds under field conditions. It also consists of a 830-nm diode laser for excitation, and an avalanche photodiode for detection. Evaluation of this instrument has been performed by analyzing several standard samples and comparing the results those obtained using a conventional Raman system. In addition to system evaluation, this paper will also discuss potential applications of the RAMiTs for detection of chemical and biological warfare agents.

Authors
Wabuyele, MB; Martin, ME; Yan, F; Stokes, DL; Mobley, J; Cullum, BM; Wintenberg, A; Lenarduzzi, R; Vo-Dinh, T
MLA Citation
Wabuyele, MB, Martin, ME, Yan, F, Stokes, DL, Mobley, J, Cullum, BM, Wintenberg, A, Lenarduzzi, R, and Vo-Dinh, T. "Portable Raman device for detection of chemical and biological warfare agents." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5692 (2005): 330-336.
Source
scival
Published In
Proceedings of SPIE
Volume
5692
Publish Date
2005
Start Page
330
End Page
336
DOI
10.1117/12.604451

A sol-gel derived AgCl photochromic coating on glass for SERS chemical sensor application

A new optically translucent material has been prepared that acts as a substrate for surface-enhanced Raman spectroscopy. This material is a silica matrix, synthesized by the sol-gel method and containing in situ precipitated AgCl particles which serve as precursors for nanoparticles of elemental silver. Reduction of AgCl to silver nanoparticles is achieved by UV irradiation. The SERS-active medium was distributed on glass supports (cover glass slips, 0.5 mm thick), hence producing thin, sturdy, and optically translucent substrates. SERS activity was evaluated by using brilliant cresyl blue and 1-aminopyrene as model compounds. Parameters including the sol-gel composition, the aging period of the sol-gel, and the UV exposure time for photoreduction of the SERS medium were thoroughly investigated. These new substrates have exhibited long shelf lives; furthermore, they can be easily regenerated through a redox cycle involving chemical oxidation and photoreduction steps. In addition to use in direct chemical analysis, this novel type of SERS substrate can be used for indirect monitoring of HNO3 acid vapor via measurement of the SERS signal of 1-aminoyrene, which is attenuated as the substrate is oxidized by the acid vapor. © 2004 Elsevier B.V. All rights reserved.

Authors
Volkan, M; Stokes, DL; Vo-Dinh, T
MLA Citation
Volkan, M, Stokes, DL, and Vo-Dinh, T. "A sol-gel derived AgCl photochromic coating on glass for SERS chemical sensor application." Sensors and Actuators, B: Chemical 106.2 (2005): 660-667.
Source
scival
Published In
Sensors and Actuators, B: Chemical
Volume
106
Issue
2
Publish Date
2005
Start Page
660
End Page
667
DOI
10.1016/j.snb.2004.09.019

Hyperspectral fluorescence image analysis for use in medical diagnostics

This paper presents hyperspectral fluorescence imaging and a support vector machine for detecting skin tumors. Skin cancers may not be visually obvious since the visual signature appears as shape distortion rather than discoloration. As a definitive test for cancer diagnosis, skin biopsy requires both trained professionals and significant waiting time. Hyperspectral fluorescence imaging offers an instant, non-invasive diagnostic procedure based on the analysis of the spectral signatures of skin tissue. A hyperspectral image contains spatial information measured at a sequence of individual wavelength across a sufficiently broad spectral band at high-resolution spectrum. Fluorescence is a phenomenon where light is absorbed at a given wavelength and then is normally followed by the emission of light at a longer wavelength. Fluorescence generated by the skin tissue is collected and analyzed to determine whether cancer exists. Oak Ridge National Laboratory developed an endoscopic hyperspectral imaging system capable of fluorescence imaging for skin cancer detection. This hyperspectral imaging system captures hyperspectral images of 21 spectral bands of wavelength ranging from 440 nm to 640 nm. Each band image is spatially co-registered to eliminate the spectral offset caused during the image capture procedure. Image smoothing by means of a local spatial filter with Gaussian kernel increases the classification accuracy and reduces false positives. Experiments show that the SVM classification with spatial filtering achieves high skin tumor detection accuracies.

Authors
Kong, SG; Du, Z; Martin, M; Vo-Dinh, T
MLA Citation
Kong, SG, Du, Z, Martin, M, and Vo-Dinh, T. "Hyperspectral fluorescence image analysis for use in medical diagnostics." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5692 (2005): 21-28.
Source
scival
Published In
Proceedings of SPIE
Volume
5692
Publish Date
2005
Start Page
21
End Page
28
DOI
10.1117/12.596463

Progress in Biomedical Optics and Imaging - Proceeding of SPIE: Introduction

Authors
Tuchin, VV; Izatt, JA; Fujimoto, JG
MLA Citation
Tuchin, VV, Izatt, JA, and Fujimoto, JG. "Progress in Biomedical Optics and Imaging - Proceeding of SPIE: Introduction." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5690 (2005): xv-xvi.
Source
scival
Published In
Proceedings of SPIE
Volume
5690
Publish Date
2005
Start Page
xv
End Page
xvi

Surface-enhanced Raman scattering for medical diagnostics and biological imaging

We present recent development and applications of a surface-enhanced Raman scattering (SERS) technology for use in medical diagnostics and biological imaging. For medical diagnostics, we use Raman-active dye-labeled DNA gene probes and nanostructured metallic substrates as SERS-active platforms. The surface-enhanced Raman gene probes can be used to detect DNA biotargets (e.g. gene sequences, bacteria and viral DNA) via hybridization to DNA sequences complementary to these probes. The SERS gene probes eliminate the need for radioactive labels and have great potential to provide both sensitivity, selectivity and label multiplexing for DNA sequencing and clinical assays. We also describe a hyperspectral surface-enhanced Raman imaging (HSERI) system that combines imaging capabilities with SERS detection to identify cellular components with high spatial and temporal resolution. The HSERI system's application to biological imaging is demonstrated using Raman dye-labeled silver nanoparticles in cellular systems. Copyright © 2005 John Wiley & Sons, Ltd.

Authors
Vo-Dinh, T; Yan, F; Wabuyele, MB
MLA Citation
Vo-Dinh, T, Yan, F, and Wabuyele, MB. "Surface-enhanced Raman scattering for medical diagnostics and biological imaging." Journal of Raman Spectroscopy 36.6-7 (2005): 640-647.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
36
Issue
6-7
Publish Date
2005
Start Page
640
End Page
647
DOI
10.1002/jrs.1348

Surface-enhanced Raman scattering detection of chemical and biological agent simulants

Surface-enhanced Raman scattering spectra of chemical and biological agent simulants, such as dimethyl methylphonate, pinacolyl methylphosphonate, diethyl phosphoramidate, 2-chloroethyl ethylsulfide, bacillus globigii, erwinia herbicola, and bacillus thuringiensis were obtained from silver-oxide film-deposited substrates. Thin AgO films ranging in thickness from 50 to 250 nm were produced by chemical bath deposition onto glass slides. Further Raman intensity enhancements were noticed in UV irradiated surfaces due to photo-induced Ag nanocluster formation, which may provide a possible route to producing highly useful plasmonic sensors for the detection of chemical and biological agents upon visible-light illumination.

Authors
Yan, F; Wabuyele, MB; Griffin, GD; Vass, AA; Vo-Dinh, T
MLA Citation
Yan, F, Wabuyele, MB, Griffin, GD, Vass, AA, and Vo-Dinh, T. "Surface-enhanced Raman scattering detection of chemical and biological agent simulants." IEEE Sensors Journal 5.4 (2005): 665-670.
Source
scival
Published In
IEEE Sensors Journal
Volume
5
Issue
4
Publish Date
2005
Start Page
665
End Page
670
DOI
10.1109/JSEN.2005.850993

Liposome encapsulated gold nanoshells for NanoPhototherapy induced hyperthermia

Gold nanoshells have been extensively studied since their invention and their role in both in vitro and in vivo photothermal therapy has been explored and demonstrated. In this work, we investigate liposomal delivery of gold nanoshells and evaluate their effects for in vitro NanoPhototherapy induced hyperthermia in human mammary carcinoma cells. In addition, we compare the application of liposome encapsulated gold nanoshells and free standing gold nanoshells in NanoPhototherapy. NanoPhotoTherapy induced hyperthermia was performed using a 785 nm near-infrared light from a diode laser and the in vitro effects were evaluated using nucleic acid molecular probes by fluorescence microscopy. Additionally, we monitored apoptosis by detecting capase-9 activity. Copyright © 2005 Inderscience Enterprises Ltd.

Authors
Kasili, PM; Vo-Dinh, T
MLA Citation
Kasili, PM, and Vo-Dinh, T. "Liposome encapsulated gold nanoshells for NanoPhototherapy induced hyperthermia." International Journal of Nanotechnology 2.4 (2005): 397-410.
Source
scival
Published In
International Journal of Nanotechnology
Volume
2
Issue
4
Publish Date
2005
Start Page
397
End Page
410

Instrumentation considerations in spectral imaging for tissue demarcation: Comparing three methods of spectral resolution

Multiple methodologies exist to implement spectral imaging for tissue demarcation and disease diagnosis. In this paper, benchtop acousto-optic tunable filter (AOTF), liquid-crystal tunable filter (LCTF) and Fourier interferometric spectral imaging systems were quantitatively compared in terms of imaging speed of soft tissue autofluorescence. Optical throughput, image signal-to-noise ratio (SNR), and collagen autofluorescence imaging in chicken breast were assessed. Within this comparison, the Fourier system possessed the largest optical throughput (∼50%) relative to the tunable-filter imaging systems; however, its throughput advantage failed to correlate to improved image SNR over the LCTF system. Further, while the autofluorescence imaging capability of the Fourier system exceeded that of the LCTF system for comparable total image integration times, the LCTF is capable of producing equivalent autofluorescence SNR with superior SNR when interrogations at only a few wavelengths are required and the random access filter tuning of the LCTF can be exploited. Therefore, the simple, rugged design and random-access filter-tuning capability of LCTF-based spectral imaging makes it best-suited for clinical development of soft tissue autofluorescence imaging.

Authors
Gebhart, SC; Stokes, DL; Vo-Dinh, T; Mahadevan-Jansen, A
MLA Citation
Gebhart, SC, Stokes, DL, Vo-Dinh, T, and Mahadevan-Jansen, A. "Instrumentation considerations in spectral imaging for tissue demarcation: Comparing three methods of spectral resolution." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5694 (2005): 41-52.
Source
scival
Published In
Proceedings of SPIE
Volume
5694
Publish Date
2005
Start Page
41
End Page
52
DOI
10.1117/12.611351

A comparison of enhancement factors for surface-enhanced Raman scattering using visible and near-infrared excitations

We investigated enhancement factors for surface-enhanced Raman scattering from p-aminobenzoic acid (PABA) on different silver and gold substrates using visible (632.8 nm) and near-infrared (NIR) (1064 nm) excitations. The results indicated that the use of NIR excitation provided larger enhancements (about 10-100 times) than those obtained using the visible excitation. The enhancement factors for the PABA on the silver coated alumina, silver island, gold-coated alumina, and gold island are 2.7×106, 4.3×105, 3.0×104, and 6.0×103, respectively, with the NIR excitation, and are 4.6×104, 4.7×103, 1.2×103, and 6.0×102, respectively, with the visible excitation. © 2004 Elsevier B.V. All rights reserved.

Authors
Ibrahim, A; Oldham, PB; Stokes, DL; Vo-Dinh, T; Loo, BH
MLA Citation
Ibrahim, A, Oldham, PB, Stokes, DL, Vo-Dinh, T, and Loo, BH. "A comparison of enhancement factors for surface-enhanced Raman scattering using visible and near-infrared excitations." Journal of Molecular Structure 735-736.SPEC. ISS. (2005): 69-73.
Source
scival
Published In
Journal of Molecular Structure
Volume
735-736
Issue
SPEC. ISS.
Publish Date
2005
Start Page
69
End Page
73
DOI
10.1016/j.molstruc.2004.09.033

Surface-enhanced Raman scattering molecular nanoprobes

Nanoparticles are increasingly finding a wide application in the biological studies due to their unique physical and chemical properties. Colloidal nanoparticles are efficient substrate that exhibit surface-enhanced Raman scattering (SERS) phenomenon by enhancing the scattering cross-sections of conjugated Raman active molecules thus enabling highly sensitive biological probes. However, biological and medical applications would require nanoparticles to be conjugated to biomolecules. A universal approach for conjugation of mercarptoacetic acid-capped silver nanoparticles to biomolecules is described. The surface functionalized silver colloids were labeled with a Raman active dye and used for cellular imaging. We also described the use of silver nanoparticle to develop a new class of SERS nanoprobes for molecular recognition and detection of specific nucleic acid sequences.

Authors
Wabuyele, MB; Yan, F; Griffin, GD; Vo-Dinh, T
MLA Citation
Wabuyele, MB, Yan, F, Griffin, GD, and Vo-Dinh, T. "Surface-enhanced Raman scattering molecular nanoprobes." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5692 (2005): 209-215.
Source
scival
Published In
Proceedings of SPIE
Volume
5692
Publish Date
2005
Start Page
209
End Page
215
DOI
10.1117/12.604447

Application of surface-enhanced Raman scattering (SERS) for the identification of anthraquinone dyes used in works of art

Surface-enhanced Raman scattering (SERS) was investigated for applications in the analysis of anthraquinone dyes used in works of art. Two SERS procedures were developed and evaluated with frequently used anthraquinone dyes, alizarin, carminic acid and lac dye. The first procedure involves the removal of a microscopic fragment containing alizarin from a painting, and a layer of silver nanoparticles was thermally evaporated directly on the fragment to induce SERS signal from alizarin. The applicability of this procedure for analyzing solid samples of color layer from paintings was discussed in detail. In the second procedure, a SERS-active substrate was prepared by spin-coating an alumina-nanoparticle layer onto a glass slide, followed by thermally evaporating a layer of silver nanoparticles on top of the alumina layer. Aliquots of dye solutions were delivered onto this substrate where intense SERS spectra characteristic of alizarin, carminic acid, and lac dye were obtained. The effects of two parameters, the concentration of the alumina suspension, and the thickness of the silver nanoparticle layer, on the performance of the Ag-Al 2O 3 substrate were examined with alizarin as the model compound. Comparative studies with other common SERS substrates showed larger enhancement and improved reproducibility for the Ag-Al 2C 3 substrate. The potential applicability of the Ag-Al 2O 3 substrate for the analysis of real artifact objects was illustrated by the identification of alizarin extracted from a small piece of textile dyed with traditional methods and materials. The limit of detection for alizarin was estimated to be 7×10 -15 g from tests using solutions of known concentration.

Authors
Chen, K; Leona, M; Vo-Dinh, KC; Yan, F; Wabuyele, M; Vo-Dinh, T
MLA Citation
Chen, K, Leona, M, Vo-Dinh, KC, Yan, F, Wabuyele, M, and Vo-Dinh, T. "Application of surface-enhanced Raman scattering (SERS) for the identification of anthraquinone dyes used in works of art." Proceedings of SPIE - The International Society for Optical Engineering 5993 (2005).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5993
Publish Date
2005
DOI
10.1117/12.639103

Dual modality fluorescence and reflectance Hyperspectral imaging: Principle and applications

We present the principles and applications of our dual-modality fluorescence and reflectance hyperspectral imaging (DMHSI) system. In this paper we report on background work done using laser induced fluorescence (LIF) by the group in the early detection of esophageal cancer. We then demonstrate the capabilities of our new DMHSI system. The system consists of a laser, endoscope, AOTF, and two cameras coupled with optics and electronics. Preliminary results, performed on mouse tissue, show that the system can delineate normal and malignant tissue regions in real-time.

Authors
Martin, ME; Wabuyele, MB; Panjehpour, M; Phan, MN; Overholt, BF; DeNovo, RC; Moyers, T; Song, SG; Vo-Dinh, T
MLA Citation
Martin, ME, Wabuyele, MB, Panjehpour, M, Phan, MN, Overholt, BF, DeNovo, RC, Moyers, T, Song, SG, and Vo-Dinh, T. "Dual modality fluorescence and reflectance Hyperspectral imaging: Principle and applications." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5692 (2005): 133-139.
Source
scival
Published In
Proceedings of SPIE
Volume
5692
Publish Date
2005
Start Page
133
End Page
139
DOI
10.1117/12.604445

Hyperspectral surface-enhanced Raman imaging of labeled silver nanoparticles in single cells

We describe the development of an acousto-optic tunable filter (AOTF) -based hyperspectral surface-enhanced Raman imaging (HSERI) system equipped with an intensified charged coupled device and an avalanche photodiode. The AOTF device is a miniature rapid-scanning solid-state device that has no moving parts and can be rapidly tuned (microseconds) either sequentially or randomly, over a wide spectral range between 600 and 900 nm [corresponding to a large relative wave number range (~0-4500 cm-1)], with respect to a 632.8 nm excitation and can also acquire images at a fairly narrow band of ~7 cm-1. In this article we describe a confocal surface-enhanced Raman imaging (SERI) system developed in our laboratory that combines hyperspectral imaging capabilities with surface-enhanced Raman scattering (SERS) to identify cellular components with high spatial and temporal resolution. The HSERI system's application to cellular imaging is demonstrated using SERS-labeled nanoparticles in cellular systems. © 2005 American Institute of Physics.

Authors
Wabuyele, MB; Yan, F; Griffin, GD; Vo-Dinh, T
MLA Citation
Wabuyele, MB, Yan, F, Griffin, GD, and Vo-Dinh, T. "Hyperspectral surface-enhanced Raman imaging of labeled silver nanoparticles in single cells." Review of Scientific Instruments 76.6 (2005).
Source
scival
Published In
Review of Scientific Instruments
Volume
76
Issue
6
Publish Date
2005
DOI
10.1063/1.1938667

Portable AOTF Raman Integrated Tunable Sensor (RAMiTS) for chemical and biosensing

This paper describes the development of a compact, self-contained, and portable Raman Integrated Tunable Sensor (RAMiTS) for chemical and biosensing. The RAMiTS consists of a frequency-stabilized diode laser for excitation, an acousto-optic tunable filter (AOTF) for wavelength discrimination, and an avalanche photodiode (APD) for detection. It can provide direct identification and quantitative analysis of chemical and biological samples in a few seconds under field conditions. Instrument control and data acquisition was coordinated by software developed in house using the C language. Evaluation of this instrument was performed by analyzing several model compounds and the high spectral resolution of this instrument was demonstrated by the discrimination of several structurally similar molecules (benzene, toluene and naphthalene) as well as m-, o-, p- isomers of xylene. The potential applications of the RAMiTS coupled with the surface-enhanced Raman scattering (SERS) for the detection of chemical and biological warfare agents will also be discussed in this paper.

Authors
Chen, K; Martin, ME; Vo-Dinh, T
MLA Citation
Chen, K, Martin, ME, and Vo-Dinh, T. "Portable AOTF Raman Integrated Tunable Sensor (RAMiTS) for chemical and biosensing." Proceedings of SPIE - The International Society for Optical Engineering 5993 (2005).
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5993
Publish Date
2005
DOI
10.1117/12.639098

The new paradigm shift at the convergence of nanotechnology, molecular biology, and biomedical sciences

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "The new paradigm shift at the convergence of nanotechnology, molecular biology, and biomedical sciences." Nanobiotechnology 1.1 (2005): 3-6.
Source
scival
Published In
Nanobiotechnology
Volume
1
Issue
1
Publish Date
2005
Start Page
3
End Page
6
DOI
10.1385/Nano:1:1:3

Progress in Biomedical Optics and Imaging - Proceedings of SPIE: Introduction

Authors
Vo-Dinh, T; Grundfest, WS; Benaron, DA; Cohn, GE
MLA Citation
Vo-Dinh, T, Grundfest, WS, Benaron, DA, and Cohn, GE. "Progress in Biomedical Optics and Imaging - Proceedings of SPIE: Introduction." Progress in Biomedical Optics and Imaging - Proceedings of SPIE 5692 (2005): xiii-.
Source
scival
Published In
Proceedings of SPIE
Volume
5692
Publish Date
2005
Start Page
xiii

Plasmonics-based nanostructures for surface-enhanced Raman scattering bioanalysis.

Surface-enhanced Raman scattering (SERS) spectroscopy is a plasmonics-based spectroscopic technique that combines modern laser spectroscopy with unique optical properties of metallic nanostructures, resulting in strongly increased Raman signals when molecules are adsorbed on or near nanometer-size structures of special metals such as gold, silver, and transition metals. This chapter provides a synopsis of the development and application of SERS-active metallic nanostructures, especially for the analysis of biologically relevant compounds. Some highlights of this chapter include reports of SERS as an immunoassay readout method, SERS gene nanoprobes, near-field scanning optical microscopy SERS probes, SERS as a tool for single-molecule detection, and SERS nanoprobes for cellular studies.

Authors
Vo-Dinh, T; Yan, F; Stokes, DL
MLA Citation
Vo-Dinh, T, Yan, F, and Stokes, DL. "Plasmonics-based nanostructures for surface-enhanced Raman scattering bioanalysis." Methods Mol Biol 300 (2005): 255-283. (Review)
PMID
15657488
Source
pubmed
Published In
Methods in molecular biology (Clifton, N.J.)
Volume
300
Publish Date
2005
Start Page
255
End Page
283
DOI
10.1385/1-59259-858-7:255

Studying 3D subdomains of proteins at the nanometer scale using fluorescence spectroscopy.

Databases devoted to the crystal structure of proteins have dramatically increased in size during the last two decades. Moreover, X-ray and NMR technology studies have shown that proteins belonging to the same family generally share the same global 3D architecture. These results suggest that the need for experimental determination of protein structure will be reduced to those that are suspected to have sufficiently novel structures. Furthermore, NMR and other techniques have demonstrated that a protein in solution experiences constant random thermal motions that occur over large time scales, ranging from picoseconds to seconds and perhaps hours. Such changes may have important functional consequences, but identifying which changes are functionally relevant remains a difficult task even if this problem has been addressed both with experimental and computational methods. For that specific purpose, there is a need for methods allowing a fast and accurate monitoring of conformation changes (that occur at specific sub-domains of proteins. Fluorescence resonance energy transfer (FRET) is a suitable tool for monitoring conformational changes at the nanoscale level. This chapter describes the various FRET methods that are used for monitoring the 3D sub-domain conformation of proteins in solution, in single living cells and at the single molecular level.

Authors
Viallet, PM; Vo-Dinh, T
MLA Citation
Viallet, PM, and Vo-Dinh, T. "Studying 3D subdomains of proteins at the nanometer scale using fluorescence spectroscopy." Methods Mol Biol 300 (2005): 165-189. (Review)
PMID
15657484
Source
pubmed
Published In
Methods in molecular biology (Clifton, N.J.)
Volume
300
Publish Date
2005
Start Page
165
End Page
189
DOI
10.1385/1-59259-858-7:165

Near-field scanning optical microscopy for bioanalysis at nanometer resolution.

The nondestructive imaging of biomolecules in nanometer domains in their original location and position as adsorbed or deposited on a surface is of garners considerable experimental interest. Near-field scanning optical microscopy (NSOM) is an emerging technique with its astonishing resolving power of <100-nm domains, and nondestructive nature compared with other scanning probe microscopic techniques is an emerging technique to achieve this goal. At the single-molecule level of resolution, it is possible to use the NSOM as a critical tool for visualization of proteins on surfaces to obtain more fundamental information about their orientation and locality without disturbing their original orientation and position, and level of interaction with the surface. Several areas of science and medicine can benefit from this type of study especially for biomedical and biochip applications. To illustrate possible applications, imaging of green fluorescent proteins and biomolecules associated with multidrug resistance proteins in tumor cells will be demonstrated using NSOM.

Authors
Wabuyele, MB; Culha, M; Griffin, GD; Viallet, PM; Vo-Dinh, T
MLA Citation
Wabuyele, MB, Culha, M, Griffin, GD, Viallet, PM, and Vo-Dinh, T. "Near-field scanning optical microscopy for bioanalysis at nanometer resolution." Methods Mol Biol 300 (2005): 437-452. (Review)
PMID
15657496
Source
pubmed
Published In
Methods in molecular biology (Clifton, N.J.)
Volume
300
Publish Date
2005
Start Page
437
End Page
452
DOI
10.1385/1-59259-858-7:437

Protein nanotechnology: the new frontier in biosciences.

The combination of nanotechnology and molecular biology has led to a new generation of nanoscale-based devices and methods for probing the cell machinery and elucidating intimate life processes occurring at the molecular level that were heretofore invisible to human inquiry. This chapter provides a brief overview of the field of nanotechnology and its applications to the study, design, and use of protein systems in biology and medicine.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Protein nanotechnology: the new frontier in biosciences." Methods Mol Biol 300 (2005): 1-13. (Review)
PMID
15657477
Source
pubmed
Published In
Methods in molecular biology (Clifton, N.J.)
Volume
300
Publish Date
2005
Start Page
1
End Page
13
DOI
10.1385/1-59259-858-7:001

Optical nanosensors for detecting proteins and biomarkers in individual living cells.

Recently, nanotechnology has been revolutionizing important areas in molecular biology and medicine, especially diagnostics and therapy at the molecular and cellular levels. The combination of nanotechnology, biology, advanced materials, and photonics opens up the possibility of detecting and manipulating atoms and molecules using nanodevices. This capability has the potential for a wide variety of medical uses at the cellular level. One of the most recent technological advances has been in the area of nanosensors. This chapter describes the principle of optical nanosensors, their development, and their applications for in vivo analysis of proteins and biomarkers in individual living cells. Nanosensors were fabricated with optical fibers pulled down to tips with distal ends in nanoscale dimensions. Nanosensors with immobilized bioreceptor probes (e.g., antibodies, enzyme substrate) that are selective to target analyte molecules are also referred to as nanobiosensors. Laser light is launched into the fiber, and the resulting evanescent field at the tip of the fiber is used to excite target molecules bound to the antibody molecules. A photometric detection system is used to detect the optical signal (e.g., fluorescence) originating from the analyte molecules or from the analyte-bioreceptor reaction.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Optical nanosensors for detecting proteins and biomarkers in individual living cells." Methods Mol Biol 300 (2005): 383-401. (Review)
PMID
15657493
Source
pubmed
Published In
Methods in molecular biology (Clifton, N.J.)
Volume
300
Publish Date
2005
Start Page
383
End Page
401
DOI
10.1385/1-59259-858-7:383

Protein amyloidose misfolding: mechanisms, detection, and pathological implications.

A variety of diseases result because of misfolded protein that deposits in extracellular space in the body. These deposits can be amorphous (disordered) or fibrillar (ordered). Inclusion bodies are an example of amorphous aggregates, and amyloid fibril is an example of fibrillar or ordered aggregates. In this chapter, we discuss a class of diseases caused by fibrillar aggregate deposits or amyloid fibrils called amyloidosis. We also review mechanisms by which different proteins misfold to form amyloid fibrils. Each amyloid fibril formed from a different protein causes a different disease by affecting a different organ in the body. However, the characteristics of different amyloid fibrils, namely structure and morphology, observed by electron microscopy and X-ray fiber diffraction appear to be quite similar in nature. We present therapeutic strategies developed to eliminate amyloid fibril formation. These strategies could possibly avert a whole class of fatal diseases caused by amyloid fibril deposition owing to similar characteristics of the amyloid fibrils.

Authors
Jeyashekar, NS; Sadana, A; Vo-Dinh, T
MLA Citation
Jeyashekar, NS, Sadana, A, and Vo-Dinh, T. "Protein amyloidose misfolding: mechanisms, detection, and pathological implications." Methods Mol Biol 300 (2005): 417-435. (Review)
PMID
15657495
Source
pubmed
Published In
Methods in molecular biology (Clifton, N.J.)
Volume
300
Publish Date
2005
Start Page
417
End Page
435
DOI
10.1385/1-59259-858-7:417

NanoBiotechnology: Editorial

Authors
Vo-Dinh, T; Laurell, T; Tamiya, E; Odom, D; Geronimo, J
MLA Citation
Vo-Dinh, T, Laurell, T, Tamiya, E, Odom, D, and Geronimo, J. "NanoBiotechnology: Editorial." Nanobiotechnology 1.4 (2005): 325--.
Source
scival
Published In
NanoBioTechnology
Volume
1
Issue
4
Publish Date
2005
Start Page
325-
DOI
10.1385/NBT:1:4:325

Welcome to NanoBio Euro 2005

Authors
Vo-Dinh, T; Laurell, T; Tamiya, E
MLA Citation
Vo-Dinh, T, Laurell, T, and Tamiya, E. "Welcome to NanoBio Euro 2005." Nanobiotechnology 1.3 (2005): 253--.
Source
scival
Published In
NanoBioTechnology
Volume
1
Issue
3
Publish Date
2005
Start Page
253-
DOI
10.1385/NBT:1:3:253

Applications of carbon nanotubes for cancer research

Carbon nanotubes have many unique properties such as high surface area, hollow cavities, and excellent mechanical and electrical properties. Interfacing carbon nanotubes with biological systems could lead to significant applications in various disease diagnoses. Significant progress in interfacing carbon nanotubes with biological materials has been made in key areas such as aqueous solubility, chemical and biological functionalization for biocompatibility and specificity, and electronic sensing of proteins. In addition, the bioconjugated nanotubes combined with the sensitive nanotube-based electronic devices would enable sensitive biosensors toward medical diagnostics. Furthermore, recent findings of improved cell membrane permeability for carbon nanotubes would also expand medical applications to therapeutics using carbon nanotubes as carriers in gene delivery systems. This article reviews the current trends in biological functionalization of carbon nanotubes and their potential applications for breast cancer diagnostics. The article also reports the applications of confocal microscopy for use in understanding the interactions of biological materials such as antibodies on carbon nanotubes that are specific to surface receptors in breast cancer cells. Furthermore, a nanotube-field-effect transistor is demonstrated for electronic sensing of antibodies that are specific to surface receptors in cancer cells. Copyright © 2005 Humana Press Inc. All rights of any nature whatsoever are reserved.

Authors
Teker, K; Sirdeshmukh, R; Sivakumar, K; Lu, S; Wickstrom, E; Wang, H-N; Vo-Dinh, T; Panchapakesan, B
MLA Citation
Teker, K, Sirdeshmukh, R, Sivakumar, K, Lu, S, Wickstrom, E, Wang, H-N, Vo-Dinh, T, and Panchapakesan, B. "Applications of carbon nanotubes for cancer research." Nanobiotechnology 1.2 (2005): 171-182.
Source
scival
Published In
NanoBioTechnology
Volume
1
Issue
2
Publish Date
2005
Start Page
171
End Page
182
DOI
10.1385/NBT:1:2:171

Photothermal treatment of human carcinoma cells using liposome-encapsulated gold nanoshells

We report the application of liposome-encapsulated gold nanoshells for in vitro photo-induced hyperthermia in human mammary carcinoma cells. In addition to evaluating their effects in vitro, we compared the application liposome-encapsulated gold nanoshells and free-standing gold nanoshells for NanoPhotoTherapy (NPT). NPT-induced hyperthermia was performed using a 785-nm near-infrared light from a diode laser and the in vitro effects were evaluated using nucleic acid molecular probes by fluorescence microscopy. Additionally, we monitored the effectiveness of NPT by detecting apoptosis via capase-9 activity. Copyright © 2005 Humana Press Inc. All rights of any nature whatsoever are reserved.

Authors
Kasili, PM; Vo-Dinh, T
MLA Citation
Kasili, PM, and Vo-Dinh, T. "Photothermal treatment of human carcinoma cells using liposome-encapsulated gold nanoshells." Nanobiotechnology 1.3 (2005): 245-252.
Source
scival
Published In
NanoBioTechnology
Volume
1
Issue
3
Publish Date
2005
Start Page
245
End Page
252
DOI
10.1385/NBT:1:3:245

Proceedings of SPIE - The International Society for Optical Engineering: Introduction

Authors
III, AJS; Christesen, SD; Combs, RJ; Vo-Dinh, T
MLA Citation
III, AJS, Christesen, SD, Combs, RJ, and Vo-Dinh, T. "Proceedings of SPIE - The International Society for Optical Engineering: Introduction." Proceedings of SPIE - The International Society for Optical Engineering 5994 (2005): ix-x.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5994
Publish Date
2005
Start Page
ix
End Page
x

Introduction to NanoBiotechnology

Authors
Vo-Dinh, T; Laurell, T; Tamiya, E
MLA Citation
Vo-Dinh, T, Laurell, T, and Tamiya, E. "Introduction to NanoBiotechnology." Nanobiotechnology 1.1 (2005): 1-2.
Source
scival
Published In
NanoBioTechnology
Volume
1
Issue
1
Publish Date
2005
Start Page
1
End Page
2
DOI
10.1385/Nano:1:1:1

Detection of cytochrome C in a single cell using an optical nanobiosensor.

In this work, the intracellular measurement of cytochrome c using an optical nanobiosensor is demonstrated. The nanobiosensor is a unique fiberoptics-based tool which allows the minimally invasive analysis of intracellular components. Cytochrome c is a very important protein to the process which produces cellular energy. In addition, cytochrome c is well-known as the protein involved in apoptosis, or programmed cell death. delta-Aminolevulinic acid (5-ALA) was used to induce apoptosis in MCF-7 human breast carcinoma cells. 5-ALA, a photodynamic therapy (PDT) drug in cells was activated by a HeNe laser beam. After the PDT photoactivation, the release of cytochrome c from the mitochondria to the cytoplasm in a MCF-7 cell was monitored by the optical nanobiosensor inserted inside the single cell and followed by an enzyme-linked immunosorbent assay (ELISA) outside the cell. The combination of the nanobiosensor with the ELISA immunoassay improved the detection sensitivity of the nanobiosensor due to enzymatic amplification. Our results lead to the investigation of an apoptotic pathway at the single cell level.

Authors
Song, JM; Kasili, PM; Griffin, GD; Vo-Dinh, T
MLA Citation
Song, JM, Kasili, PM, Griffin, GD, and Vo-Dinh, T. "Detection of cytochrome C in a single cell using an optical nanobiosensor." Anal Chem 76.9 (May 1, 2004): 2591-2594.
PMID
15117202
Source
pubmed
Published In
Analytical Chemistry
Volume
76
Issue
9
Publish Date
2004
Start Page
2591
End Page
2594
DOI
10.1021/ac0352878

Screening for the breast cancer gene (BRCA1) using a biochip system and molecular beacon probes immobilized on solid surfaces.

We describe the use of a biochip based on complementary metal oxide semiconductor (CMOS) technology for detection of specific genetic sequences using molecular beacons (MB) immobilized on solid surfaces as probes. The applicability of this miniature detection system for screening for the BRCA1 gene is evaluated using MB probes, designed especially for the BRCA1 gene. MB probes are immobilized on a zeta-probe membrane by biotin-streptavidin immobilization. Two immobilization strategies are investigated to obtain optimal assay sensitivity. The MB is immobilized by manual spotting on zeta-probe membrane surfaces with the use of a custom-made stamping system. The detection of the BRCA1 gene using an MB probe is successfully demonstrated and expands the use of the CMOS biochip for medical applications.

Authors
Culha, M; Stokes, DL; Griffin, GD; Vo-Dinh, T
MLA Citation
Culha, M, Stokes, DL, Griffin, GD, and Vo-Dinh, T. "Screening for the breast cancer gene (BRCA1) using a biochip system and molecular beacon probes immobilized on solid surfaces." J Biomed Opt 9.3 (May 2004): 439-443.
PMID
15189080
Source
pubmed
Published In
Journal of Biomedical Optics
Volume
9
Issue
3
Publish Date
2004
Start Page
439
End Page
443
DOI
10.1117/1.1691025

Application of a miniature biochip using the molecular beacon probe in breast cancer gene BRCA1 detection.

We report for the first time the application of a biochip using the molecular beacon (MB) detection scheme. The usability of this biochip novel detection system for the analysis of the breast cancer gene BRCA1 is demonstrated using molecular beacon probes. The MB is designed for the BRCA1 gene and a miniature biochip system is used for detection. The performance of the biochip-MB detection system is evaluated. The optimum conditions for the MB system for highest fluorescence detection sensitivity are investigated for the detection system. The detection of BRCA1 gene is successfully demonstrated in solution and the limit of detection (LOD) is estimated as 70 nM.

Authors
Culha, M; Stokes, DL; Griffin, GD; Vo-Dinh, T
MLA Citation
Culha, M, Stokes, DL, Griffin, GD, and Vo-Dinh, T. "Application of a miniature biochip using the molecular beacon probe in breast cancer gene BRCA1 detection." Biosens Bioelectron 19.9 (April 15, 2004): 1007-1012.
PMID
15018955
Source
pubmed
Published In
Biosensors and Bioelectronics
Volume
19
Issue
9
Publish Date
2004
Start Page
1007
End Page
1012
DOI
10.1016/j.bios.2003.09.006

Optical sensor for the detection of caspase-9 activity in a single cell.

We demonstrate for the first time, the application and utility of a unique optical sensor having a nanoprobe for monitoring the onset of the mitochondrial pathway of apoptosis in a single living cell by detecting enzymatic activities of caspase-9. Minimally invasive analysis of single live MCF-7 cells for caspase-9 activity is demonstrated using the optical sensor which employs a modification of an immunochemical assay format for the immobilization of nonfluorescent enzyme substrate, Leucine-GlutamicAcid-Histidine-AsparticAcid-7-amino-4-methylcoumarin (LEHD-AMC). LEHD-AMC covalently attached on the nanoprobe tip of an optical sensor is cleaved during apoptosis by caspase-9 generating free AMC. An evanescent field is used to excite cleaved AMC and the resulting fluorescence signal is detected. By quantitatively monitoring the changes in fluorescence signals, caspase-9 activity within a single living MCF-7 cell was detected. By comparing of the fluorescence signals from apoptotic cells induced by photodynamic treatment and nonapoptotic cells, we successfully detected caspase-9 activity, which indicates the onset of apoptosis in the cells.

Authors
Kasili, PM; Song, JM; Vo-Dinh, T
MLA Citation
Kasili, PM, Song, JM, and Vo-Dinh, T. "Optical sensor for the detection of caspase-9 activity in a single cell." J Am Chem Soc 126.9 (March 10, 2004): 2799-2806.
PMID
14995197
Source
pubmed
Published In
Journal of the American Chemical Society
Volume
126
Issue
9
Publish Date
2004
Start Page
2799
End Page
2806
DOI
10.1021/ja037388t

Surface-enhanced-Raman-scattering-inducing nanoprobe for spectrochemical analysis.

This paper describes a new nanoprobe that induces the surface-enhanced Raman scattering (SERS) effect when brought into contact with chemicals on any type of surface. The SERS-inducing probe was fabricated from an optical fiber that was tapered to a tip 100 nm in diameter. A thin layer of silver islands was applied to the tip of the tapered fiber via thermal evaporation to induce the SERS effect. The small scale of the tip may be amenable to localized, nondestructive SERS-based analyses of surfaces with high spatial selectivity. Because the contact probe itself induces the SERS effect, no modification of the sample is required. Direct analysis at submicrometer spatial selectivity is therefore possible for analyte compounds on any type of surface. Various optimization studies and preliminary evaluations were performed. A 10-nm silver thickness was determined to yield the optimum SERS effect. A 25% relative standard deviation in SERS signal was observed for five different probe tips. As a demonstration of the SERS-inducing capability of the probe, Raman spectra were recorded for glass surfaces coated with brilliant cresyl blue and p-aminobenzoic acid before and during contact with the SERS-inducing nanoprobe.

Authors
Stokes, DL; Chi, Z; Vo-Dinh, T
MLA Citation
Stokes, DL, Chi, Z, and Vo-Dinh, T. "Surface-enhanced-Raman-scattering-inducing nanoprobe for spectrochemical analysis." Appl Spectrosc 58.3 (March 2004): 292-298.
PMID
15035709
Source
pubmed
Published In
Applied spectroscopy
Volume
58
Issue
3
Publish Date
2004
Start Page
292
End Page
298
DOI
10.1366/000370204322886636

Implication of mitochondrial involvement in apoptotic activity of fragile histidine triad gene: application of synchronous luminescence spectroscopy.

The fragile histidine triad (FHIT) tumor suppressor gene incorporates the common human chromosomal fragile site at 3p14.2. The structure and expression of the FHIT gene are frequently altered in many cancers. The tumor suppressor activity of the FHIT gene has been previously demonstrated as potentially involving apoptotic induction. Here, mitochondria are implicated as being involved in the apoptotic activity of the FHIT gene. A number of morphological and biochemical events, including the disruption of the inner mitochondrial transmembrane potential (Delta Psi(m)) and the release of apoptogenic cytochrome c protein into the cytoplasm, are characteristic features of the apoptotic program. The proapoptotic activity of the FHIT gene is studied by investigating the loss of Delta Psi(m) in mitochondria and translocation of cytochrome c. Synchronous luminescence (SL) spectroscopy is applied to measure mitochondrial incorporation of rhodamine 123 for direct analysis of alterations in the mitochondrial Delta Psi(m). The SL methodology is based on synchronous excitation in which the excitation and emission wavelengths are scanned simultaneously while a constant wavelength interval is maintained between the excitation and emission monochromators. An enhanced collapse of Delta Psi(m) in apoptotically induced FHIT expressing cells compared to FHIT negative cells is observed. The loss of Delta Psi(m) is greatly restricted in the presence of the apoptotic inhibitor, cyclosporin A. Cytoplasmic translocation of cytochrome c in the FHIT expressing cells as an early event in apoptosis is also demonstrated. It is concluded that Fhit protein expression maintained apoptotic function by altering the Delta Psi(m) and by enhancing cytochrome c efflux from the mitochondria.

Authors
Askari, MDF; Vo-Dinh, T
MLA Citation
Askari, MDF, and Vo-Dinh, T. "Implication of mitochondrial involvement in apoptotic activity of fragile histidine triad gene: application of synchronous luminescence spectroscopy." Biopolymers 73.4 (March 2004): 510-523.
PMID
14991669
Source
pubmed
Published In
Biopolymers
Volume
73
Issue
4
Publish Date
2004
Start Page
510
End Page
523
DOI
10.1002/bip.10544

Proceedings of SPIE - The International Society for Optical Engineering: Introduction

Authors
Sedlacek, AJ; Christesen, SD; Colton, R; Vo-Dinh, T
MLA Citation
Sedlacek, AJ, Christesen, SD, Colton, R, and Vo-Dinh, T. "Proceedings of SPIE - The International Society for Optical Engineering: Introduction." January 1, 2004.
Source
scopus
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5269
Publish Date
2004

Metallic nanostructures for plasmonic sensors using surface-enhanced fluorescence and Raman detection

We present the fabrication and characterization of silver island films with SiO 2 coatings for application in plasmonic sensors based on surface-enhanced fluorescence and Raman detection. The emission spectral properties of goat anti-mouse immunoglobulin (IgG) F(ab′) 2 labeled with one or two fluorescein residues were examined on substrates with metallic silver islands. The self-quenching of fluorescein emission was mostly eliminated when this antibody fragment was held 60-90 A from the surface of metallic silver islands, and our preliminary experiments demonstrated an 8-fold emission intensity increase. Similar surfaces were also examined for surface-enhanced Raman analysis of Rhodamine 123, a potential drug for photodynamic therapy.

Authors
Yan, F; Wabuyele, MB; Griffin, GD; Vo-Dinh, T
MLA Citation
Yan, F, Wabuyele, MB, Griffin, GD, and Vo-Dinh, T. "Metallic nanostructures for plasmonic sensors using surface-enhanced fluorescence and Raman detection." Proceedings of SPIE - The International Society for Optical Engineering 5327 (2004): 53-59.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5327
Publish Date
2004
Start Page
53
End Page
59
DOI
10.1117/12.542455

A hyperspectral imaging system for in vivo optical diagnostics

Authors
Vo-Dinh, T; Stokes, DL; Wabuyre, MB; Martin, ME; Song, JM; Jagannathan, R; Michaud, E; Lee, RJ; Pan, X
MLA Citation
Vo-Dinh, T, Stokes, DL, Wabuyre, MB, Martin, ME, Song, JM, Jagannathan, R, Michaud, E, Lee, RJ, and Pan, X. "A hyperspectral imaging system for in vivo optical diagnostics." IEEE Engineering in Medicine and Biology Magazine 23.5 (2004): 40-49.
Source
scival
Published In
IEEE Engineering in Medicine and Biology Magazine
Volume
23
Issue
5
Publish Date
2004
Start Page
40
End Page
49
DOI
10.1109/MEMB.2004.1360407

Surface-enhanced Raman scattering (SERS) detection for chemical and biological agents

Surface-enhanced Raman scattering (SERS) spectra of chemical agent simulants such as dimethyl methylphonate (DMMP), pinacolyl methylphosphonate (PMP), diethyl phosphoramidate (DEPA), and 2-chloroethyl ethylsulfide (CEES), and biological agent simulants such as bacillus globigii (BG), erwinia herbicola (EH), and bacillus thuringiensis (BT) were obtained from silver oxide film-deposited substrates. Thin AgO films ranging in thickness from 50 nm to 250 nm were produced by chemical bath deposition onto glass slides. Further Raman intensity enhancements were noticed in UV irradiated surfaces due to photo-induced Ag nanocluster formation, which may provide a possible route to producing highly useful plasmonic sensors for the detection of chemical and biological agents upon visible light illumination.

Authors
Yan, F; Stokes, DL; Wabuyele, MB; Griffin, GD; Vass, AA; Vo-Dinh, T
MLA Citation
Yan, F, Stokes, DL, Wabuyele, MB, Griffin, GD, Vass, AA, and Vo-Dinh, T. "Surface-enhanced Raman scattering (SERS) detection for chemical and biological agents." Proceedings of SPIE - The International Society for Optical Engineering 5321 (2004): 302-308.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5321
Publish Date
2004
Start Page
302
End Page
308
DOI
10.1117/12.558478

Investigation of microfabrication of biological sample arrays using piezoelectric and bubble-jet printing technologies

Modified commercial ink-jet printers are simple and cost-effective tools for the fabrication of microarrays containing biological samples. In this paper, the two most common ink-dispensing technologies, thermal and piezoelectric, were investigated, tested, and compared in terms of their ease of use and spotting quality. Ink cartridges were used as sample reservoirs and refilled with small volumes (as low as 20 μL) of water-based sample solutions containing herring sperm DNA and fluorescent dyes. Different solution compositions were evaluated and compared. Microscopic spots (<200 μm) were printed on various membranes (cellulose, nylon, nitrocellulose, and Zeta-Probe) and glass microscope slides. This technique enabled rapid preparation of a large number of printed arrays of biological materials at extremely low cost. To further demonstrate the utility of the microarray platform, we performed an assay of Bacillus anthracis, detected through DNA hybridization using fluorescent probes complementary to the B. anthracis target printed on a membrane. A comparison of Zeta-Probe and nylon membranes yielded less non-specific binding when using the Zeta-Probe membrane. In addition, detection of 100 fmol of the target per printed spot was demonstrated. © 2004 Published by Elsevier B.V.

Authors
Allain, LR; Stratis-Cullum, DN; Vo-Dinh, T
MLA Citation
Allain, LR, Stratis-Cullum, DN, and Vo-Dinh, T. "Investigation of microfabrication of biological sample arrays using piezoelectric and bubble-jet printing technologies." Analytica Chimica Acta 518.1-2 (2004): 77-85.
Source
scival
Published In
Analytica Chimica Acta
Volume
518
Issue
1-2
Publish Date
2004
Start Page
77
End Page
85
DOI
10.1016/j.aca.2004.04.065

Single-board computer based control system for a portable Raman device with integrated chemical identification

A battery-powered portable chemical identification device built around an acousto-optic tunable filter (AOTF)-based Raman spectrometer was developed. The system was controlled by custom-developed software that works on an embedded single-board computer (SBC). It was found that the instrument could acquire spectra over a raman shift range of 238 to 1620 cm. It was observed that the embedded SBC-LCD control system facilitated the portability of the instrument and gave it great flexibility in tasking and implementing complex operating modules.

Authors
Mobley, J; Cullum, BM; Wintenberg, AL; Frank, SS; Maples, RA; Stokes, DL; Vo-Dinh, T
MLA Citation
Mobley, J, Cullum, BM, Wintenberg, AL, Frank, SS, Maples, RA, Stokes, DL, and Vo-Dinh, T. "Single-board computer based control system for a portable Raman device with integrated chemical identification." Review of Scientific Instruments 75.6 (2004): 2016-2023.
Source
scival
Published In
Review of Scientific Instruments
Volume
75
Issue
6
Publish Date
2004
Start Page
2016
End Page
2023
DOI
10.1063/1.1753670

Photochemically prepared gold metal film in a carbohydrate-based polymer: A practical solid substrate for surface-enhanced Raman scattering

A method for the preparation of thin gold film on glass slides has been described. When thin films of methylcellulose containing chloroauric acid are irradiated in a photoreactor under UV light, they produce a clear gold mirror made of aggregated gold particles stabilized by methylcellulose. The metal film can be used as a practical substrate for surface-enhanced Raman scattering. The substrate is stable and easy to prepare.

Authors
Pal, A; Stokes, DL; Vo-Dinh, T
MLA Citation
Pal, A, Stokes, DL, and Vo-Dinh, T. "Photochemically prepared gold metal film in a carbohydrate-based polymer: A practical solid substrate for surface-enhanced Raman scattering." Current Science 87.4 (2004): 486-491.
Source
scival
Published In
Current Science
Volume
87
Issue
4
Publish Date
2004
Start Page
486
End Page
491

Miniature biochip system for bioenvironmental applications

An integrated multi-functional biochip based on integrated circuit complementary metal oxide semiconductor (CMOS) sensor array for use in medical diagnostics and pathogen detection has been described. The usefulness and potential of the biochip as a rapid, inexpensive screening tool for detection of bioenvironmental pathogens will be demonstrated. Detection of aerosolized spores was achieved by coupling the miniature system to a portable bioaerosol sampler, and the performance of the antibody-based recognition and enzyme amplification method was evaluated. The bioassay performance was found to be compatible with the air sampling device, and the enzymatic amplification was found to be an attractive amplification method for detection of low spore concentrations. The combined portable bioaerosol sampler and miniature biochip system detected 100 B. globigii spores, corresponding to 17 aerosolized spores/L of air.

Authors
Wabuyele, MB; Yan, F; Martin, ME; Griffin, GD; Stokes, DL; Stratis-Cullum, DN; Mobley, J; Vass, AA; Vo-Dinh, T
MLA Citation
Wabuyele, MB, Yan, F, Martin, ME, Griffin, GD, Stokes, DL, Stratis-Cullum, DN, Mobley, J, Vass, AA, and Vo-Dinh, T. "Miniature biochip system for bioenvironmental applications." Proceedings of SPIE - The International Society for Optical Engineering 5586 (2004): 26-32.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5586
Publish Date
2004
Start Page
26
End Page
32
DOI
10.1117/12.580126

Miniature biochip system for detection of Escherichia coli O157:H7 based on antibody-immobilized capillary reactors and enzyme-linked immunosorbent assay

In this work, we report Escherichia coli O157:H7 detection using antibody-immobilized capillary reactors, enzyme-linked immunosorbent assay (ELISA), and a biochip system. ELISA selective immunological method to detect pathogenic bacteria. ELISA is also directly adaptable to a miniature biochip system that utilizes conventional sample platforms such as polymer membranes and glass. The antibody-immobilized capillary reactor is a very attractive sample platform for ELISA because of its low cost, compactness, reuse, and ease of regeneration. Moreover, an array of capillary reactors can provide high-throughput ELISA. In this report, we describe the use of an array of antibody-immobilized capillary reactors for multiplex detection of E. coli O157:H7 in our miniature biochip system. Side-entry laser beam irradiation to an array of capillary reactors contributes significantly to miniaturized optical configuration for this biochip system. The detection limits of E. coli O157:H7 using the ELISA and Cy5 label-based immunoassays were determined to be 3 and 230 cells, respectively. This system shows capability to simultaneously monitor multifunctional immunoassay and high sensitive detection of E. coli O157:H7. © 2003 Elsevier B.V. All rights reserved.

Authors
Song, JM; Vo-Dinh, T
MLA Citation
Song, JM, and Vo-Dinh, T. "Miniature biochip system for detection of Escherichia coli O157:H7 based on antibody-immobilized capillary reactors and enzyme-linked immunosorbent assay." Analytica Chimica Acta 507.1 (2004): 115-121.
Source
scival
Published In
Analytica Chimica Acta
Volume
507
Issue
1
Publish Date
2004
Start Page
115
End Page
121
DOI
10.1016/j.aca.2003.11.072

Portable Raman Integrated Tunable Sensor (RAMiTs) for environmental field monitoring

This paper describes a self-contained, portable Raman instrument that has been developed for environmental and homeland defense applications. The instrument consists of a 830-nm diode laser for excitation, an acousto-optic tunable filter (AOTF) for wavelength discrimination, and an avalanche photodiode for detection. The primary component of this system is the AOTF and it has been selected based on its spectral range along with its high resolution, ∼7.5 cm -1. Software has been developed in house using C programming language for controlling the instrument (i.e. the AOTF frequency, the signal acquisition, etc.). Evaluation of this instrument has been performed by analyzing several standard samples and comparing to a conventional Raman system. In addition to system evaluation, this paper will also discuss potential applications of this instrument to trace detection of hazardous chemicals using the Raman Integrated Tunable Sensor (RAMiTs) coupled with surface-enhance Raman scattering process.

Authors
Wabuyele, MB; Martin, ME; Yan, F; Stokes, DL; Mobley, J; Cullum, BM; Wintenberg, A; Lenarduzzi, R; Vo-Dinh, T
MLA Citation
Wabuyele, MB, Martin, ME, Yan, F, Stokes, DL, Mobley, J, Cullum, BM, Wintenberg, A, Lenarduzzi, R, and Vo-Dinh, T. "Portable Raman Integrated Tunable Sensor (RAMiTs) for environmental field monitoring." Proceedings of SPIE - The International Society for Optical Engineering 5586 (2004): 60-67.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5586
Publish Date
2004
Start Page
60
End Page
67
DOI
10.1117/12.580125

Detection of polycyclic aromatic compounds in single living cells using optical nanoprobes

Exposure of mammalian cells to polycyclic aromatic compounds (PACs) such as the carcinogen benzo[a]pyrene (BaP) leads to the formation of DNA adducts N2-deoxyguanosine (dG) and N6-deoxyadenosine (dA) with adenine and guanine nucleotides, which are integral parts of DNA, RNA, and ATP. DNA adduct formation causes alteration of the DNA (RNA) sequence since neither adenine nor guanine can normally bind to its complementary nucleotide base, thymine (uracil) and cytosine respectively. The inability to form these bonds leads to mutations in the DNA double-helix structure during DNA replication, and eventually carcinogenesis. Therefore, the capability to detect and measure PAC species such as BaP in single living cells is important for studies required to establish the limits of BaP exposure necessary for carcinogenesis. Along these lines, we have developed antibody-based optical nanoprobes capable of detecting and measuring BaP in single living cells. The results obtained in this work demonstrate the practical application of antibody-based nanoprobes for performing measurements inside single living cells with their elements and their relationships intact.

Authors
Kasili, PM; Vo-Dinh, T
MLA Citation
Kasili, PM, and Vo-Dinh, T. "Detection of polycyclic aromatic compounds in single living cells using optical nanoprobes." Polycyclic Aromatic Compounds 24.3 (2004): 221-235.
Source
scival
Published In
Polycyclic Aromatic Compounds
Volume
24
Issue
3
Publish Date
2004
Start Page
221
End Page
235
DOI
10.1080/10406630490460700

IV.3 Remote monitors for in situ characterization of hazardous wastes

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "IV.3 Remote monitors for in situ characterization of hazardous wastes." Waste Management Series 4.C (2004): 485-502.
Source
scival
Published In
Waste Management Series
Volume
4
Issue
C
Publish Date
2004
Start Page
485
End Page
502
DOI
10.1016/S0713-2743(04)80019-9

Advanced biophotonics: From biochips to nanosensors

This lecture provides an overview of the research activities in our laboratory related to the development and application of advanced biomedical photonics, molecular spectroscopy, nanosensors and biochips for biomedical diagnostics. © 2004 IEEE.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Advanced biophotonics: From biochips to nanosensors." Second Asian and Pacific Rim Symposium on Biophotonics - Proceedings, APBP 2004 (2004): 4-5.
Source
scival
Published In
Second Asian and Pacific Rim Symposium on Biophotonics - Proceedings, APBP 2004
Publish Date
2004
Start Page
4
End Page
5

Proceedings of SPIE - The International Society for Optical Engineering: Introduction

Authors
III, AJS; Christesen, SD; Colton, R; Vo-Dinh, T
MLA Citation
III, AJS, Christesen, SD, Colton, R, and Vo-Dinh, T. "Proceedings of SPIE - The International Society for Optical Engineering: Introduction." Proceedings of SPIE - The International Society for Optical Engineering 5269 (2004): ix-.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
5269
Publish Date
2004
Start Page
ix

Medical biophotonics: From lasers to blochips

Medical use of biophotonics for therapeutic and diagnostic purposes was discussed. Nanoparticle based surface-enhanced Raman scattering (SERS) technology enabled sensitive detection of a variety of compounds of environmental and medical interest. Biosensors were found to be capable of detecting and differentiating bio/chemical constituents of complex systems for identification and accurate quantitation of chemical and biological sensing. It was also observed that the biochip can be use to diagnose genetic susceptibility and diseases and can also be used to monitor exposure to biological pathogens and to bioactive environmental samples.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Medical biophotonics: From lasers to blochips." Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS 2 (2004): 961-962.
Source
scival
Published In
Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS
Volume
2
Publish Date
2004
Start Page
961
End Page
962

Optical Nanosensors for Biological Applications-Spectroscopic Techniques at the Cellular Level

© 2003 Elsevier Inc. All rights reserved.This chapter describes the basic principles of optical-based biosensors as well as discusses the evolution of the relatively new class of biosensors with nanometer dimensions and their application to the monitoring of biological species on the cellular level. A biosensor can be generally defined as a device that consists of a biological recognition element, often called a bioreceptor, and a transducer. Despite the wide variety of bioreceptors and transducers employed, they are all based on the same principle. First, the sensor is placed in the environment of interest, where the target molecules bind to the bioreceptors in the biosensitive layer of the sensor. Bioreceptors can be biological molecules such as antibodies, enzymes, non-enzymatic proteins, nucleic acids or living biological systems such as cells, tissues, or whole organisms. The resulting interaction between the analyte and the bioreceptor then produces an effect that can be measured by the transducer, which converts this effect into some type of measurable signal (e.g., such as an electrical voltage).

Authors
Cullum, BM; Vo-Dinh, T
MLA Citation
Cullum, BM, and Vo-Dinh, T. "Optical Nanosensors for Biological Applications-Spectroscopic Techniques at the Cellular Level." (December 19, 2003): 225-250. (Chapter)
Source
scopus
Publish Date
2003
Start Page
225
End Page
250
DOI
10.1016/B978-012507060-7/50025-8

Introduction

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Introduction." Proceedings of SPIE - The International Society for Optical Engineering 4958 (December 5, 2003).
Source
scopus
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4958
Publish Date
2003

Development of a fluorescence detection system using optical parametric oscillator (OPO) laser excitation for in vivo diagnosis.

In this work, the development and applications of a fluorescence detection system using optical parametric oscillator (OPO) laser excitation for in vivo disease diagnosis including oral carcinoma are described. The optical diagnosis system was based on an OPO laser for multi-wavelength excitation and time-resolved detection. The pulsed Nd-YAG-pumped OPO laser system (6 ns, 20 Hz) is compact and has a rapid, broad, and uniform tuning range. Time-gated detection of intensified charge-coupled device (ICCD) making use of external triggering was used to effectively eliminate the laser scattering and contribute to the highly sensitive in vivo measurements. Artificial tissue-simulating phantoms consisting of polystyrene microspheres and tissue fluorophores were tested to optimize the gating parameters. 51-ns gate width and 39-ns gate delays were determined to be the optimal parameters for sensitive detection. In vivo measurements with the optical diagnosis system were applied to esophagus, stomach, and small intestine using an endoscope in canine animal studies. The rapid tuning capability of the optical diagnosis system contributed greatly to the optimization of wavelength for the observation of porphyrin in the small intestine. When the small intestine was thoroughly washed with water, the emission band which corresponds to porphyrin disappeared. Based on this observation, it was concluded that the detected signal was yielded by porphyrin-containing bile secretion. Also, multispectral analyses using multiple excitations from 415 to 480 nm at 5 nm intervals confirmed the porphyrin detection in the small intestine. The optical diagnosis system was also applied to the detection of human xenograft of oral carcinoma in mice using 5-aminolevulinic acid (5-ALA) which is a photodynamic therapy (PDT) drug. Significant differences in protoporphyrin IX fluorescence intensity between normal and tumor tissue could be obtained 2 hours after the injection of 5-ALA into mice due to the preferential accumulation of 5-ALA in tumors. Results reported herein demonstrate potential capabilities of the LIF-OPO system for in vivo disease diagnosis.

Authors
Song, JM; Jagannathan, R; Stokes, DL; Kasili, PM; Panjehpour, M; Phan, MN; Overholt, BF; DeNovo, RC; Pan, X; Lee, RJ; Vo-Dinh, T
MLA Citation
Song, JM, Jagannathan, R, Stokes, DL, Kasili, PM, Panjehpour, M, Phan, MN, Overholt, BF, DeNovo, RC, Pan, X, Lee, RJ, and Vo-Dinh, T. "Development of a fluorescence detection system using optical parametric oscillator (OPO) laser excitation for in vivo diagnosis." Technol Cancer Res Treat 2.6 (December 2003): 515-523.
PMID
14640763
Source
pubmed
Published In
Technology in cancer research & treatment
Volume
2
Issue
6
Publish Date
2003
Start Page
515
End Page
523
DOI
10.1177/153303460300200604

Surface-enhanced Raman scattering substrate based on a self-assembled monolayer for use in gene diagnostics.

The development of surface-enhanced Raman scattering (SERS)-active substrates for cancer gene detection is described. The detection method uses Raman active dye-labeled DNA gene probes, self-assembled monolayers, and nanostructured metallic substrates as SERS-active platforms. The mercaptohexane-labeled single-stranded DNA (SH-(CH(2))(6)-ssDNA)/6-mercapto-1-hexanol system formed on a silver surface is characterized by atomic force microscopy. The surface-enhanced Raman gene (SERGen) probes developed in this study can be used to detect DNA targets via hybridization to complementary DNA probes. The probes do not require the use of radioactive labels and have a great potential to provide both sensitivity and selectivity. The effectiveness of this approach and its application in cancer gene diagnostics (BRCA1 breast cancer gene) are investigated.

Authors
Culha, M; Stokes, D; Allain, LR; Vo-Dinh, T
MLA Citation
Culha, M, Stokes, D, Allain, LR, and Vo-Dinh, T. "Surface-enhanced Raman scattering substrate based on a self-assembled monolayer for use in gene diagnostics." Anal Chem 75.22 (November 15, 2003): 6196-6201.
PMID
14616001
Source
pubmed
Published In
Analytical Chemistry
Volume
75
Issue
22
Publish Date
2003
Start Page
6196
End Page
6201
DOI
10.1021/ac0346003

Optoacoustic diffraction tomography: analysis of algorithms.

We consider the problem of using the photoacoustic effect to image the optical properties of tissue. A region of tissue is assumed to be illuminated by frequency-modulated light that creates an ultrasonic wave of the same frequency. This wave is detected on a passive array of receiving transducers distributed over a circular or a cylindrical aperture. If the frequency is swept over a broad band (or, equivalently, if we illuminate with a pulse and Fourier transform the response), then a spatial map of a parameter that depends on the optical absorption coefficient of the tissue can be recovered. Analytical inversion formulas are derived in both two and three dimensions. The effects of band-limited data on image quality are also investigated.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Optoacoustic diffraction tomography: analysis of algorithms." J Opt Soc Am A Opt Image Sci Vis 20.10 (October 2003): 1859-1866.
PMID
14570099
Source
pubmed
Published In
Journal of the Optical Society of America A
Volume
20
Issue
10
Publish Date
2003
Start Page
1859
End Page
1866

Monitoring intracellular proteins using fluorescence techniques: from protein synthesis and localization to activity.

The recent breakthroughs in genomics and proteomics and improvements of optical methods have made it possible to obtain localized, real-time information on intracellular proteins dynamics, through dynamic three-dimensional (3D) maps of the living cell with nanometric resolution of individual molecules. On one side, brighter variants of the Green Fluorescence Protein (GFP) have been engineered that have different excitation and/or emission spectra that better match available light sources. Like their parent molecule, these variants retain their fluorescence when fused to heterologous proteins on the N- and C- terminals, and this binding generally does not affect the functionality of the tagged protein leading the way to their use as an intracellular reporter. On the other side, optical methods have been improved to allow reaching the level of single-molecule detection inside living cells. Nevertheless some limitations exist for the use of GFP variants for probing 3D conformational changes of proteins. First, these variants are fused to the N and/or C terminals of the studied protein, which are generally not the best location to detect conformational changes resulting from the binding to other proteins or enzyme substrates. Then their own relatively large size makes them unusable for tagging small proteins. These limitations suggest that new tagging processes, permitting the location of the right fluorescent markers at the right places, must be found to built up inter- and/or intra-molecular rulers allowing one to monitor conformational changes resulting from intracellular protein-protein, protein-membrane, and enzyme-substrate binding. These specific locations can be obtained from in vitro studies of 3D conformational changes that occur during protein docking.

Authors
Viallet, PM; Vo-Dinh, T
MLA Citation
Viallet, PM, and Vo-Dinh, T. "Monitoring intracellular proteins using fluorescence techniques: from protein synthesis and localization to activity." Curr Protein Pept Sci 4.5 (October 2003): 375-388. (Review)
PMID
14529531
Source
pubmed
Published In
Current protein & peptide science
Volume
4
Issue
5
Publish Date
2003
Start Page
375
End Page
388

Experimental and numerical analysis of short-pulse laser interaction with tissue phantoms containing inhomogeneities.

The objective is to perform an experimental and numerical study to analyze short-pulse laser propagation through tissue phantoms without and with inhomogeneities embedded in them. For a short-pulse laser the observed optical signal has a distinct temporal shape, and the shape is a function of the medium properties. The scattered temporal transmitted and reflected optical signals are measured experimentally with a streak camera for tissue phantoms irradiated with a short-pulse laser source. A parametric study involving different scattering and absorption coefficients of tissue phantoms and inhomogeneities, as well as the detector positions and orientations, is performed. The temporal and spatial profiles of the scattered optical signals are compared with the numerical modeling results obtained by solving the transient radiative transport equation by using the discrete ordinates technique.

Authors
Das, C; Trivedi, A; Mitra, K; Vo-Dinh, T
MLA Citation
Das, C, Trivedi, A, Mitra, K, and Vo-Dinh, T. "Experimental and numerical analysis of short-pulse laser interaction with tissue phantoms containing inhomogeneities." Appl Opt 42.25 (September 1, 2003): 5173-5180.
PMID
12962398
Source
pubmed
Published In
Applied Optics
Volume
42
Issue
25
Publish Date
2003
Start Page
5173
End Page
5180

Surface-enhanced Raman scattering for cancer diagnostics: detection of the BCL2 gene.

A method of detection for cancer genes, such as B-cell lymphoma 2 gene, has been developed using surface-enhanced Raman scattering-active substrates. This method uses Raman active dye-labeled DNA gene probes and metallic nanostructures as surface-enhanced Raman scattering-active platforms. A self-assembled monolayer system composed of mercapto hexane-labeled, single-strand DNA (SH-(CH2)6-ssDNA/ 6-mercapto-1-hexanol) is formed on a silver surface. The Raman-active dye-labeled gene is hybridized with its complementary probe, which is immobilized on the silver surface. The surface-enhanced Raman gene probes in this study can be used to detect DNA targets via hybridization to complementary DNA probes. The probes do not involve the use of radioactive labels and have great potential to provide both sensitivity and selectivity. The utility of this approach is investigated.

Authors
Culha, M; Stokes, D; Vo-Dinh, T
MLA Citation
Culha, M, Stokes, D, and Vo-Dinh, T. "Surface-enhanced Raman scattering for cancer diagnostics: detection of the BCL2 gene." Expert Rev Mol Diagn 3.5 (September 2003): 669-675.
PMID
14510186
Source
pubmed
Published In
Expert Review of Molecular Diagnostics: new diagnostic technologies are set to revolutionise healthcare
Volume
3
Issue
5
Publish Date
2003
Start Page
669
End Page
675
DOI
10.1586/14737159.3.5.669

Detection of bacterial pathogen DNA using an integrated complementary metal oxide semiconductor microchip system with capillary array electrophoresis.

In this paper, we show an integrated complementary metal oxide semiconductor (CMOS)-based microchip system with capillary array electrophoresis (CAE) for the detection of bacterial pathogen amplified by polymerase chain reaction (PCR). In order to demonstrate the efficacy of PCR reaction for the heat-labile toxin producing enterotoxigenic Escherichia coli (E. coli), which causes cholera-like diarrhea, 100 bp DNA ladders were injected along with the PCR product. Poly(vinylpyrrolidone) (PVP) was used as the separation medium and provided separation resolution which was adequate for the identification of PCR product. The miniaturized integrated CMOS microchip system with CAE has excellent advantages over conventional instrumental systems for analysis of bacterial pathogens such as compactness, low cost, high speed, and multiplex capability. Furthermore, the miniaturized integrated CMOS microchip system should be compatible with a variety of microfabricated devices that aim at more rapid and high-throughput analysis.

Authors
Myong Song, J; Mobley, J; Vo-Dinh, T
MLA Citation
Myong Song, J, Mobley, J, and Vo-Dinh, T. "Detection of bacterial pathogen DNA using an integrated complementary metal oxide semiconductor microchip system with capillary array electrophoresis." J Chromatogr B Analyt Technol Biomed Life Sci 783.2 (January 15, 2003): 501-508.
PMID
12482493
Source
pubmed
Published In
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
Volume
783
Issue
2
Publish Date
2003
Start Page
501
End Page
508

A miniature biochip system for detection of aerosolized Bacillus globigii spores.

The feasibility of using a novel detection scheme for the analysis of biological warfare agents is demonstrated using Bacillus globigii spores, a surrogate species for Bacillus anthracis. In this paper, a sensitive and selective enzyme-linked immunosorbent assay using a novel fluorogenic alkaline phosphatase substrate (dimethylacridinone phosphate) is combined with a compact biochip detection system, which includes a miniature diode laser for excitation. Detection of aerosolized spores was achieved by coupling the miniature system to a portable bioaerosol sampler, and the performance of the antibody-based recognition and enzyme amplification method was evaluated. The bioassay performance was found to be compatible with the air sampling device, and the enzymatic amplification was found to be an attractive amplification method for detection of low spore concentrations. The combined portable bioaerosol sampler and miniature biochip system detected 100 B. globigii spores, corresponding to 17 aerosolized spores/L of air. Moreover, the incorporation of the miniature diode laser with the self-contained biochip design allows for a compact system that is readily adaptable to field use. In addition, these studies have included investigations into the tradeoff between assay time and sensitivity.

Authors
Stratis-Cullum, DN; Griffin, GD; Mobley, J; Vass, AA; Vo-Dinh, T
MLA Citation
Stratis-Cullum, DN, Griffin, GD, Mobley, J, Vass, AA, and Vo-Dinh, T. "A miniature biochip system for detection of aerosolized Bacillus globigii spores." Anal Chem 75.2 (January 15, 2003): 275-280.
PMID
12553762
Source
pubmed
Published In
Analytical Chemistry
Volume
75
Issue
2
Publish Date
2003
Start Page
275
End Page
280

Multi-functional biochip for biological agent detection

There is an increasing need to develop rapid, simple, cost-effective sensor devices for screening multiple pathogens for homeland defense applications. With its multifunctional capability, the multifunctional biochip (MFB) is a unique system that allows simultaneous detection of multiple biotargets simultaneously. Such a device could provide information on both gene mutation (with DNA probes) and gene expression (with antibody probes against proteins) simultaneously.

Authors
Vo-Dinh, T; Griffin, GD; Wintenberg, AL; Stokes, DT; Stratis, D; Mobley, J; Maples, R
MLA Citation
Vo-Dinh, T, Griffin, GD, Wintenberg, AL, Stokes, DT, Stratis, D, Mobley, J, and Maples, R. "Multi-functional biochip for biological agent detection." January 1, 2003.
Source
scopus
Published In
2003 International Semiconductor Device Research Symposium, ISDRS 2003 - Proceedings
Publish Date
2003
Start Page
495
DOI
10.1109/ISDRS.2003.1272222

Real-time detection of PAH mixtures in the vapor phase at high temperatures

Laser-induced fluorescence (LIF) spectroscopy can serve as a rapid analytical method for the quantitative analysis of polycyclic aromatic hydrocarbons (PAHs). The high quantum yields of this class of compounds, along with large absorption cross-sections, make fluorescence a very attractive technique for trace analysis determination of PAHs. Furthermore, fluorescence can provide in situ and online information regarding the composition and concentration of PAHs formed during combustion or pyrolysis processes. In this paper, we utilize a fiber-optic probe coupled to a spectrometer to collect fluorescence spectra of several PAH vapors at elevated temperatures using excitation at 337 nm. We have collected the fluorescence of standards as well as complex mixtures of PAHs at 300 °C. The expected band broadening induced by temperature effects was observed, but did not compromise the spectrum signature for each PAH studied. We have measured fluorescence spectra of benzo[a]pyrene, pyrene, anthracene, and phenanthrene vapors. Determination of trace amounts of the toxicologically important benzo[a]pyrene has been shown to be feasible. Experimental results show that at 337 nm, benzo[a]pyrene is the most quantum efficient fluorophore among the PAHs studied. Furthermore, fluorescence lifetime measurements were found to be helpful in the characterization of PAH mixtures. © 2002 Elsevier Science B.V. All rights reserved.

Authors
Allain, LR; Stratis, DN; Cullum, BM; Mobley, J; Hajaligol, MR; Vo-Dinh, T
MLA Citation
Allain, LR, Stratis, DN, Cullum, BM, Mobley, J, Hajaligol, MR, and Vo-Dinh, T. "Real-time detection of PAH mixtures in the vapor phase at high temperatures." January 1, 2003.
Source
scopus
Published In
Journal of Analytical and Applied Pyrolysis
Volume
66
Issue
1
Publish Date
2003
Start Page
145
End Page
154

Multi-analyte analysis system using an antibody-based biochip.

A multi-analyte detection system using a unique antibody (Ab) biochip is described. The Ab-based biochip, also referred to as the protein biochip, uses a sensor array based on a complementary metal oxide silicon (CMOS) integrated circuit. The Ab-biochip has a sampling platform of four-by-four microarrays of antibodies deposited onto a Nylon membrane substrate. The micro-arrayed antibodies can be interrogated simultaneously or sequentially using the biochip sensing array detector with the use of a diffractive optical element illuminating each antibody spot individually. The usefulness of the Ab biochip is illustrated by the measurements of immunoglobulin G (IgG) used as the model analyte system. The detection limit for Cy5-labeled IgG molecules was 13 pg.

Authors
Moreno-Bondi, MC; Alarie, JP; Vo-Dinh, T
MLA Citation
Moreno-Bondi, MC, Alarie, JP, and Vo-Dinh, T. "Multi-analyte analysis system using an antibody-based biochip." Anal Bioanal Chem 375.1 (January 2003): 120-124.
PMID
12520447
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
375
Issue
1
Publish Date
2003
Start Page
120
End Page
124
DOI
10.1007/s00216-002-1626-y

Application of an integrated microchip system with capillary array electrophoresis to optimization of enzymatic reactions

In this work, a combination of complementary metal-oxide semiconductor (CMOS) microchip system with capillary array electrophoresis (CAE) is demonstrated as a system for optimizing conditions for enzymatic reaction. Dimethylacridinone (DDAO)-phosphate substrate and alkaline phosphatase conjugate were selected for the enzymatic reaction, which was applicable to the enzyme-linked immunosorbent assay (ELISA) technique. Laser-induced fluorometry with a miniature semiconductor laser was used to detect the enzymatic products. The speed of the enzymatic reaction between the DDAO-phosphate and the alkaline phosphatase conjugate was investigated as a function of reaction time. The microchip-CAE detection system could determine the pH condition and the concentration of enzyme that are suitable for rapid and low-cost analysis. This result shows the feasibility of using the microchip-CAE system for application to miniaturized screening systems. © 2003 Elsevier Science B.V. All rights reserved.

Authors
Song, JM; Griffin, GD; Vo-Dinh, T
MLA Citation
Song, JM, Griffin, GD, and Vo-Dinh, T. "Application of an integrated microchip system with capillary array electrophoresis to optimization of enzymatic reactions." Analytica Chimica Acta 487.1 (2003): 75-82.
Source
scival
Published In
Analytica Chimica Acta
Volume
487
Issue
1
Publish Date
2003
Start Page
75
End Page
82
DOI
10.1016/S0003-2670(03)00515-4

Development of a multi-spectral imaging system for medical applications

We describe the development of a multi-spectral imaging (MSI) system based on a rapid-scanning solid-state device, an acousto-optic tunable filter (AOTF), for wavelength selection and a two-dimensional charge-coupled device for detection. The MSI device is designed for in vivo optical detection in medical diagnostic applications. Unlike conventional grating spectrometers, the AOTF is a miniature solid-state device that has no moving parts, and can be rapidly tuned to any wavelength within its operating range. The large aperture of the AOTF and its high spatial resolution allows the optical image from an imaging fibre optic probe to be recorded by the detector. These characteristics, combined with their small size, make AOTFs important new alternatives to conventional monochromators, especially for spectral imaging in biomedical applications. The MSI can also be used for dual-modality diagnostics to detect both fluorescence and diffuse reflectance images. The usefulness and potential of the MSI system is illustrated in several applications of biomedical interest, such as reflectance fluorescence imaging of skin and brain tissues.

Authors
Vo-Dinh, T; Cullum, B; Kasili, P
MLA Citation
Vo-Dinh, T, Cullum, B, and Kasili, P. "Development of a multi-spectral imaging system for medical applications." Journal of Physics D: Applied Physics 36.14 (2003): 1663-1668.
Source
scival
Published In
Journal of Physics D: Applied Physics
Volume
36
Issue
14
Publish Date
2003
Start Page
1663
End Page
1668
DOI
10.1088/0022-3727/36/14/302

Short pulse laser propagation through tissues

An experimental and numerical study is performed to analyze short pulse laser propagation through tissue phantoms without and with inhomogeneities/tumors imbedded in it. Short pulse laser probing techniques has distinct advantages over conventional very large pulse width or cw lasers primarily due to the additional information conveyed about the tissue interior by the temporal variation of the observed signal. Both the scattered temporal transmitted and reflected optical signals are measured experimentally using a streak camera for samples irradiated with a short pulse laser source. Parametric study involving different scattering and absorption coefficients of tissue phantoms and inhomogeneities as well as the detector position and orientation is performed. The temporal and spatial profiles of the scattered optical signals are compared with the numerical modeling results obtained by solving the transient radiative transport equation using discrete ordinates technique.

Authors
Das, C; Trivedi, A; Mitra, K; Vo-Dinh, T
MLA Citation
Das, C, Trivedi, A, Mitra, K, and Vo-Dinh, T. "Short pulse laser propagation through tissues." Proceedings of SPIE - The International Society for Optical Engineering 4958 (2003): 126-136.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4958
Publish Date
2003
Start Page
126
End Page
136
DOI
10.1117/12.497340

Biochip using a biofluidic system for detection of E. coli and other pathogens

This work provides an overview of progress made, in our laboratory, towards the development of a practical biochip-based technology with a biofluidics system for the detection of E. coli and other pathogens. Efforts have been devoted towards efficient coupling between a compact biofluidics sample/reagent delivery system and an integrated circuit (1C) biochip, consisting of a 2-dimensional photosensor array, for on-chip monitoring of bioassays. The complementary metal-oxide semiconductor (CMOS) technology has been implemented to design and produce the 1C biochip, which features a 4×4 array of independently addressable photodiodes that are integrated with amplifiers, discriminators and logic circuitry on a single platform. The CMOS-based biochip offers the advantages of compactness and low power consumption, making it better suited for field use than other array detectors, including CCDs. The biofluidics system includes a 0.4 mL hybridization chamber, which accommodates disposable sampling platforms embedded with bioreceptors for selective capture of pathogen DNA, proteins, or antibodies in discrete zones. The independently operating photodiodes of the 1C biochip offer the capability of monitoring of multiple assays. Highlights of this work include highly sensitive detection of E. coli (<50 organisms) and quantitative capability with a linear dynamic range of 3-5 orders of magnitude for various assays.

Authors
Stokes, DL; Allain, L; Griffin, GD; Mobley, J; Stratis-Cullum, DN; Wintenberg, AL; Maples, RA; Vo-Dinh, T
MLA Citation
Stokes, DL, Allain, L, Griffin, GD, Mobley, J, Stratis-Cullum, DN, Wintenberg, AL, Maples, RA, and Vo-Dinh, T. "Biochip using a biofluidic system for detection of E. coli and other pathogens." Proceedings of SPIE - The International Society for Optical Engineering 4958 (2003): 13-21.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4958
Publish Date
2003
Start Page
13
End Page
21
DOI
10.1117/12.488677

Laser-induced fluorescence for the detection of esophageal and skin cancer

Laser-induced fluorescence (LIF) is used for in-vivo cancer diagnosis of the esophagus and skin cancer. For esophageal measurements a fiberoptic probe inserted through an endoscope was used. Autofluorescence of normal and malignant tissues were measured directly on patient skin without requiring an endoscope. Measurement of the fluorescence signal from the tissue was performed using laser excitation at 410 nm. The methodology was applied to differentiate normal and malignant tumors of the esophagus and malignant skin lesions. The results of this LIF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal and malignant tumors for the samples investigated.

Authors
Vo-Dinh, T; Panjehpour, M; Overholt, BF; Julius, C; Overholt, S; Phan, MN
MLA Citation
Vo-Dinh, T, Panjehpour, M, Overholt, BF, Julius, C, Overholt, S, and Phan, MN. "Laser-induced fluorescence for the detection of esophageal and skin cancer." Proceedings of SPIE - The International Society for Optical Engineering 4958 (2003): 67-70.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4958
Publish Date
2003
Start Page
67
End Page
70
DOI
10.1117/12.488678

Real-time detection of PAH mixtures in the vapor phase at high temperatures

Laser-induced fluorescence (LIF) spectroscopy can serve as a rapid analytical method for the quantitative analysis of polycyclic aromatic hydrocarbons (PAHs). The high quantum yields of this class of compounds, along with large absorption cross-sections, make fluorescence a very attractive technique for trace analysis determination of PAHs. Furthermore, fluorescence can provide in situ and online information regarding the composition and concentration of PAHs formed during combustion or pyrolysis processes. In this paper, we utilize a fiber-optic probe coupled to a spectrometer to collect fluorescence spectra of several PAH vapors at elevated temperatures using excitation at 337 nm. We have collected the fluorescence of standards as well as complex mixtures of PAHs at 300 °C. The expected band broadening induced by temperature effects was observed, but did not compromise the spectrum signature for each PAH studied. We have measured fluorescence spectra of benzo[a]pyrene, pyrene, anthracene, and phenanthrene vapors. Determination of trace amounts of the toxicologically important benzo[a]pyrene has been shown to be feasible. Experimental results show that at 337 nm, benzo[a]pyrene is the most quantum efficient fluorophore among the PAHs studied. Furthermore, fluorescence lifetime measurements were found to be helpful in the characterization of PAH mixtures. © 2002 Elsevier Science B.V. All rights reserved.

Authors
Allain, LR; Stratis, DN; Cullum, BM; Mobley, J; Hajaligol, MR; Vo-Dinh, T
MLA Citation
Allain, LR, Stratis, DN, Cullum, BM, Mobley, J, Hajaligol, MR, and Vo-Dinh, T. "Real-time detection of PAH mixtures in the vapor phase at high temperatures." Journal of Analytical and Applied Pyrolysis 66.1 (2003): 145-154.
Source
scival
Published In
Journal of Analytical and Applied Pyrolysis
Volume
66
Issue
1
Publish Date
2003
Start Page
145
End Page
154

SERS gene probe for DNA diagnostics

We describe the development of a surface-enhanced Raman scattering gene (SERGen) probe technology for rapid screening for diseases and pathogens through DNA hybridization assays. The technology combines the use of gene probes labeled with SERS-active markers, and nanostructured metallic platforms for inducing the SERS effect. As a result, SERGen-based methods can offer the spectral selectivity and sensitivity of SERS as well as the molecular specificity of DNA sequence hybridization. Furthermore, these new probe s preclude the use of radioactive labels. As illustrated herein, SERGen probes have been used as primers in polymerase chain reaction (PCR) amplifications of specific DNA sequences, hence further boosting the sensitivity of the technology. We also describe several approaches to developing SERS-active DNA assay platforms, addressing the challenges of making the SERGen technology accessible and practical for clinical settings. The usefulness of the SERGen approach has been demonstrated in the detection of HIV, BRCA1 breast cancer, and BAX genes. There is great potential for the use of numerous SERGen probes for multiplexed detection of multiple biological targets.

Authors
Stokes, DL; Allain, LR; Isola, N; Vo-Dinh, T
MLA Citation
Stokes, DL, Allain, LR, Isola, N, and Vo-Dinh, T. "SERS gene probe for DNA diagnostics." Proceedings of SPIE - The International Society for Optical Engineering 4958 (2003): 98-108.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4958
Publish Date
2003
Start Page
98
End Page
108
DOI
10.1117/12.488679

Short pulse laser propagation through tissues for biomedical imaging

An experimental and numerical study is performed to analyse short pulse laser propagation through tissue phantoms with and without inhomogeneities embedded in it. Short pulse laser probing techniques have distinct advantages over conventional very large pulse width or cw lasers primarily due to the additional information conveyed about the tissue interior by the temporal variation of the observed signal. Both the scattered temporal transmitted and reflected optical signals are measured experimentally using a streak camera for samples irradiated with a short pulse laser source. Parametric study involving different scattering and absorption coefficients of tissue phantoms and inhomogeneities as well as the detector position and orientation is performed. The temporal and spatial profiles of the scattered optical signals are compared with the numerical modelling results obtained by solving the transient radiative transport equation using the discrete ordinates technique.

Authors
Das, C; Trivedi, A; Mitra, K; Vo-Dinh, T
MLA Citation
Das, C, Trivedi, A, Mitra, K, and Vo-Dinh, T. "Short pulse laser propagation through tissues for biomedical imaging." Journal of Physics D: Applied Physics 36.14 (2003): 1714-1721.
Source
scival
Published In
Journal of Physics D: Applied Physics
Volume
36
Issue
14
Publish Date
2003
Start Page
1714
End Page
1721
DOI
10.1088/0022-3727/36/14/310

Multi-functional biochip for medical diagnostics and pathogen detection

We describe a multi-functional biochip (MFB), which uses two different types of bioreceptors, including nucleic acid and antibody probes, on a single platform. The multi-functional capability of the MFB device for biomedical diagnostics is illustrated by measurements of DNA probes specific to gene fragments of Bacillus anthracis and antibody probes targeted to Escherichia coli. Calibration curves for monitoring pathogenic species using antibody probes against E. coli and DNA probes for B. anthracis illustrate the capability of the device for medical diagnostics and for quantitative detection of pathogenic agents. © 2003 Published by Elsevier Science B.V.

Authors
Vo-Dinh, T; Griffin, G; Stokes, DL; Wintenberg, A
MLA Citation
Vo-Dinh, T, Griffin, G, Stokes, DL, and Wintenberg, A. "Multi-functional biochip for medical diagnostics and pathogen detection." Sensors and Actuators, B: Chemical 90.1-3 (2003): 104-111.
Source
scival
Published In
Sensors and Actuators, B: Chemical
Volume
90
Issue
1-3
Publish Date
2003
Start Page
104
End Page
111
DOI
10.1016/S0925-4005(03)00048-0

Chapter 17 Nanosensor and nanoprobe systems for in vivo bioanalysis

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Chapter 17 Nanosensor and nanoprobe systems for in vivo bioanalysis." Comprehensive Analytical Chemistry 39 (2003): 685-700.
Source
scival
Published In
Comprehensive Analytical Chemistry
Volume
39
Publish Date
2003
Start Page
685
End Page
700
DOI
10.1016/S0166-526X(03)80122-8

Introduction

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Introduction." Proceedings of SPIE - The International Society for Optical Engineering 4958 (2003): ix-.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4958
Publish Date
2003
Start Page
ix

Critical assessment: Use of supersonic jet spectrometry for complex mixture analysis (IUPAC Technical Report)

When cooled to a temperature of a few K using supersonic jet expansion into a vacuum, a molecule exists in the lowest vibrational level of the ground electronic state and is isolated at collision-free conditions. The absorption or excitation/fluorescence spectrum is then greatly simplified, when transitions occur from this single vibrational level to a limited number of vibrational levels in the excited electronic state. This method, called supersonic jet spectrometry, is a powerful analytical technique because of its high selectivity, since the chemical species can be accurately identified and selectively quantified using the sharp spectral features even for large molecules. Supersonic jet spectrometry has distinct advantages over other low-temperature spectrometries, in that it can be combined with gas-phase separation and detection techniques such as chromatography or mass spectrometry. Therefore, this spectrometric technique can be used as a versatile analytical means, not only for basic research on pure substances, but also for practical trace analysis of chemical species in multicomponent samples (e.g., in biological monitoring or in environmental monitoring).

Authors
Imasaka, T; Moore, DS; Vo-Dinh, T
MLA Citation
Imasaka, T, Moore, DS, and Vo-Dinh, T. "Critical assessment: Use of supersonic jet spectrometry for complex mixture analysis (IUPAC Technical Report)." Pure and Applied Chemistry 75.7 (2003): 975-998.
Source
scival
Published In
Pure and applied chemistry. Chimie pure et appliquee
Volume
75
Issue
7
Publish Date
2003
Start Page
975
End Page
998

Photoacoustic method for the simultaneous acquisition of optical and ultrasonic spectra

A novel method for the simultaneous acquisition of optical absorption and ultrasonic attenuation spectra is described. The technique is based on the photoacoustic generation of bi-directional ultrasonic pulses by a thin optical absorber that is remote from the sample. A single piezoelectric transducer ultimately detects the two pulses of ultrasound, and the captured signals are used to determine both the optical absorption and ultrasonic attenuation properties of the sample. Measurements on a polycarbonate resin sample using the simultaneous photoacoustic method and conventional techniques show good agreement, indicating the validity of the method. © 2003 Acoustical Society of America.

Authors
Mobley, J; Vo-Dinh, T
MLA Citation
Mobley, J, and Vo-Dinh, T. "Photoacoustic method for the simultaneous acquisition of optical and ultrasonic spectra." Acoustic Research Letters Online 4 (2003): 89-94.
Source
scival
Published In
Acoustics research letters online : ARLO
Volume
4
Publish Date
2003
Start Page
89
End Page
94
DOI
10.1121/1.1590936

Photochemically prepared gold nanoparticles: A substrate for surface enhanced Raman scattering

Gold nanoparticles have been prepared in aqueous Triton X-100 medium using a new photochemical procedure. The characterization of the particle is made using transmission electron microscopy studies. The effects of analyte molecules such as pyridine and salt such as sodium chloride on the sol are studied. The photochemically prepared gold nanoparticles has been used successfully for surface enhanced Raman scattering studies with various types of compounds.

Authors
Pal, A; Pal, T; Stokes, DL; Vo-Dinh, T
MLA Citation
Pal, A, Pal, T, Stokes, DL, and Vo-Dinh, T. "Photochemically prepared gold nanoparticles: A substrate for surface enhanced Raman scattering." Current Science 84.10 (2003): 1342-1346.
Source
scival
Published In
Current science
Volume
84
Issue
10
Publish Date
2003
Start Page
1342
End Page
1346

A miniature biochip system for detection of aerosolized Bacillus globigii spores

The feasibility of using a novel detection scheme for the analysis of biological warfare agents is demonstrated using Bacillus globigii spores, a surrogate species for Bacillus anthracis. In this paper, a sensitive and selective enzyme-linked immunosorbent assay using a novel fluorogenic alkaline phosphatase substrate (dimethylacridinone phosphate) is combined with a compact biochip detection system, which includes a miniature diode laser for excitation. Detection of aerosolized spores was achieved by coupling the miniature system to a portable bioaerosol sampler, and the performance of the antibody-based recognition and enzyme amplification method was evaluated. The bioassay performance was found to be compatible with the air sampling device, and the enzymatic amplification was found to be an attractive amplification method for detection of low spore concentrations. The combined portable bioaerosol sampler and miniature biochip system detected 100 B. globigii spores, corresponding to 17 aerosolized spores/L of air. Moreover, the incorporation of the miniature diode laser with the self-contained biochip design allows for a compact system that is readily adaptable to field use. In addition, these studies have included investigations into the tradeoff between assay time and sensitivity.

Authors
Stratis-Cullum, DN; Griffin, GD; Mobley, J; Vass, AA; Vo-Dinh, T
MLA Citation
Stratis-Cullum, DN, Griffin, GD, Mobley, J, Vass, AA, and Vo-Dinh, T. "A miniature biochip system for detection of aerosolized Bacillus globigii spores." Analytical Chemistry 75.2 (2003): 275-280.
Source
scival
Published In
Analytical Chemistry
Volume
75
Issue
2
Publish Date
2003
Start Page
275
End Page
280
DOI
10.1021/ac026068+

Real-time monitoring of polycyclic aromatic hydrocarbons in cigarette smoke using time-resolved laser-induced fluorescence

Cigarette smoke contains a large number of chemicals and gaseous compounds including polycyclic aromatic hydrocarbons (PAHs). Due to the importance of PAHs and their health effects in cigarettes, development of systems to analyze PAHs in cigarette smoke may become useful in developing a less harmful product. However, the complexity of cigarette smoke chemistry remains a significant obstacle in its analysis: many cigarette smoke components are produced due to reactions such as decomposition and recombination of cigarette components during the smoking process. Methods to analyze these reactions in real-time are needed. In this article the authors report direct monitoring of pyrene in mainstream smoke using time-gated laser-induced fluorescence (LIF) based on fiber optics. The time-gated detection system could provide a reduced background signal of mainstream smoke when using optimized gate delay and gate width parameters. The results demonstrate the feasibility of direct monitoring of PAHs in mainstream smoke.

Authors
Song, JM; Jagannathan, R; Stokes, DL; Vo-Dinh, T; Hajaligol, MR
MLA Citation
Song, JM, Jagannathan, R, Stokes, DL, Vo-Dinh, T, and Hajaligol, MR. "Real-time monitoring of polycyclic aromatic hydrocarbons in cigarette smoke using time-resolved laser-induced fluorescence." Polycyclic Aromatic Compounds 23.4 (2003): 429-439.
Source
scival
Published In
Polycyclic Aromatic Compounds
Volume
23
Issue
4
Publish Date
2003
Start Page
429
End Page
439

Advanced biochip: Principle and applications in medical diagnostics and pathogen detection

An important factor in medical diagnostics is rapid, selective, and sensitive detection of biochemical substances (proteins, metabolites, nucleic acids), biological species or living systems (bacteria, virus or related components) at trace levels in biological samples (e.g., tissues, blood and other bodily fluids). This manuscript provides an overview of the operating principle and application of an integrated multi-functional biochip based on integrated circuit complementary metal oxide semiconductor (CMOS) sensor array for use in medical diagnostics and pathogen detection. The usefulness and potential of the biochip as a rapid diagnostic tool at the physician's office and as a practical, inexpensive screening tool for pathogens under field conditions are discussed.

Authors
Vo-Dinh, T; Griffin, GD; Wintenberg, AL; Stokes, DL; Mobley, J; Askari, M; Maples, R
MLA Citation
Vo-Dinh, T, Griffin, GD, Wintenberg, AL, Stokes, DL, Mobley, J, Askari, M, and Maples, R. "Advanced biochip: Principle and applications in medical diagnostics and pathogen detection." Proceedings - IEEE International Symposium on Circuits and Systems 3 (2003): III622-III625.
Source
scival
Published In
Proceedings - IEEE International Symposium on Circuits and Systems
Volume
3
Publish Date
2003
Start Page
III622
End Page
III625

Nanosensor for in vivo measurement of the carcinogen benzo[a]pyrene in a single cell.

This work describes the fabrication and the application of an antibody-based fiber-optic nanosensor for in situ measurements of the carcinogen benzo[a]pyrene (BaP) in a single cell. This antibody-based spectroscopic nanosensor is miniaturized enabling the detection of fluorescent analytes in single cells. In addition to measuring fluorescent analytes in single cells, the nanosensor has the potential to be applied for both diagnostic and proteomics purposes. In this work, the human breast carcinoma cell line, MCF-7, was used as the model system to perform BaP measurements in single cells. A standard concentration curve for BaP was established and used to perform quantitative analyses of BaP in individual cells. From these analyses, it was estimated that the concentration of BaP in the individual cells investigated was approximately 3.61 x 10(-10) M. The results obtained demonstrate the application of antibody-based nanosensors for performing in situ measurements inside a single cell.

Authors
Kasili, PM; Cullum, BM; Griffin, GD; Vo-Dinh, T
MLA Citation
Kasili, PM, Cullum, BM, Griffin, GD, and Vo-Dinh, T. "Nanosensor for in vivo measurement of the carcinogen benzo[a]pyrene in a single cell." J Nanosci Nanotechnol 2.6 (December 2002): 653-658.
PMID
12908430
Source
pubmed
Published In
Journal of nanoscience and nanotechnology
Volume
2
Issue
6
Publish Date
2002
Start Page
653
End Page
658

Radiation dosimetry using three-dimensional optical random access memories

The ability to determine particle type and energy plays an important role in the dosimetry of heavy charged particles (HCP) and neutrons. A new approach to radiation dosimetry is presented, which is shown to be capable of particle type and energy discrimination. This method is based on utilising radiation induced changes in the digital information stored on three-dimensional optical random access memories (3D ORAM). 3D ORAM is a small cube (a few mm3) composed of poly(methyl methacrylate) doped with a photochromic dye, and it was originally proposed as a memory device in high speed parallel computers. A Nd:YAG laser system is used to write and read binary information (bits) on the ORAM, which functions as a charged particle detector. Both the read and the write processes use two laser beams that simultaneously strike the material to cause a colour change at their intersection (similar to the darkening of light-sensitive sunglasses when exposed to sunlight.) The laser produces colour changes in the ORAM, which then reverts to the original colour ('bit-flips') at sites where energy is deposited from interaction with incident HCP or neutron-recoil protons. The feasibility of this approach was demonstrated both theoretically and experimentally. Calculations based on track structure theory (TST) predict that when HCP interact with the ORAM material, the local energy deposition is capable of inducing measurable 'bit-flips'. These predictions were recently confirmed experimentally using two types of ORAM systems, one based on spirobenzopyran and the other on anthracene, as the photochromic dyes.

Authors
Moscovitch, M; Phillips, GW; Cullum, BM; Mobley, J; Bogard, JS; Emfietzoglou, D; Vo-Dinh, T
MLA Citation
Moscovitch, M, Phillips, GW, Cullum, BM, Mobley, J, Bogard, JS, Emfietzoglou, D, and Vo-Dinh, T. "Radiation dosimetry using three-dimensional optical random access memories." Radiation Protection Dosimetry 101.1-4 (October 19, 2002): 17-22.
Source
scopus
Published In
Radiation Protection Dosimetry
Volume
101
Issue
1-4
Publish Date
2002
Start Page
17
End Page
22

Integrated CMOS microchip system with capillary array electrophoresis.

A complementary metal oxide semiconductor (CMOS)-capillary array electrophoresis (CAE) system has been used for DNA analysis. Because of its compactness and multiplex capability, the CAE-CMOS microchip is very suitable for the construction of a miniaturized high-throughput system for bioassays. Use of simultaneous laser-beam focusing on to the capillary array and a microscope objective contributed to the construction of the compact CMOS microchip-CAE system. To test the constructed system 100-base-pair (bp) DNA ladders and Hind III digest lambda DNA were separated in poly(vinylpyrrolidone) (PVP) sieving matrix. The miniaturized and integrated CMOS microchip system used in this work had great potential for combination with a variety of microfabricated devices for biomedical research.

Authors
Song Joon, M; Vo-Dinh, T
MLA Citation
Song Joon, M, and Vo-Dinh, T. "Integrated CMOS microchip system with capillary array electrophoresis." Anal Bioanal Chem 373.6 (July 2002): 399-403.
PMID
12172674
Source
pubmed
Published In
Analytical and Bioanalytical Chemistry
Volume
373
Issue
6
Publish Date
2002
Start Page
399
End Page
403
DOI
10.1007/s00216-002-1353-4

Characterization of antibodies against benzo[a]pyrene with thermodynamic and kinetic constants.

Antibodies of a polyclonal antiserum against benzo[a]pyrene were characterized by determining thermodynamic and kinetic constants of the antigen-antibody reaction. Label-free binding assays with optical detection based on reflectometric interference spectroscopy were performed to determine these constants. Different evaluation methods for kinetic measurements were compared. Also, cross-reactivity against two other polycyclic aromatic hydrocarbons, chrysene and pyrene, was checked. The affinity constant between the antibodies and benzo[a]pyrene in homogeneous phase was determined to be K=(5.3+/-0.3)x10(7) M(-1) which was in the middle of the usual range of antibody affinities. The association rate constant for the reaction at the surface was determined to be (3.8+/-0.9)x10(5) M(-1) s(-1), the dissociation rate constant as (9.7+/-0.5)x10(-3) s(-1). Different evaluation methods applied to the kinetic measurements led to the same results. This antiserum would be suitable for the selective determination of benzo[a]pyrene in concentrated samples.

Authors
Länge, K; Griffin, G; Vo-Dinh, T; Gauglitz, G
MLA Citation
Länge, K, Griffin, G, Vo-Dinh, T, and Gauglitz, G. "Characterization of antibodies against benzo[a]pyrene with thermodynamic and kinetic constants." Talanta 56.6 (April 8, 2002): 1153-1161.
PMID
18968596
Source
pubmed
Published In
Talanta
Volume
56
Issue
6
Publish Date
2002
Start Page
1153
End Page
1161

Analysis of short-pulse laser photon transport through tissues for optical tomography.

We describe a method for analyzing short-pulse laser propagation through tissues for the detection of tumors and inhomogeneities in tissues with the goal of developing a time-resolved optical tomography system. Traditional methods for analyzing photon transport in tissues usually involve the parabolic or diffusion approximation, which implies infinite speed of propagation of the optical signal. To overcome such limitations we calculate the transmitted and reflected intensity distributions, using the damped-wave hyperbolic P(1) and the discrete-ordinates methods, for a wide range of laser, tissue, and tumor parameters. The results are compared with the parabolic diffusion P(1) approximation.

Authors
Sakami, M; Mitra, K; Vo-Dinh, T
MLA Citation
Sakami, M, Mitra, K, and Vo-Dinh, T. "Analysis of short-pulse laser photon transport through tissues for optical tomography." Opt Lett 27.5 (March 1, 2002): 336-338.
PMID
18007795
Source
pubmed
Published In
Optics Letters
Volume
27
Issue
5
Publish Date
2002
Start Page
336
End Page
338

Crossed-beam two-photon readout system for three-dimensional radiation dosimeters

A two-photon readout system, that allowed for the readout of information on ionizing radiation from the three dimensional (3D) optical random access memory (ORAM) materials without polymer fracturing, was investigated. A Q-switched, frequency-doubled Nd:YAG laser was used as the two-photon excitation source. An optical attenuator was employed to adjust the intensity of the 1064 nm laser beam. It was found that the two-photon excited fluorescence of anthracene-doped 3D ORAM materials could be obtained without polymer fracturing.

Authors
Song, JM; Cullum, BM; Mobley, J; Bogard, JS; Moscovitch, M; Phillips, GW; Vo-Dinh, T
MLA Citation
Song, JM, Cullum, BM, Mobley, J, Bogard, JS, Moscovitch, M, Phillips, GW, and Vo-Dinh, T. "Crossed-beam two-photon readout system for three-dimensional radiation dosimeters." Review of Scientific Instruments 73.12 (2002): 4214-4217.
Source
scival
Published In
Review of Scientific Instruments
Volume
73
Issue
12
Publish Date
2002
Start Page
4214
End Page
4217
DOI
10.1063/1.1518789

Radiation dosimetry using three-dimensional optical random access memories

Authors
Moscovitch, M; Phillips, GW; Cullum, BM; Mobley, J; Bogard, JS; Emfietzoglou, D; Vo-Dinh, T
MLA Citation
Moscovitch, M, Phillips, GW, Cullum, BM, Mobley, J, Bogard, JS, Emfietzoglou, D, and Vo-Dinh, T. "Radiation dosimetry using three-dimensional optical random access memories." SOLID STATE DOSIMETRY, PTS 1 AND 2, PROCEEDINGS (2002): A17-A22.
Source
wos-lite
Published In
SOLID STATE DOSIMETRY, PTS 1 AND 2, PROCEEDINGS
Publish Date
2002
Start Page
A17
End Page
A22

Development of a portable Raman spectrometer for medical diagnostics

This paper describes a self-contained, portable Raman instrument that has been developed for biomedical analyses. The instrument consists of a 785-nm diode laser for excitation, an acousto-optic tunable filter (AOTF) for wavelength discrimination, and an avalanche photodiode for detection. The primary component of this system is the AOTF and it has been selected based on its spectral range along with its high resolution, ∼7.5 cm-1. Software has been developed in house in the programming language of C for controlling the instrument (i.e. the AOTF frequency, the signal acquisition, etc.). Evaluation of this instrument has been performed by analyzing several standard samples and comparing their spectra to spectra acquired using a conventional laboratory system. In addition to system evaluation, this paper will also discuss potential applications of this instrument to multiplexed genechip types of analyses.

Authors
Cullum, BM; Mobley, J; Stokes, DL; Allain, LR; Stratis, DN; Wintenberg, AL; Maples, B; Vo-Dinh, T
MLA Citation
Cullum, BM, Mobley, J, Stokes, DL, Allain, LR, Stratis, DN, Wintenberg, AL, Maples, B, and Vo-Dinh, T. "Development of a portable Raman spectrometer for medical diagnostics." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): 82-90.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
82
End Page
90
DOI
10.1117/12.466637

In vivo fluorescence spectroscopy for diagnosis of skin cancer

Laser-induced fluorescence spectroscopy at the excitation of 410 nm and using the fluorescence intensity as a marker was used as an in vivo technique for detection of squamous cell carcinoma, basal cell carcinoma and precancerous lesions. The technique worked best in patients with skin type I (93% (4/45) of the spectra from cancers classified correctly as cancer).

Authors
Panjehpour, M; Julius, C; Phan, MN; Vo-Dinh, T; Overholt, S
MLA Citation
Panjehpour, M, Julius, C, Phan, MN, Vo-Dinh, T, and Overholt, S. "In vivo fluorescence spectroscopy for diagnosis of skin cancer." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): 20-31.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
20
End Page
31
DOI
10.1117/12.466652

Novel modeling techniques for tumor diagnostics using pulsed laser sources

In this paper, a two-dimensional transient radiation transport algorithm is developed to analyze short pulse laser transport through a tissue medium having tumors and inhomogeneities imbedded in it. Short pulse probing techniques have distinct advantages over conventional very large pulse width or cw lasers primarily due to the additional information conveyed about the tissue interior by the temporal variation of the observed signal. The distinct feature is the multiple scattering induced temporal signatures that persists for time periods greater than the duration of the source pulse and is a function of the source pulse width, the scattering/absorbing properties and nature of the medium, the location in the medium where the properties undergo changes. A wide range of parameters such as tissue and tumor size, scattering/absorbing properties and phase function of tissues and tumors, tumor location, laser beam diameter will affect the temporal and spatial distribution of the reflected and transmitted optical signals. The goal is to perform a parametric study in order to gain insight about laser-tissue interaction characteristics with the goal to detect tumors.

Authors
Sakami, M; Mitra, K; Vo-Dinh, T
MLA Citation
Sakami, M, Mitra, K, and Vo-Dinh, T. "Novel modeling techniques for tumor diagnostics using pulsed laser sources." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): 155-164.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
155
End Page
164
DOI
10.1117/12.466643

Transcranial ultrasound for brain injury monitoring: Initial clinical studies

In this work, we discuss data acquired in a clinical investigation to evaluate the utility of transcranial ultrasound for monitoring/detecting brain injury. Using a portable ultrasonic data acquisition system, over one thousand transcranial waveforms were captured from five subjects, including three head-injured patients. Several representative waveforms are shown to demonstrate the feasibility of the ultrasonic detection scheme and to illustrate the similarities and variabilities among the signals acquired in this study.

Authors
Mobley, J; Cullum, BM; Holland, MC; Vo-Dinh, T
MLA Citation
Mobley, J, Cullum, BM, Holland, MC, and Vo-Dinh, T. "Transcranial ultrasound for brain injury monitoring: Initial clinical studies." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): 53-60.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
53
End Page
60
DOI
10.1117/12.466635

Multi-spectral imaging for medical diagnostics

We report the development of a multi-spectral imaging (MSI) device for medical diagnostic applications. The MSI device uses an acousto-optic tunable filter (AOTF) for wavelength selection and a two-dimensional charge-coupled device (CCD) for detection. Unlike a tunable grating or prism-based monochromator, the tunable filter has no moving parts, and can be rapidly tuned to any wavelength within its operating range. The large aperture of the AOTF and its high spatial resolution allows the optical image from an imaging fiber optic probe (IFP) to be recorded by the CCD. These characteristics, combined with their small size, make AOTFs important new alternatives to conventional monochromators, especially for spectral imaging in biomedical applications. Several applications of biomedical interest (fluorescence imaging, brain tissue imaging, etc.) are described to illustrate the usefulness of the MSI system.

Authors
Vo-Dinh, T; Kasili, P; Cullum, B
MLA Citation
Vo-Dinh, T, Kasili, P, and Cullum, B. "Multi-spectral imaging for medical diagnostics." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): 13-19.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
13
End Page
19
DOI
10.1117/12.466651

Opto-ultrasonic system for generation of ultrasound and optical detection

In this work, we examine a system that exploits the photoacoustic effect to act as an ultrasonic pulse generator and an optical detector. At the core of the system are a solid substrate and an optical absorber. To test the performance as an ultrasonic generator, several substrate-absorber (SA) combinations are examined. The pulses generated by these systems are evaluated based on their bi-directional symmetry and characteristics of their Fourier spectra. To demonstrate the use of the SA system as an optical detector, a linearity study was performed for one specific choice of substrate and absorber. These substrate-absorber systems exhibit a variety of behaviors, and form a versatile set of tools for ultrasound, optical and hybrid use.

Authors
Mobley, J; Vo-Dinh, T
MLA Citation
Mobley, J, and Vo-Dinh, T. "Opto-ultrasonic system for generation of ultrasound and optical detection." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): 173-179.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
173
End Page
179
DOI
10.1117/12.466645

Investigation of Lysozyme-Chitobioside Interactions Using Synchronous Luminescence and Lifetime Measurements

Beside their ability to disrupt the outer membranes of some microorganisms, lysozymes also experience interactions with chitins or their fluorescent analogs. It has been well established that chitins bind to the cleft of lysozymes and the subsites of the location of the different N-acetylglucos- amines that are parts of chitins have been identified. Moreover, it has been well documented that a 1,4-β-bond must be located between subsite D and subsite E to be cleaved. Nevertheless, a better understanding of the biophysical and biochemical processes is needed. In this paper, pulsed fluorescence was used to further investigate the mechanism by which the binding of fluorescent analogs of chitin (4-methylumbelliferyl chitobiose and 4-methylumbelliferyl chitotriose) to hen egg-white lysozyme results in an increase of their fluorescence intensity. Although such an increase is not observed when these chitobiosides bind to turkey egg-white lysozyme, synchronous fluorescence techniques show that this binding induces a quenching of the native fluorescence of both these proteins. The findings of this study, associated with previously published cyrstallographic data allow us to suggest that the system lysozyme-chitobioside partitions in two three-dimensional conformational states: an enzymatic active conformation and a storage conformation. These states are separated by an energy barrier, with the storage conformation being more populated than the enzymatic active conformation below 45°C.

Authors
Viallet, PM; Vo-Dinh, T; Vigo, J; Salmon, J-M
MLA Citation
Viallet, PM, Vo-Dinh, T, Vigo, J, and Salmon, J-M. "Investigation of Lysozyme-Chitobioside Interactions Using Synchronous Luminescence and Lifetime Measurements." Journal of Fluorescence 12.1 (2002): 57-63.
Source
scival
Published In
Journal of Fluorescence
Volume
12
Issue
1
Publish Date
2002
Start Page
57
End Page
63
DOI
10.1023/A:1015311203428

Proceedings of SPIE: Biomedical Diagnostic, Guidance, and Surgical-Assist Systems IV: Introduction

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Proceedings of SPIE: Biomedical Diagnostic, Guidance, and Surgical-Assist Systems IV: Introduction." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): ix-.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
ix

Proceedings of SPIE - The International Society for Optical Engineering: Introduction

Authors
Tuchin, VV; Izatt, JA; Fujimoto, JG
MLA Citation
Tuchin, VV, Izatt, JA, and Fujimoto, JG. "Proceedings of SPIE - The International Society for Optical Engineering: Introduction." Proceedings of SPIE - The International Society for Optical Engineering 4619 (2002): xi-xii.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4619
Publish Date
2002
Start Page
xi
End Page
xii

Nanosensors: Design and application to site-specific cellular analyses

We report the development and application of an antibody-based nanoprobe for in situ measurements within a single cell. The nanoprobe has an antibody-based probe targeted to benzopyrene tetrol (BPT), a metabolite of the carcinogen benzo[a]pyrene (BaP) and the BaP-DNA adduct. Detection of BPT is of biomedical interest since this species can potentially serve as a biomarker for the monitoring of DNA damage due to BaP exposure and for possible pre-cancer diagnoses. The measurements were performed on the rat liver epithelial Clone 9 cell line, which was used as the model cell system. Nanoprobes were inserted into individual cells, incubated five minutes to allow antigen-antibody binding, and then removed for fluorescence detection. Prior to measurements, the cells had been treated with BPT. A concentration of 9.6 ± 0.2 × 10-11 M has been determined for BPT in the individual cells investigated. The results demonstrate the possibility of in situ measurements inside a single cell using an antibody-based nanoprobes.

Authors
Cullum, BM; Griffin, GD; Vo-Dinh, T
MLA Citation
Cullum, BM, Griffin, GD, and Vo-Dinh, T. "Nanosensors: Design and application to site-specific cellular analyses." Proceedings of SPIE - The International Society for Optical Engineering 4615 (2002): 148-154.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4615
Publish Date
2002
Start Page
148
End Page
154
DOI
10.1117/12.466642

Surface-enhanced Raman scattering detection of the breast cancer susceptibility gene BRCA1 using a silver-coated microarray platform

Surface-enhanced Raman scattering (SERS) spectroscopy was used to monitor DNA hybridization of a fragment of the BRCA1 breast cancer susceptibility gene on modified silver surfaces. Rhodamine B was covalently attached to a 5′-amino-labeled oligonucleotide sequence (23 mer) through a succinimidyl ester intermediate in methanol. The silver surfaces were prepared by depositing a discontinuous layer (9.0nm) of silver onto glass slides, which had been etched with HF to form a microwell platform, and subsequently modified with a monolayer of mercaptoundecanoic acid. The complementary probe was covalently attached to the silver surfaces using a succinimidyl ester intermediate in acetonitrile. The silver island substrate allows a very large enhancement of the Raman signal of the DNA-Rhodamine B, and clear distinction between hybridized samples and controls on a microwell array sampling platform. © 2002 Elsevier Science B.V. All rights reserved.

Authors
Allain, LR; Vo-Dinh, T
MLA Citation
Allain, LR, and Vo-Dinh, T. "Surface-enhanced Raman scattering detection of the breast cancer susceptibility gene BRCA1 using a silver-coated microarray platform." Analytica Chimica Acta 469.1 (2002): 149-154.
Source
scival
Published In
Analytica Chimica Acta
Volume
469
Issue
1
Publish Date
2002
Start Page
149
End Page
154
DOI
10.1016/S0003-2670(01)01537-9

Integrated circuit microchip system with multiplex capillary electrophoresis module for DNA analysis

In this paper, we describe the use of an integrated circuit (IC) microchip system as a detector in multiplex capillary electrophoresis (CE). This combination of multiplex capillary gel electrophoresis and the IC microchip technology represents a novel approach to DNA analysis on the microchip platform. Separation of DNA ladders using a multiplex CE microsystem of four capillaries was monitored simultaneously using the IC microchip system. The IC microchip-CE system has advantages such as low cost, rapid analysis, compactness, and multiplex capability, and has great potential as an alternative system to conventional capillary array gel electrophoresis systems based on charge-coupled device (CCD) detection. © 2002 Elsevier Science B.V. All rights reserved.

Authors
Song, JM; Mobley, J; Vo-Dinh, T
MLA Citation
Song, JM, Mobley, J, and Vo-Dinh, T. "Integrated circuit microchip system with multiplex capillary electrophoresis module for DNA analysis." Analytica Chimica Acta 466.2 (2002): 187-192.
Source
scival
Published In
Analytica Chimica Acta
Volume
466
Issue
2
Publish Date
2002
Start Page
187
End Page
192
DOI
10.1016/S0003-2670(02)00552-4

Simultaneous detection of the tumor suppressor FHIT gene and protein using the multi-functional biochip.

The tumor suppressor gene, fragile histidine triad (FHIT), encompasses the most common human chromosomal fragile site, at 3pl4.2. Detection of FHIT gene is important in cancer diagnostics since its alterations have been associated with several human cancers. A unique multi-functional biochip for simultaneous detection of FHIT DNA and FHIT protein on the same platform was applied. The design of the biochip is based on miniaturization of photodiodes, where functioning of multiple optical sensing elements, amplifiers, discriminators, and logic circuitry are integrated on a single IC board. Performance of biochip is based on biomolecular recognition processes using both DNA and protein bioreceptors, Cy5-labeled probes and laser excitation. Application of biochip for concurrent detection of various immobilized target DNA and protein molecules and multiplex of DNA and protein on the same microarray was accomplished. Linearity of biochip for quantitative measurements was demonstrated. Results demonstrated utility of this multi-functional biochip as a useful detection technology with applications in biological and clinical laboratories.

Authors
Askari, MDF; Miller, GH; Vo-Dinh, T
MLA Citation
Askari, MDF, Miller, GH, and Vo-Dinh, T. "Simultaneous detection of the tumor suppressor FHIT gene and protein using the multi-functional biochip." Cancer Detect Prev 26.5 (2002): 331-342.
PMID
12518863
Source
pubmed
Published In
Cancer Detection and Prevention
Volume
26
Issue
5
Publish Date
2002
Start Page
331
End Page
342

Nanobiosensors: probing the sanctuary of individual living cells.

Recently, nanotechnology has been revolutionizing important areas in molecular biology, especially diagnostics and therapy at the molecular and cellular level. The combination of nanotechnology, biology, and photonics opens the possibility of detecting and manipulating atoms and molecules using nanodevices, which have the potential for a wide variety of medical uses at the cellular level. The nanoprobes were fabricated with optical fibers pulled down to tips with distal ends having sizes of approximately 30-50 nm. The nanoscale size of this new class of sensors, allows for measurements in the smallest of environments. One such environment that has evoked a great deal of interest is that of individual cells. Using these nanobiosensors, it has become possible to probe individual chemical species in specific locations throughout a cell. This article provides an overview of the principle, development, and applications of optical nanosensor systems for in vivo bioanalysis at the single-cell level. The fiberoptics nanoprobes were covalently bound with antibodies that are selective to target analyte molecules. Excitation light is launched into the fiber and the resulting evanescent field at the tip of the fiber is used to excite target molecules bound to the antibody molecules. The fluorescence emission from the analyte molecules is then collected via a microscope. The usefulness and potential of this nanotechnology-based biosensor systems in biological research and applications in single-cell analysis are discussed.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Nanobiosensors: probing the sanctuary of individual living cells." J Cell Biochem Suppl 39 (2002): 154-161. (Review)
PMID
12552615
Source
pubmed
Published In
Journal of cellular biochemistry. Supplement
Volume
39
Publish Date
2002
Start Page
154
End Page
161
DOI
10.1002/jcb.10427

Nanosensor for In Vivo Measurement of the Carcinogen Benzo[a]pyrene in a Single Cell

This work describes the fabrication and the application of an antibody-based fiber-optic nanosensor for in situ measurements of the carcinogen benzo[a]pyrene (BaP) in a single cell. This antibody-based spectroscopic nanosensor is miniaturized enabling the detection of fluorescent analytes in single cells. In addition to measuring fluorescent analytes in single cells, the nanosensor has the potential to be applied for both diagnostic and proteomics purposes. In this work, the human breast carcinoma cell line, MCF-7, was used as the model system to perform BaP measurements in single cells. A standard concentration curve for BaP was established and used to perform quantitative analyses of BaP in individual cells. From these analyses, it was estimated that the concentration of BaP in the individual cells investigated was ∼3.61 × 10 -10 M. The results obtained demonstrate the application of antibody-based nanosensors for performing in situ measurements inside a single cell.

Authors
Kasili, PM; Cullum, BM; Griffin, GD; Vo-Dinh, T
MLA Citation
Kasili, PM, Cullum, BM, Griffin, GD, and Vo-Dinh, T. "Nanosensor for In Vivo Measurement of the Carcinogen Benzo[a]pyrene in a Single Cell." Journal of Nanoscience and Nanotechnology 2.6 (2002): 653-658.
Source
scival
Published In
Journal of nanoscience and nanotechnology
Volume
2
Issue
6
Publish Date
2002
Start Page
653
End Page
658
DOI
10.1166/153348802321105941

Laser-induced fluorescence spectroscopy for in vivo diagnosis of non-melanoma skin cancers.

BACKGROUND AND OBJECTIVES: Laser-induced fluorescence spectroscopy is a non-invasive technique previously used for detection of cancer in a variety of organ systems. The objective of this study was to determine whether in vivo laser-induced fluorescence spectroscopy alone at the visible excitation wavelength of 410 nm could be used to detect non-melanoma skin cancers. STUDY DESIGN/MATERIALS AND METHODS: The system consisted of a nitrogen/dye laser tuned at 410 nm, an optical multichannel analyzer, and a fiber optic probe for excitation of tissue and collection of fluorescence emission. Two hundred and seventy nine measurements were performed from normal and abnormal tissues in 49 patients. Patients were classified as having either skin types I, II, or III. Biopsy of the abnormal tissues were then performed. Each measurement was assigned as either normal, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), pre-cancerous, or benign. Total emission photon count was used as the discriminating index. A threshold value was calculated to separate normal tissue indices from indices of cancer tissues. The classification accuracy of each data point was determined using the threshold value. RESULTS: Cancers were classified 93, 89, and 78% correctly in patients with skin types I, II, and III, respectively. Normal tissues were classified 93, 88, and 50% correctly in patients with skin types I, II, and III, respectively. Using the same threshold, pre-cancerous spectra were classified 78 and 100% correctly in skin types I and III, respectively. Benign lesions were classified 100, 46, and 27% correctly in patient with skin types I, II, and III, respectively. CONCLUSIONS: In vivo laser induced fluorescence spectroscopy at 410 nm excitation and using the intensity of emission signal is effective for detection of BCC, SCC, and actinic keratosis, specially in patients with light colored skin.

Authors
Panjehpour, M; Julius, CE; Phan, MN; Vo-Dinh, T; Overholt, S
MLA Citation
Panjehpour, M, Julius, CE, Phan, MN, Vo-Dinh, T, and Overholt, S. "Laser-induced fluorescence spectroscopy for in vivo diagnosis of non-melanoma skin cancers." Lasers Surg Med 31.5 (2002): 367-373.
PMID
12430156
Source
pubmed
Published In
Lasers in Surgery and Medicine
Volume
31
Issue
5
Publish Date
2002
Start Page
367
End Page
373
DOI
10.1002/lsm.10125

Radiation dosimetry using three-dimensional optical random access memories.

The ability to determine particle type and energy plays an important role in the dosimetry of heavy charged particles (HCP) and neutrons. A new approach to radiation dosimetry is presented, which is shown to be capable of particle type and energy discrimination. This method is based on utilising radiation induced changes in the digital information stored on three-dimensional optical random access memories (3D ORAM). 3D ORAM is a small cube (a few mm3) composed of poly(methyl methacrylate) doped with a photochromic dye. and it was originally proposed as a memory device in high speed parallel computers. A Nd:YAG laser system is used to write and read binary information (bits) on the ORAM, which functions as a charged particle detector. Both the read and the write processes use two laser beams that simultaneously strike the material to cause a colour change at their intersection (similar to the darkening of light-sensitive sunglasses when exposed to sunlight.) The laser produces colour changes in the ORAM, which then reverts to the original colour ('bit-flips') at sites where energy is deposited from interaction with incident HCP or neutron-recoil protons. The feasibility of this approach was demonstrated both theoretically and experimentally. Calculations based on track structure theory (TST) predict that when HCP interact with the ORAM material, the local energy deposition is capable of inducing measurable 'bit-flips'. These predictions were recently confirmed experimentally using two types of ORAM systems, one based on spirobenzopyran and the other on anthracene, as the photochromic dyes.

Authors
Moscovitch, M; Phillips, GW; Cullum, BM; Mobley, J; Bogard, JS; Emfietzoglou, D; Vo-Dinh, T
MLA Citation
Moscovitch, M, Phillips, GW, Cullum, BM, Mobley, J, Bogard, JS, Emfietzoglou, D, and Vo-Dinh, T. "Radiation dosimetry using three-dimensional optical random access memories." Radiat Prot Dosimetry 101.1-4 (2002): 17-22.
PMID
12382699
Source
pubmed
Published In
Radiation Protection Dosimetry
Volume
101
Issue
1-4
Publish Date
2002
Start Page
17
End Page
22

Cancer gene detection using surface-enhanced Raman scattering (SERS)

We describe the development of a surface-enhanced Raman scattering (SERS) method for cancer gene detection. The technology uses DNA gene probes based on SERS labels for gene detection. The detection method uses nanostructured metallic substrates as SERS-active platforms. The surface-enhanced Raman gene (SERGen) probes can be used to detect DNA targets via hybridization to DNA sequences complementary to these probes. The probes do not require the use of radioactive labels and have great potential to provide both sensitivity and selectivity. The usefulness of the SERGen approach and its applications in cancer gene diagnostics (e.g. BRCA1 breast cancer gene and BAX gene) is discussed. Copyright © 2002 John Wiley & Sons, Ltd.

Authors
Vo-Dinh, T; Allain, LR; Stokes, DL
MLA Citation
Vo-Dinh, T, Allain, LR, and Stokes, DL. "Cancer gene detection using surface-enhanced Raman scattering (SERS)." Journal of Raman Spectroscopy 33.7 (2002): 511-516.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
33
Issue
7
Publish Date
2002
Start Page
511
End Page
516
DOI
10.1002/jrs.883

Microarray sampling-platform fabrication using bubble-jet technology for a biochip system.

The fabrication of microarrays containing PCR-amplified genomic DNA extracts from mice tumors on a Zetaprobe membrane using a modified thermal ink-jet printer is described. A simple and cost-effective procedure for the fabrication of microarrays containing biological samples using a modified bubble-jet printing system is presented. Because of their mass-produced design, ink-jet printers are a much cheaper alternative to conventional spotting techniques. The usefulness of the biochip microarray platform is illustrated by the detection of human fragile histidine triad (FHIT), a tumor suppressor gene. Subcutaneous carcinomas were induced with MKN/FHIT and MKN/E4 cell lines in immunodeficient mice. Several weeks into their development, the tumors from both groups of mice were removed and subjected to DNA extraction by lysis of tissue samples. The extracted DNA samples were amplified by PCR (30 cycles) using the primers corresponding to nucleotides 2 to 18 of the FHIT sequence. The resulting solution was transferred to the individual reservoirs of a three-color cartridge from a conventional thermal ink-jet printer (HP 694C), and arrays were printed on to a Zetaprobe membrane. After spotting, these membranes were used in a hybridization assay, using fluorescent probes, and detected with a biochip.

Authors
Allain, LR; Askari, M; Stokes, DL; Vo-Dinh, T
MLA Citation
Allain, LR, Askari, M, Stokes, DL, and Vo-Dinh, T. "Microarray sampling-platform fabrication using bubble-jet technology for a biochip system." Fresenius J Anal Chem 371.2 (September 2001): 146-150.
PMID
11678184
Source
pubmed
Published In
Fresenius' journal of analytical chemistry
Volume
371
Issue
2
Publish Date
2001
Start Page
146
End Page
150

Laser-induced fluorescence studies of polycyclic aromatic hydrocarbons (PAH) vapors at high temperatures.

In this work, we present the fluorescence spectra of anthracene and pyrene vapors at different elevated temperatures (from 150 to 650 degrees C) excited with the 337 nm line of a nitrogen laser. We describe the high temperature effects on the resulting spectral properties including spectral intensity, spectral bandwidth and spectral shift. We found that the PAH fluorescence spectral bandwidths become very broad as the temperature increases. The broadening is mainly due to thermal vibrational sequence congestion. We also have found that the fluorescence intensity of pyrene vapor increases with increasing temperature, which results from the increase of the pyrene vapor absorption cross section at 337 nm.

Authors
Chi, Z; Cullum, BM; Stokes, DL; Mobley, J; Miller, GH; Hajaligol, MR; Vo-Dinh, T
MLA Citation
Chi, Z, Cullum, BM, Stokes, DL, Mobley, J, Miller, GH, Hajaligol, MR, and Vo-Dinh, T. "Laser-induced fluorescence studies of polycyclic aromatic hydrocarbons (PAH) vapors at high temperatures." Spectrochim Acta A Mol Biomol Spectrosc 57.7 (June 2001): 1377-1384.
PMID
11446693
Source
pubmed
Published In
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Volume
57
Issue
7
Publish Date
2001
Start Page
1377
End Page
1384

Application of an antibody biochip for p53 detection and cancer diagnosis.

Detection of the p53 tumor suppressor gene is important in early cancer diagnostics because alterations in the gene have been associated with carcinogenic manifestations in several tissue types in humans. We have developed an antibody-based detection instrument, the biochip, to detect the presence of the anti-p53 antibody in human serum. The design of this highly integrated detector system is based on miniaturized phototransistors having multiple optical sensing elements, amplifiers, discriminators, and logic circuitry on an IC board. The system utilizes laser excitation and fluorescence signals to detect complex formation between the p53 monoclonal antibody and the p53 antigen. Recognition antibodies are immobilized on a nylon membrane platform and incubated in solutions containing antigens labeled with Cy5, a fluorescent cyanine dye. Subsequently, this membrane is placed on the detection platform of the biochip and fluorescence signal is induced using a 632.8-nm He-Ne laser. Using this immuno-biochip, we have been able to detect binding of the p53 monoclonal antibody to the human p53 cancer protein in biological matrices. The performance of the integrated phototransistors and amplifier circuits of the biochip, previously evaluated through measurement of the signal output response for various concentrations of fluorescein-labeled molecules, have illustrated the linearity of the microchip necessary for quantitative analysis. The design of this biochip permits sensitive, selective and direct measurements of a variety of antigen-antibody formations at very low concentrations. Furthermore, the acquisitions of the qualitative and quantitative results are accomplished rapidly, in about 15 min. These features demonstrate the potential of this antibody-based biochip for simple, rapid and early biomedical diagnostics of cancer.

Authors
Askari, M; Alarie, JP; Moreno-Bondi, M; Vo-Dinh, T
MLA Citation
Askari, M, Alarie, JP, Moreno-Bondi, M, and Vo-Dinh, T. "Application of an antibody biochip for p53 detection and cancer diagnosis." Biotechnol Prog 17.3 (May 2001): 543-552.
PMID
11386877
Source
pubmed
Published In
Biotechnology Progress
Volume
17
Issue
3
Publish Date
2001
Start Page
543
End Page
552
DOI
10.1021/bp010008s

Detection of E. coli using a microfluidics-based antibody biochip detection system

This work demonstrates the detection of E. coli using a 2-dimensional photosensor array biochip which is efficiently equipped with a microfluidics sample/reagent delivery system for on-chip monitoring of bioassays. The biochip features a 4 × 4 array of independently operating photodiodes that are integrated along with amplifiers, discriminators and logic circuitry on a single platform. The microfluidics system includes a single 0.4 mL reaction chamber which houses a sampling platform that selectively captures detection probes from a sample through the use of immobilized bioreceptors. The independently operating photodiodes allow simultaneous monitoring of multiple samples. In this study the sampling platform is a cellulosic membrane that is exposed to E. coli organisms and subsequently analyzed using a sandwich immunoassay involving a Cy5-labeled antibody probe. The combined effectiveness of the integrated circuit (IC) biochip and the immunoassay is evaluated for assays performed both by conventional laboratory means followed by detection with the IC biochip, and through the use of the microfluidics system for on-chip detection. Highlights of the studies show that the biochip has a linear dynamic range of three orders of magnitude observed for conventional assays, and can detect 20 E. coli organisms. Selective detection of E. coli in a complex medium, milk diluent, is also reported for both off-chip and on-chip assays.

Authors
Stokes, DL; Griffin, GD; Vo-Dinh, T
MLA Citation
Stokes, DL, Griffin, GD, and Vo-Dinh, T. "Detection of E. coli using a microfluidics-based antibody biochip detection system." Fresenius' Journal of Analytical Chemistry 369.1 (March 20, 2001): 295-301.
Source
scopus
Published In
Fresenius' journal of analytical chemistry
Volume
369
Issue
1
Publish Date
2001
Start Page
295
End Page
301

Proceedings of SPIE - The International Society for Optical Engineering: Introduction

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Proceedings of SPIE - The International Society for Optical Engineering: Introduction." January 1, 2001.
Source
scopus
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4254
Publish Date
2001

Vapor detection of polyaromatic compounds using laser-induced fluorescence

In this work, we present the fluorescence spectra of anthracene and pyrene vapors at different elevated temperatures (from 150 to 650°C) excited with the 337 nm line of a nitrogen laser. We describe the high temperature effects on the resulting spectral properties including spectral intensity, spectral bandwidth and spectral shift. We found that the PAH fluorescence spectral bandwidths become very broad as the temperature increases. The broadening is mainly due to thermal vibrational sequence congestion. We also have found that the fluorescence intensity of pyrene vapor increases with increasing temperature, which results from the increase of the pyrene vapor absorption cross section at 337 nm.

Authors
Chi, Z; Cullum, BM; Mobley, J; Miller, GH; Vo-Dinh, T
MLA Citation
Chi, Z, Cullum, BM, Mobley, J, Miller, GH, and Vo-Dinh, T. "Vapor detection of polyaromatic compounds using laser-induced fluorescence." Proceedings of SPIE - The International Society for Optical Engineering 4199 (2001): 173-179.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4199
Publish Date
2001
Start Page
173
End Page
179
DOI
10.1117/12.417374

Laser-induced fluorescence spectroscopy for skin cancer diagnostics

Objective: The goal of this pilot study was to determine whether in vivo laser-induced fluorescence intensity may be used to distinguish normal skin from malignant lesions. Materials and Methods: The system consisted of a nitrogen/dye laser tuned at 410 nm, an optical multichannel analyzer, and a fiber optic probe designed for excitation of tissue and collection of fluorescence emission. The intensity of fluorescence at the wavelength of 500 nm (I500) was used as the discriminating index. All data were normalized with respect to fluorescence of a standard dye. A total of 117 measurements were performed from normal and abnormal tissues in 28 patients. Patients were classified as having either of skin types I, II or III. Following the measurement, a biopsy of the abnormal tissue was performed. Using the biopsy results, each measurement was assigned under one of the following categories: basal cell carcinoma, squamous cell carcinoma, precancerous lesions, and benign lesions. Results: In patients with skin type I, the I500 index for basal cell carcinoma, squamous cell carcinoma and precancerous lesions were significantly different than that of normal tissue. There was no significant difference between I500 of benign lesions and normal tissue. In patients with skin type II, the I500 for basal cell carcinoma and squamous cell carcinoma was significantly different than that of normal tissues. Benign tissue could not be distinguished from normal tissue. In patients with skin type III, basal cell carcinoma and precancerous lesion could be easily distinguished from normal tissues. However, there was a statistically significant difference between benign and normal tissue. Conclusion: This pilot study indicated that the laser-induced fluorescence intensity of skin may be used to distinguish normal from cancerous and precancerous tissue.

Authors
Panjehpour, M; Julius, C; Overholt, S; Phan, M; Vo-Dinh, T
MLA Citation
Panjehpour, M, Julius, C, Overholt, S, Phan, M, and Vo-Dinh, T. "Laser-induced fluorescence spectroscopy for skin cancer diagnostics." Proceedings of SPIE - The International Society for Optical Engineering 4254 (2001): 136-143.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4254
Publish Date
2001
Start Page
136
End Page
143
DOI
10.1117/12.427954

Ultrasonic scattering and transmission properties of mammalian white matter in the detection of brain injury

In this work, we examine the orientation-dependent scattering and attenuation properties of white matter from mammalian brain tissue. We find that both the backscatter and attenuation of ultrasound in these tissues exhibit anisotropy. Furthermore, when extrapolated down to 1 MHz, it appears that the attenuation differences will be small but the backscatter differences are potentially resolvable. From a tissue characterization context, this means that the impact of changes due to the rotation of overlying tissues will be small compared to the changes in the strength of the backscatter signals from the regions of interest.

Authors
Mobley, J; Mathur, AN; Vo-Dinh, T
MLA Citation
Mobley, J, Mathur, AN, and Vo-Dinh, T. "Ultrasonic scattering and transmission properties of mammalian white matter in the detection of brain injury." Proceedings of SPIE - The International Society for Optical Engineering 4254 (2001): 7-14.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4254
Publish Date
2001
Start Page
7
End Page
14
DOI
10.1117/12.427939

Field-portable AOTF-based monitor technology for environmental sensing

The development of a field-portable Raman instrument for environmental analyses is described. It is based on the use of a near-infrared frequency-stabilized diode laser for excitation, an acousto-optic tunable filter for wavelength selection, and an avalanche photodiode for detection. Evaluation of this instrument for the monitoring of environmentally important species will be discussed as well as its ability to be operated in room light without significantly increasing the background signal. In addition, we will also describe a baseline removal procedure based on second derivative approach that simplifies and increases the accuracy of the instrument's automated identification algorithm.

Authors
Cullum, BM; Mobley, J; Wintenberg, AL; Maples, RA; Stokes, DL; Vo-Dinh, T
MLA Citation
Cullum, BM, Mobley, J, Wintenberg, AL, Maples, RA, Stokes, DL, and Vo-Dinh, T. "Field-portable AOTF-based monitor technology for environmental sensing." Proceedings of SPIE - The International Society for Optical Engineering 4576 (2001): 244-254.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4576
Publish Date
2001
Start Page
244
End Page
254
DOI
10.1117/12.456965

Ultrasonic diffraction in the design of photoacoustic probes

In this work, we examine the role of diffraction in the design of ring-shaped ultrasonic receivers for photoacoustic probes. The sensitivity patterns of ultrasonic receiving rings are calculated at 1 MHz using the angular spectrum technique. Three separate series of simulations are considered: flat ring with a fixed outer diameter and a variable inner diameter, flat ring with a fixed inner diameter and variable outer diameter, and a spherically focused ring with a variable inner diameter. From these results the focal zone characteristic and sensitivities are calculated. For the planar rings, we find that the spatial sensitivity varies markedly with ring width but the overall sensitivities are comparable. For the focused (spherically curved) rings, the focal distances and beam volumes were similar while the sensitivity grew with ring thickness.

Authors
Mobley, J; Cullum, BM; Vo-Dinh, T
MLA Citation
Mobley, J, Cullum, BM, and Vo-Dinh, T. "Ultrasonic diffraction in the design of photoacoustic probes." Proceedings of SPIE - The International Society for Optical Engineering 4254 (2001): 151-163.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4254
Publish Date
2001
Start Page
151
End Page
163
DOI
10.1117/12.427956

High-temperature vapor detection of polycyclic aromatic hydrocarbon fluorescence

Polycyclic aromatic hydrocarbons (PAHs) are generated from the incomplete combustion of organic matters in a wide variety of natural and man-made materials, such as fuels. It is important to develop an analytical technique for rapidly monitoring PAH generation at high temperatures during pyrolysis processes. This work describes a real-time and in situ technique using laser-induced fluorescence to detect PAH vapors at elevated temperatures. We report fluorescence spectra of several typical PAH model compounds, such as pyrene, phenanthrene and chrysene. We have also examined the temperature effects on PAH fluorescence spectra such as spectral shift, intensity and band width. © 2001 Elsevier Science Ltd. All rights reserved.

Authors
Chi, Z; Cullum, BM; Stokes, DL; Mobley, J; Miller, GH; Hajaligol, MR; Vo-Dinh, T
MLA Citation
Chi, Z, Cullum, BM, Stokes, DL, Mobley, J, Miller, GH, Hajaligol, MR, and Vo-Dinh, T. "High-temperature vapor detection of polycyclic aromatic hydrocarbon fluorescence." Fuel 80.12 (2001): 1819-1824.
Source
scival
Published In
Fuel
Volume
80
Issue
12
Publish Date
2001
Start Page
1819
End Page
1824
DOI
10.1016/S0016-2361(01)00065-5

Detection of neutrons using a novel three-dimensional optical random access memory technology (3D-ORAM)

We report for the first time, the development of a three-dimensional optical random access memory (3D-ORAM) material for neutron dosimetry. Detection of energetic neutrons is important in many applications, spanning from radioactive waste monitoring to space exploration. These anthracene-based photochromic dosimeters show a decrease in fluorescence intensity following exposure to energetic neutrons. Unlike current neutron dosimeters, where foreknowledge of the neutron energy is necessary to determine an exposure dose, these materials can be used in unknown environments (e.g. space exploration). A readout system has also been developed to determine the radiation characteristics (e.g. neutron energy) necessary for estimating dose. The results presented in this work, demonstrate the potential of these novel materials for space exploration and other applications where foreknowledge of neutron energy is unknown and current dosimeters are incapable of providing accurate dose information.

Authors
Cullum, BM; Mobley, J; Bogard, JS; Moscovitch, M; Phillips, GW; Vo-Dinh, T
MLA Citation
Cullum, BM, Mobley, J, Bogard, JS, Moscovitch, M, Phillips, GW, and Vo-Dinh, T. "Detection of neutrons using a novel three-dimensional optical random access memory technology (3D-ORAM)." Proceedings of SPIE - The International Society for Optical Engineering 4199 (2001): 165-172.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4199
Publish Date
2001
Start Page
165
End Page
172
DOI
10.1117/12.417372

Field-portable AOTF-based monitor technology for environmental sensing

The development of a field-portable Raman instrument for environmental analyses is described. It is based on the use of a near-infrared frequency-stabilized diode laser for excitation, an acousto-optic tunable filter for wavelength selection, and an avalanche photodiode for detection. Evaluation of this instrument for the monitoring of environmentally important species will be discussed as well as its ability to be operated in room light without significantly increasing the background signal. In addition, we will also describe a baseline removal procedure based on second derivative approach that simplifies and increases the accuracy of the instrument's automated identification algorithm.

Authors
Cullum, BM; Mobley, J; Wintenberg, AL; Maples, RA; Stokes, DL; Vo-Dinh, T
MLA Citation
Cullum, BM, Mobley, J, Wintenberg, AL, Maples, RA, Stokes, DL, and Vo-Dinh, T. "Field-portable AOTF-based monitor technology for environmental sensing." Proceedings of SPIE - The International Society for Optical Engineering 4577 (2001): 65-75.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4577
Publish Date
2001
Start Page
65
End Page
75
DOI
10.1117/12.455723

Use of short-pulse laser for optical tomography of tissues

This paper analyzes the short pulse laser propagation through tissues for development of a time-resolved optical tomography system for detection of tumors and inhomogeneities in tissues. Traditional method for analyzing optical transport in tissues is the parabolic or diffusion approximation in which the energy flux is assumed proportional to the fluence (intensity averaged over all solid angles) gradients. The inherent drawback in this model is that it predicts infinite speed of propagation of the optical signal. In this paper accurate hyperbolic or wave nature of transient radiative transfer formulation is used to overcome such drawbacks. The transmitted and reflected intensity distributions are obtained using hyperbolic P1 and discrete ordinates method and the results are compared with the parabolic diffusion P1 approximation. Parametric study of tissue thickness, pulse width, scattering and absorption coefficients of tissues, tumor location, size and properties, and scattering phase function distribution is also performed to analyze their effect on the transmitted and reflected optical signals.

Authors
Mitra, K; Vo-Dinh, T
MLA Citation
Mitra, K, and Vo-Dinh, T. "Use of short-pulse laser for optical tomography of tissues." Proceedings of SPIE - The International Society for Optical Engineering 4254 (2001): 61-71.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4254
Publish Date
2001
Start Page
61
End Page
71
DOI
10.1117/12.427953

Nanosensors and biochips: Frontiers in biomolecular diagnostics

In the past two decades, the biotechnology and medical fields have seen great advances in the development of novel technologies that open new horizons for identifying and quantifying biomolecules, and diagnosing diseases. This manuscript provides an overview of two of those important technologies, nanosensors and biochips. We describe various types of nanosensors and biochips that have been developed for biological and medical applications, along with significant advances achieved over the last several years in these technologies. Some applications of nanosensors, developed in our laboratory for single-cell analysis, and applications of biochips for biological sensing of pathogenic agents and medical diagnostics are described to illustrate the usefulness and potential of these technologies. © 2001 Elsevier Science B.V.

Authors
Vo-Dinh, T; Cullum, BM; Stokes, DL
MLA Citation
Vo-Dinh, T, Cullum, BM, and Stokes, DL. "Nanosensors and biochips: Frontiers in biomolecular diagnostics." Sensors and Actuators, B: Chemical 74.1-3 (2001): 2-11.
Source
scival
Published In
Sensors and Actuators B: Chemical
Volume
74
Issue
1-3
Publish Date
2001
Start Page
2
End Page
11
DOI
10.1016/S0925-4005(00)00705-X

Nanosensors for the analysis of a single cell

Submicron fiber-optic biosensors have been developed and used to measure toxic chemicals within single cells. These sensors are fabricated by pulling the distal-end of an optical fiber to a diameter of less than one micron and coating them with antibodies to selectively bind the species of interest. This paper describes the use of these fibers to selectively measure the concentration of benzo[a]pyrene tetrol, a metabolite of benzo[a]pyrene, within individual cells of two different cell lines, human mammary carcinoma cells and rat liver epithelial cells. The results from these measurements have been used to evaluate the analytical figures of merit of these sensors such as detection limits, which were found to be 0.64 ± 0.17 × 10-11 M for BPT. In addition, measurements were performed both extracellularly and intracellularly, and an increase in variation of approximately 4% was determined for the intacellular measurements, relative to the extracellular measurements.

Authors
Cullum, BM; Griffin, GD; Vo-Dinh, T
MLA Citation
Cullum, BM, Griffin, GD, and Vo-Dinh, T. "Nanosensors for the analysis of a single cell." Proceedings of SPIE - The International Society for Optical Engineering 4254 (2001): 35-40.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4254
Publish Date
2001
Start Page
35
End Page
40
DOI
10.1117/12.427943

Nanosensors for biochemical analysis of single cells

In the past couple of decades, new techniques in chemical and biological sensing have provided information and technology that have greatly enhanced the field of biological research. In this area of sensing, one of the most recent technological advances has been in the area of nanometer-sized sensors, called nanosensors. These nanosensors have been reported in the literature over the past decade, and have been based upon many different types of measurements (i.e. optical, electrochemical, etc.). This article reviews the field of nanosensors, with particular emphasis on optical-based sensors and their application to the measurement of chemical species inside individual cells.

Authors
Cullum, BM; Vo-Dinh, T
MLA Citation
Cullum, BM, and Vo-Dinh, T. "Nanosensors for biochemical analysis of single cells." Chimica Oggi 19.1-2 (2001): 58-62.
Source
scival
Published In
Chimica Oggi
Volume
19
Issue
1-2
Publish Date
2001
Start Page
58
End Page
62

Proceedings of SPIE - The International Society for Optical Engineering: Introduction

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Proceedings of SPIE - The International Society for Optical Engineering: Introduction." Proceedings of SPIE - The International Society for Optical Engineering 4254 (2001): ix-.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
4254
Publish Date
2001
Start Page
ix

Synchronous luminescence: A simple technique for the analysis of hydrolysis activity of the fragile histidine triad protein

Human fragile histidine triad (FHIT) protein has dinucleoside 5′,5‴-P1,Pn-polyphosphates hydrolysis activity, with AMP being one of the reaction products. Application of synchronous luminescence (SL) spectroscopy, in which both excitation and emission wavelengths are scanned simultaneously while a constant wavelength interval is maintained between them, was investigated for detection of the enzymatic activity of the FHIT protein. Ability of SL to identify reaction components, AMP production and its increase as a result of increase in substrate concentration and inhibition of the hydrolysis activity by ZnCl2 are demonstrated.

Authors
Askari, M; Miller, G; Vo-Dinh, T
MLA Citation
Askari, M, Miller, G, and Vo-Dinh, T. "Synchronous luminescence: A simple technique for the analysis of hydrolysis activity of the fragile histidine triad protein." Biotechnology Letters 23.20 (2001): 1697-1702.
Source
scival
Published In
Biotechnology Letters
Volume
23
Issue
20
Publish Date
2001
Start Page
1697
End Page
1702
DOI
10.1023/A:1012404430463

Introduction

Authors
Valente, AM; Kay, J; Califf, RM; Sanders, SP
MLA Citation
Valente, AM, Kay, J, Califf, RM, and Sanders, SP. "Introduction." American Heart Journal 142.2 (2001): 218-223.
Source
scival
Published In
American Heart Journal
Volume
142
Issue
2
Publish Date
2001
Start Page
218
End Page
223
DOI
10.1067/mhj.2001.117064

Micro arrays and biochips: Applications and potential in genomics and proteomics

This report provides an overview of the development and applications of DNA-based microarrays and biochip technology in genomics. DNA microarrays and biochip technologies are having a significant impact on a wide variety of areas in genomic research. Many fields, including gene discovery, drug discovery, toxicological research, and medical diagnostics, will benefit from the use of DNA micro array and biochip technologies. High-density micro array chips with relatively large detection systems are useful in the research laboratory for monitoring the expression of large numbers of genes in parallel. On the other hand, small and inexpensive integrated biochips that combine probe arrays with sensor microchips are most suitable for medical diagnosis at the site-of-care.

Authors
Vo-Dinh, T; Askari, M
MLA Citation
Vo-Dinh, T, and Askari, M. "Micro arrays and biochips: Applications and potential in genomics and proteomics." Current Genomics 2.4 (2001): 399-415.
Source
scival
Published In
Current genomics
Volume
2
Issue
4
Publish Date
2001
Start Page
399
End Page
415
DOI
10.2174/1389202013350724

Biomedical implications of protein folding and misfolding

A review of protein-folding mechanisms is presented to indicate (i) the formation of correctly folded and misfolded forms, and (ii) the biomedical implications involved. Protein mechanisms may be classified into series and series-parallel mechanisms. The mechanism may involve one or more stable intermediate (partially folded, misfolded, with some structure) states. It is the parallel or the 'off-pathway' step(s) that lead to the aggregate (misfolded state). This aggregate state yields the amyloid deposits in human tissue that lead to diseases in humans that are resistant to treatment. Means by which the off-pathway step may be minimized and the correct folding pathway enhanced are presented. Particular emphasis is placed on the in vivo machinery (chaperones) that is in place in the cells, and how it functions to allow the proteins to fold in the correct and active form, thus minimizing the amyloid deposits in tissues. More effort needs to be placed to understand the function of these chaperones, and thus help facilitate the formation of active and stable proteins in the cells. Though more effort needs to be placed in the present treatment strategies, novel treatment procedures also need to be explored in order to develop effective strategies to treat these seemingly intractable diseases.

Authors
Sadana, A; Vo-Dinh, T
MLA Citation
Sadana, A, and Vo-Dinh, T. "Biomedical implications of protein folding and misfolding." Biotechnology and Applied Biochemistry 33.1 (2001): 7-16.
Source
scival
Published In
Biotechnology and Applied Biochemistry
Volume
33
Issue
1
Publish Date
2001
Start Page
7
End Page
16
DOI
10.1042/BA20000044

A kinetic analysis using fractals of cellular analyte-receptor binding and dissociation

A fractal analysis is presented for cellular analyte-receptor binding and dissociation kinetics using a biosensor. Data taken from the literature may be modelled, in the case of binding, using a single-fractal analysis or a dual-fractal analysis. The dual-fractal analysis represents a change in the binding mechanism as the reaction progresses on the surface. The predictive relationship developed for the equilibrium constant, K (affinity which is equal to kd/k1 or 2), as a function of the analyte concentration is of particular value since it provides a means by which the affinity may be manipulated. This should be of assistance in cell-surface reactions, drug-candidate optimization and for the design of immunodiagnostic devices. Relationships are also presented for the binding and dissociation rate coefficients as a function of their corresponding fractal dimension, Df or the degree of heterogeneity that exists on the surface, and the analyte concentration in solution. When analyte-receptor binding or dissociation is involved, an increase in the heterogeneity on the surface (increase in Df or Dfd as the case may be) leads to an increase in the binding and the dissociation rate coefficients. It is suggested that an increase in the degree of heterogeneity on the surface leads to an increase in the turbulence on the surface owing to the irregularities on the surface. This turbulence promotes mixing, minimizes diffusional limitations and leads subsequently to an increase in the binding and the dissociation rate coefficients. The binding and dissociation rate coefficients are rather sensitive to the degree of heterogeneity, Df and Dfd, respectively, that exists on the biosensor surface. The heterogeneity on the surface in general affects the binding and dissociation rate coefficients differently. In general, the analyte concentration in solution has a mild affect on the fractal dimension for binding or the fractal dimension for dissociation. This is indicated by the low values of the exponent in the predictive relationships developed.

Authors
Sadana, A; Vo-Dinh, T
MLA Citation
Sadana, A, and Vo-Dinh, T. "A kinetic analysis using fractals of cellular analyte-receptor binding and dissociation." Biotechnology and Applied Biochemistry 33.1 (2001): 17-28.
Source
scival
Published In
Biotechnology and Applied Biochemistry
Volume
33
Issue
1
Publish Date
2001
Start Page
17
End Page
28
DOI
10.1042/BA20000048

Detection of E. coli using a microfluidics-based antibody biochip detection system

This work demonstrates the detection of E. coli using a 2-dimensional photosensor array biochip which is efficiently equipped with a microfluidics sample/reagent delivery system for on-chip monitoring of bioassays. The biochip features a 4 × 4 array of independently operating photodiodes that are integrated along with amplifiers, discriminators and logic circuitry on a single platform. The microfluidics system includes a single 0.4 mL reaction chamber which houses a sampling platform that selectively captures detection probes from a sample through the use of immobilized bioreceptors. The independently operating photodiodes allow simultaneous monitoring of multiple samples. In this study the sampling platform is a cellulosic membrane that is exposed to E. coli organisms and subsequently analyzed using a sandwich immunoassay involving a Cy5-labeled antibody probe. The combined effectiveness of the integrated circuit (IC) biochip and the immunoassay is evaluated for assays performed both by conventional laboratory means followed by detection with the IC biochip, and through the use of the microfluidics system for on-chip detection. Highlights of the studies show that the biochip has a linear dynamic range of three orders of magnitude observed for conventional assays, and can detect 20 E. coli organisms. Selective detection of E. coli in a complex medium, milk diluent, is also reported for both off-chip and on-chip assays.

Authors
Stokes, DL; Griffin, GD; Vo-Dinh, T
MLA Citation
Stokes, DL, Griffin, GD, and Vo-Dinh, T. "Detection of E. coli using a microfluidics-based antibody biochip detection system." Fresenius' Journal of Analytical Chemistry 369.1 (2001): 295-301.
Source
scival
Published In
Fresenius' journal of analytical chemistry
Volume
369
Issue
1
Publish Date
2001
Start Page
295
End Page
301

Three-dimensional optical random access memory materials for use as radiation dosimeters.

This article describes the development of the first three-dimensional optical random access memory (3D-ORAM) material and readout system for monitoring energetic neutrons. Two different photochromic dyes, 5'-chloro-6-nitro-1',3',3'-trimethylspiro-[2H-1-benzopyran-2,2'-in doline] (spirobenzopyran) and anthracene, have been investigated for use in these 3-D ORAM dosimeter materials. These dyes were immobilized in a poly(methyl methacrylate) support, and the resulting dosimeter materials were irradiated with neutrons from a Cf-252 source. Fluorescence measurements from the dosimeter show a dramatic decrease in the overall fluorescence intensity of the 3D-ORAM dosimeter exposed to the Cf-252, relative to a nonirradiated dosimeter. In addition, a two-photon excitation readout system has been developed for determining characteristics of the radiation that are necessary for estimating dose.

Authors
Cullum, BM; Mobley, J; Bogard, JS; Moscovitch, M; Phillips, GW; Vo-Dinh, T
MLA Citation
Cullum, BM, Mobley, J, Bogard, JS, Moscovitch, M, Phillips, GW, and Vo-Dinh, T. "Three-dimensional optical random access memory materials for use as radiation dosimeters." Anal Chem 72.22 (November 15, 2000): 5612-5617.
PMID
11101239
Source
pubmed
Published In
Analytical Chemistry
Volume
72
Issue
22
Publish Date
2000
Start Page
5612
End Page
5617

The development of optical nanosensors for biological measurements.

This article discusses and documents the basic concepts of, and developments in, the field of optical nanosensors and nanobiosensors. It describes the progression of this field of research from its birth up to the present, with emphasis on the techniques of sensor construction and their application to biological systems. After a brief overview of the techniques for fabricating nanometer-sized optical fibers, we describe the various types of transducer and bioreceptor molecule presently used for nanosensor and nanobiosensor fabrication.

Authors
Cullum, BM; Vo-Dinh, T
MLA Citation
Cullum, BM, and Vo-Dinh, T. "The development of optical nanosensors for biological measurements." Trends Biotechnol 18.9 (September 2000): 388-393. (Review)
PMID
10942963
Source
pubmed
Published In
Trends in Biotechnology
Volume
18
Issue
9
Publish Date
2000
Start Page
388
End Page
393

Native fluorescence and mag-indo-1-protein interaction as tools for probing unfolding and refolding sequences of the bovine serum albumin subdomain in the presence of guanidine hydrochloride.

Changes in the fluorescence spectrum of tryptophans Trp 134 and Trp 212 in bovine serum albumin (BSA) and of Trp 214 of human serum albumin in the presence of the chaotropic agent guanidine hydrochloride (Gnd) were studied. A detailed analysis of the fluorescence spectrum of native BSA yielded the fluorescence spectrum for each tryptophan of BSA. Modifications in the binding of Mag-indo-1 to BSA, which results in a specific quenching of the fluorescence spectrum of Trp 134 associated with an energy transfer from Trp 134 to the protein-bound Mag-indo-1, were also investigated. Changes occurring when the Gnd concentration is decreased stepwise cover a larger concentration scale of Gnd than the reverse protocol, allowing one to suggest that the resulting conformational changes in the subdomain IA of BSA involve at least three different steps.

Authors
Viallet, PM; Vo-Dinh, T; Ribou, AC; Vigo, J; Salmon, JM
MLA Citation
Viallet, PM, Vo-Dinh, T, Ribou, AC, Vigo, J, and Salmon, JM. "Native fluorescence and mag-indo-1-protein interaction as tools for probing unfolding and refolding sequences of the bovine serum albumin subdomain in the presence of guanidine hydrochloride." J Protein Chem 19.6 (August 2000): 431-439.
PMID
11195967
Source
pubmed
Published In
Journal of protein chemistry
Volume
19
Issue
6
Publish Date
2000
Start Page
431
End Page
439

Antibody-based biosensor for breast cancer with ultrasonic regeneration.

We describe a novel method and instrumental setup for regenerating antibodies immobilized on a fiberoptic probe of an immunosensor using ultrasonic irradiation with broadband imaging transducers. The instrumental setup and irradiation conditions for antibody regeneration using ultrasound are described. The results of the measurements with antibody against breast cancer antigen illustrate the effectiveness and potential of the regenerable immunosensor. A 65% removal of the antigens bound to the Mab immobilized on the fiber surface is attained after ultrasound regeneration.

Authors
Moreno-Bondi, MC; Mobley, J; Alarie, JP; Vo-Dinh, T
MLA Citation
Moreno-Bondi, MC, Mobley, J, Alarie, JP, and Vo-Dinh, T. "Antibody-based biosensor for breast cancer with ultrasonic regeneration." J Biomed Opt 5.3 (July 2000): 350-354.
PMID
10958622
Source
pubmed
Published In
Journal of Biomedical Optics
Volume
5
Issue
3
Publish Date
2000
Start Page
350
End Page
354
DOI
10.1117/1.430006

Antibody-based nanoprobe for measurement of a fluorescent analyte in a single cell.

We report here the application of an antibody-based nanoprobe for in situ measurements of a single cell. The nanoprobe employs antibody-based receptors targeted to a fluorescent analyte, benzopyrene tetrol (BPT), a metabolite of the carcinogen benzo[a]pyrene (BaP) and of the BaP-DNA adduct. Detection of BPT is of great biomedical interest, since this species can serve as a biomarker for monitoring DNA damage due to BaP exposure and for possible precancer diagnosis. The measurements were performed on the rat liver epithelial clone 9 cell line, which was used as the model cell system. Before making measurements, the cells were treated with BPT. Nanoprobes were inserted into individual cells, incubated 5 min to allow antigen-antibody binding, and then removed for fluorescence detection. We determined a concentration of 9.6+/-0.2x10(-11) M for BPT in the individual cells investigated. The results demonstrate the possibility of in situ measurements inside a single cell using an antibody-based nanoprobe.

Authors
Vo-Dinh, T; Alarie, JP; Cullum, BM; Griffin, GD
MLA Citation
Vo-Dinh, T, Alarie, JP, Cullum, BM, and Griffin, GD. "Antibody-based nanoprobe for measurement of a fluorescent analyte in a single cell." Nat Biotechnol 18.7 (July 2000): 764-767.
PMID
10888846
Source
pubmed
Published In
Nature Biotechnology
Volume
18
Issue
7
Publish Date
2000
Start Page
764
End Page
767
DOI
10.1038/77337

Biosensors and biochips: advances in biological and medical diagnostics.

In the past two decades, the biological and medical fields have seen great advances in the development of biosensors and biochips capable of characterizing and quantifying biomolecules. This review is meant to provide an overview of the various types of biosensors and biochips that have been developed for biological and medical applications, along with significant advances over the last several years in these technologies. It also attempts to describe various classification schemes that can be used for categorizing the different biosensors and provide relevant examples of these classification schemes from recent literature.

Authors
Vo-Dinh, T; Cullum, B
MLA Citation
Vo-Dinh, T, and Cullum, B. "Biosensors and biochips: advances in biological and medical diagnostics." Fresenius J Anal Chem 366.6-7 (March 2000): 540-551. (Review)
PMID
11225766
Source
pubmed
Published In
Fresenius' journal of analytical chemistry
Volume
366
Issue
6-7
Publish Date
2000
Start Page
540
End Page
551

Intracellular measurements in mammary carcinoma cells using fiber-optic nanosensors.

Submicrometer fiber-optic biosensors have been developed and used to measure toxic chemicals within single cells. Optical fibers that have been pulled to a distal-end diameter of less than 1 micrometer are coated with antibodies to selectively bind the species of interest. This paper describes the use of these fibers to selectively measure the concentration of benzo[a]pyrene tetrol (BPT), a metabolite of benzo[a]pyrene, within individual cells of two different cell lines, human mammary carcinoma cells and rat liver epithelial cells. The results from these measurements have been used to determine the sensitivity, reproducibility, and usefulness of these nanosensors. The detection limit of these biosensors has been determined to be 0.64 +/- 0.17 x 10(-11) M for BPT.

Authors
Cullum, BM; Griffin, GD; Miller, GH; Vo-Dinh, T
MLA Citation
Cullum, BM, Griffin, GD, Miller, GH, and Vo-Dinh, T. "Intracellular measurements in mammary carcinoma cells using fiber-optic nanosensors." Anal Biochem 277.1 (January 1, 2000): 25-32.
PMID
10610686
Source
pubmed
Published In
Analytical Biochemistry
Volume
277
Issue
1
Publish Date
2000
Start Page
25
End Page
32
DOI
10.1006/abio.1999.4341

Bio-imaging system using an acousto-optic tunable filter

The interaction of light with tissue has been used to recognize disease since the mid-1800s. The recent developments of light sources, detectors, and fiber optic probes provide opportunities to measure these interactions, which yield information for tissue diagnosis at the biochemical, structural, or (patho) physiological level. In this paper, we describe a bioimaging system designed for biomedical applications and show laser-induced fluorescence (LIF) images mammalian brain tissue. The LIF imaging of tissue was carried out in vitro using two laser excitations: 488 nm and 514 nm (argon-ion laser. Images were recorded through an acousto-optic tunable filter over the range 500 nm-650 nm with a charged coupled device (CCD) camera. Background subtracted images were generated across the fluorescent wavelength. Subtraction allowed a safe comparison to be made with well-contrasted images. Of the two tested excitation wavelengths, 488 nm excitation gave the more distinctive contrast.

Authors
Kasili, P; Mobley, J; Cullum, B; Vo-Dinh, T
MLA Citation
Kasili, P, Mobley, J, Cullum, B, and Vo-Dinh, T. "Bio-imaging system using an acousto-optic tunable filter." Proceedings of SPIE - The International Society for Optical Engineering 3911 (2000): 345-354.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3911
Publish Date
2000
Start Page
345
End Page
354

Principle of synchronous luminescence (SL) technique for biomedical diagnostics

In the present study, the principle of synchronous luminescence (SL) is described for use in biomedical diagnostics. The SL method involves scanning simultaneously both emission and excitation wavelengths while keeping a constant wavelength interval between them. This SF procedure simplifies the emission spectrum and provides for greater selectivity and is used to detect subtle differences in the fluorescence emission of the biochemical species of cells and tissues. The SL method can be use to analyze tissue in vivo or to investigate spectral differences in normal and neoplastic cells in vitro. SL scans of skin tissues illustrate the use of the method. For in vitro diagnosis, a difference between the fluorescent spectra of the normal rat liver epithelial (RLE) and hepatoma cell lines were detected using synchronous fluorescence. The potential use of SF as a screening tool for cancer diagnosis is discussed.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Principle of synchronous luminescence (SL) technique for biomedical diagnostics." Proceedings of SPIE - The International Society for Optical Engineering 3911 (2000): 42-49.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3911
Publish Date
2000
Start Page
42
End Page
49

Development of an integrated single-fiber SERS sensor

An integrated fiberoptic surface-enhanced Raman scattering (SERS) sensor based on a single-fiber system is described and evaluated for remote and in situ measurements. The heart of the sensor consists of a unique single optical fiber designed to induce the SERS effect through the incorporation of alumina nanoparticles and silver coatings onto the probe tip. The unique design based on single-fiber for excitation/emission (SFEE) is practical for the fabrication of in situ sensors in microenvironments. Since the single fiber carries both the laser excitation and SERS signal radiation, optical parameters of the remote tip are simple and consistent. Depending on the tip size, the fiberoptic SERS sensor allows in situ measurements at microscale environments. Details of sensor tip fabrication and optical system design are described. Two detection schemes can be used: a `dip-and-dry' mode of detection and an in situ sensing mode are demonstrated for several compounds, including cresyl fast violet (CFV), brilliant cresyl blue (BCB), p-aminobenzoic acid (PABA) and 3-aminopyrene (3AP). To illustrate the effectiveness of this new SERS sensor for remote in situ analysis, SERS spectra of aqueous dye samples (CFV and BCB) are presented. A quantitative calibration curve for CFV in groundwater is established and a limit of optical detection of approximately 50 ppb CFV in groundwater is determined.

Authors
Stokes, DL; Vo-Dinh, T
MLA Citation
Stokes, DL, and Vo-Dinh, T. "Development of an integrated single-fiber SERS sensor." Sensors and Actuators, B: Chemical 69.1 (2000): 28-36.
Source
scival
Published In
Sensors and Actuators, B: Chemical
Volume
69
Issue
1
Publish Date
2000
Start Page
28
End Page
36
DOI
10.1016/S0925-4005(00)00291-4

Method for the simultaneous acquisition of optical absorption and sonic attenuation with photoacoustic ultrasound

In this work, we present a novel method for the simultaneous acquisition of ultrasonic attenuation and optical absorption using photoacoustically-generated ultrasound. We discuss the theory behind the technique and apply the method to measurements in mammalian tissue samples. We show that the frequency dependence of ultrasonic attenuation measured with this technique is consistent with conventionally determined values and thus holds promise for future work.

Authors
Mobley, J; Cullum, B; Vo-Dinh, T
MLA Citation
Mobley, J, Cullum, B, and Vo-Dinh, T. "Method for the simultaneous acquisition of optical absorption and sonic attenuation with photoacoustic ultrasound." Proceedings of SPIE - The International Society for Optical Engineering 3911 (2000): 180-190.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3911
Publish Date
2000
Start Page
180
End Page
190

Surface-enhanced Raman of dopamine and neurotransmitters using sol-gel substrates and polymer-coated fiber-optic probes

Surface-enhanced Raman spectroscopy (SERS) is used to detect catecholamines - viz., dopamine, norepinephrine, epinine, and isoproterenol - using a new substrate prepared with sol-gel technology. Catecholamines are complexed at the surface by iron(III) ions, which were introduced during the reduction of the silver ions embedded inside the sol-gel matrix. With the use of a He-Ne laser at a power of only 12 mW, it is possible to measure dopamine in the micromolar concentration range. A single-fiber SERS probe system was also introduced that has great potential for sampling in micro-environment applications such as in vivo measurements of dopamine. In this microprobe design both excitation and SERS signals are transmitted through the same fiber simultaneously. The tips of tapered fibers were coated with a polyvinyl alcohol polymer doped with metallic silver particles. The potential of the SERS method and microprobes for medical diagnostics is discussed.

Authors
Volkan, M; Stokes, DL; Vo-Dinh, T
MLA Citation
Volkan, M, Stokes, DL, and Vo-Dinh, T. "Surface-enhanced Raman of dopamine and neurotransmitters using sol-gel substrates and polymer-coated fiber-optic probes." Applied Spectroscopy 54.12 (2000): 1842-1848.
Source
scival
Published In
Applied Spectroscopy
Volume
54
Issue
12
Publish Date
2000
Start Page
1842
End Page
1848
DOI
10.1366/0003702001948952

Development of nanosensors and bioprobes

We describe the development and application of nanosensors having bioreceptor probes for bioanalysis. The nanoprobes were fabricated with optical fibers pulled down to tips having distal end sizes of approximately 30-60 nm. The use of two different types of receptors was investigated. Fiberoptic nanoprobes were covalently bound either with bioreceptors, such as antibodies, or with other receptors, such as cyclodextrins that are selective for the size and chemical structure of the analyte molecules. Theoretical calculations were performed to model the binding of beta-cyclodextrin with pyrene and 5,6-benzoquinoline, and to illustrate the possibility of comparing experimental data with theoretical data. The antibody-based nanoprobe was used for in situ measurements of benzopyrene tetrol in single cells. The performance of the nanosensor is illustrated by intracellular measurements performed on a rat liver epithelial cell line (Clone 9) used as the model cell system. The usefulness and potential of these nanotechnology-based biosensors in biological research and applications are discussed.

Authors
Vo-Dinh, T; Griffin, GD; Alarie, JP; Cullum, B; Sumpter, B; Noid, D
MLA Citation
Vo-Dinh, T, Griffin, GD, Alarie, JP, Cullum, B, Sumpter, B, and Noid, D. "Development of nanosensors and bioprobes." Journal of Nanoparticle Research 2.1 (2000): 17-27.
Source
scival
Published In
Journal of Nanoparticle Research
Volume
2
Issue
1
Publish Date
2000
Start Page
17
End Page
27

ASSTC and field sensors: new technology for emergency care

The US Army Medical Research and Material Command together with the US Marine Corps Combat Development Command sponsored the design and production of a far-forward, lightweight, small footprint, reconfigurable, highly mobile Advanced Surgical Suite for Trauma Casualties (ASSTC) to reduce combat casualties and morbidity. The KIA fraction has remained relatively constant over major wars and conflicts since the early 1900s. One third of the KIA perish after 10 minutes. ASSTC has the potential to dramatically lower this fraction by providing resuscitative care within a short period of wound infliction and not requiring long transport times to the caregivers. ASSTC is also unique in its capability to serve in multiple missions including humanitarian aid, infectious disease control, and disaster relief. Adding field sensor to ASSTC greatly enhances the capability of this highly mobile system to operate in many areas

Authors
Morrison, GW; Vo Dinh, T
MLA Citation
Morrison, GW, and Vo Dinh, T. "ASSTC and field sensors: new technology for emergency care." Proc. SPIE - Int. Soc. Opt. Eng. (USA) 3911 (2000): 237-243. (Academic Article)
Source
manual
Published In
Proc. SPIE - Int. Soc. Opt. Eng. (USA)
Volume
3911
Publish Date
2000
Start Page
237
End Page
243
DOI
10.1117/12.384908

Development of a compact, handheld Raman instrument with no moving parts for use in field analysis

This article describes a lightweight, self-contained, field portable Raman instrument that has been developed for rapid on-site determination of primary mixture components. The instrument consists of a helium neon (HeNe) laser for excitation, an acousto-optic tunable filter (AOTF) for wavelength discrimination, and an avalanche photodiode for detection. The AOTF is the primary component of this system and has been selected based on its spectral range (600-900 nm) along with its high resolution, ∼7.5 cm-1. Labview™ based software for controlling the AOTF frequency and the signal acquisition has also been developed. Several different samples were analyzed (both solids and liquids) using this instrument for the evaluation of parameters such as spectral resolution, sensitivity, and data acquisition speed for certain environmentally important compounds. The results from these measurements are compared with those using a conventional laboratory Raman system consisting of a grating-based spectrograph and a charge-coupled device. © 2000 American Institute of Physics.

Authors
Cullum, BM; Mobley, J; Chi, Z; Stokes, DL; Miller, GH; Vo-Dinh, T
MLA Citation
Cullum, BM, Mobley, J, Chi, Z, Stokes, DL, Miller, GH, and Vo-Dinh, T. "Development of a compact, handheld Raman instrument with no moving parts for use in field analysis." Review of Scientific Instruments 71.4 (2000): 1602-1607.
Source
scival
Published In
Review of Scientific Instruments
Volume
71
Issue
4
Publish Date
2000
Start Page
1602
End Page
1607

Instrumentation and measurement issues for nanometer particles: Workshop summary

Authors
Pui, DYH; Brock, JR; Chen, D-R; Fissan, H; Frisbie, CD; Lyman, CE; Miller, JC; Mulholland, GW; Pecora, R; Preining, O; Vo-Dinh, T
MLA Citation
Pui, DYH, Brock, JR, Chen, D-R, Fissan, H, Frisbie, CD, Lyman, CE, Miller, JC, Mulholland, GW, Pecora, R, Preining, O, and Vo-Dinh, T. "Instrumentation and measurement issues for nanometer particles: Workshop summary." Journal of Nanoparticle Research 2.1 (2000): 103-112.
Source
scival
Published In
Journal of Nanoparticle Research
Volume
2
Issue
1
Publish Date
2000
Start Page
103
End Page
112

High-temperature fluorescence measurements and instrumentation for polyaromatic hydrocarbons (PAH): A review

This paper provides an overview of high-temperature measurements of polyaromatic hydrocarbons (PAHs) and an assessment of the state-of the art methods and instrumentation that are used for those measurements. This review deals specifically with the fluorescence technique and related measurement methods. The primary emphasis of this review will be placed on the effect of high temperatures on the structural, and photophysical characteristics of PAHs and their resulting effects on the fluorescence spectra of these compounds. Specific examples of these effects and the analytical instrumentation developed and used for these measurements will be discussed and illustrated, as well as the various environments in which these measurements are performed.

Authors
Cullum, BM; Chi, Z; Vo-Dinh, T
MLA Citation
Cullum, BM, Chi, Z, and Vo-Dinh, T. "High-temperature fluorescence measurements and instrumentation for polyaromatic hydrocarbons (PAH): A review." Polycyclic Aromatic Compounds 18.1 (2000): 25-47.
Source
scival
Published In
Polycyclic Aromatic Compounds
Volume
18
Issue
1
Publish Date
2000
Start Page
25
End Page
47

Native fluorescence and Mag-indo-1-protein interaction as tools for probing unfolding and refolding sequences of the bovine serum albumin subdomain in the presence of guanidine hydrochloride

Changes in the fluorescence spectrum of tryptophans Trp 134 and Trp 212 in bovine serum albumin (BSA) and of Trp 214 of human serum albumin in the presence of the chaotropic agent guanidine hydrochloride (Gnd) were studied. A detailed analysis of the fluorescence spectrum of native BSA yielded the fluorescence spectrum for each tryptophan of BSA. Modifications in the binding of Mag-indo-1 to BSA, which results in a specific quenching of the fluorescence spectrum of Trp 134 associated with an energy transfer from Trp 134 to the protein-bound Mag-indo-1, were also investigated. Changes occurring when the Gnd concentration is decreased stepwise cover a larger concentration scale of Gnd than the reverse protocol, allowing one to suggest that the resulting conformational changes in the subdomain IA of BSA involve at least three different steps.

Authors
Viallet, PM; Vo-Dinh, T; Ribou, A-C; Vigo, J; Salmon, J-M
MLA Citation
Viallet, PM, Vo-Dinh, T, Ribou, A-C, Vigo, J, and Salmon, J-M. "Native fluorescence and Mag-indo-1-protein interaction as tools for probing unfolding and refolding sequences of the bovine serum albumin subdomain in the presence of guanidine hydrochloride." Journal of Protein Chemistry 19.6 (2000): 431-439.
Source
scival
Published In
Journal of protein chemistry
Volume
19
Issue
6
Publish Date
2000
Start Page
431
End Page
439
DOI
10.1023/A:1026589012724

Optical nanosensors and biological measurements

Authors
Cullum, PBM; Vo-Dinh, T
MLA Citation
Cullum, PBM, and Vo-Dinh, T. "Optical nanosensors and biological measurements." Biofutur 205 SUPPL. 127 (2000): 1-6.
Source
scival
Published In
Biofutur
Issue
205 SUPPL. 127
Publish Date
2000
Start Page
1
End Page
6

Laser-induced fluorescence studies of polyaromatic hydrocarbons (PAH) vapors at high temperatures

A study on how temperature changes affect the fluorescence properties of PAH, such as fluorescence intensity, bandwidth, etc., was carried out using an instrumental system. Light from a nitrogen laser, 337 nm, was utilized to excite anthracene and pyrene. The fluorescence spectra at gas-phase anthracene and pyrene were measured at various temperatures using different carrying gases (argon or nitrogen). Fluorescence bandwidths of vapor pyrene and anthracene became very broad with increasing sample temperature, which was ascribed to thermal vibrational sequence congestion and other linewidth broadening effect, such as Doppler effects. The fluorescence intensity of pyrene increased with increasing sample temperature, which was attributed to the increase of pyrene absorption cross-section at 337 nm. The results of fluorescence measurements of gas-phase PAH for the first time are important to many applications of fluorescence studies of PAH in combustion diagnostics and environmental monitoring. Original is an abstract.

Authors
Vo-Dinh, T; Chi, Z; Cullum, B; Mobley, J; Miller, GH
MLA Citation
Vo-Dinh, T, Chi, Z, Cullum, B, Mobley, J, and Miller, GH. "Laser-induced fluorescence studies of polyaromatic hydrocarbons (PAH) vapors at high temperatures." International Symposium on Combustion Abstracts of Accepted Papers B (2000): 486--.
Source
scival
Published In
International Symposium on Combustion Abstracts of Accepted Papers
Issue
B
Publish Date
2000
Start Page
486-

DNA biochip using a phototransistor integrated circuit.

This work describes the development of an integrated biosensor based on phototransistor integrated circuits (IC) for use in medical detection, DNA diagnostics, and gene mapping. The evaluation of various system components developed for an integrated biosensor microchip is discussed. Methods to develop a microarray of DNA probes on nitrocellulose substrate are discussed. The biochip device has sensors, amplifiers, discriminators, and logic circuitry on board. Integration of light-emitting diodes into the device is also possible. To achieve improved sensitivity, we have designed an IC system having each phototransistor sensing element composed of 220 phototransistor cells connected in parallel. Measurements of fluorescent-labeled DNA probe microarrays and hybridization experiments with a sequence-specific DNA probe for the human immunodeficiency virus 1 system on nitrocellulose substrates illustrate the usefulness and potential of the DNA biochip.

Authors
Vo-Dinh, T; Alarie, JP; Isola, N; Landis, D; Wintenberg, AL; Ericson, MN
MLA Citation
Vo-Dinh, T, Alarie, JP, Isola, N, Landis, D, Wintenberg, AL, and Ericson, MN. "DNA biochip using a phototransistor integrated circuit." Anal Chem 71.2 (January 15, 1999): 358-363.
PMID
9949727
Source
pubmed
Published In
Analytical Chemistry
Volume
71
Issue
2
Publish Date
1999
Start Page
358
End Page
363

Near infrared (NIR) emitter/detector probe for sensing buried objects and landmines

The detection of landmines and buried objects requires methods that can cover large areas rapidly while providing the required sensitivity to detect the optical and spectroscopic contrast in soil properties that can reveal their presence. These conditions on contrast and coverage can be met by capturing images of the soil at wavelengths which are sensitive to the properties modified by the presence of buried objects. In this work we investigate both NIR scanning methods which may have some utility for the detection problem. For the scanning method, we acquire data point-by-point over a two-dimensional grid with a single emitter/detector probe. The soil (or sand) above a shallow buried object can be differentiated from the surrounding soil by detecting the difference in relative water content. Moist soil absorbs more near-infrared (NIR) incident light than dry soil. A light-emitting diode (LED) operating at 900 nm and a photodiode sensitive to NIR radiation formed the emitter/detector (ED) probe used in this study. The ED probe was mounted side-by-side and scanned over a surface in a two-dimensional grid as readings were collected point-by-point. The results indicated that this simple NIR emitter/detector probe discriminated between soils of varying water contents with an imaging resolution of 4 millimeters. To illustrate how imaging techniques can be used in this application, the fluorescence image of a landmine casing is presented. The results illustrate the potential of these two approaches for detection of landmines and buried objects.

Authors
Miller, GH; Culbertson, SC; Mobley, J; DiMarzio, C; Vo-Dinh, T
MLA Citation
Miller, GH, Culbertson, SC, Mobley, J, DiMarzio, C, and Vo-Dinh, T. "Near infrared (NIR) emitter/detector probe for sensing buried objects and landmines." Proceedings of SPIE - The International Society for Optical Engineering 3752 (1999): 307-313.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3752
Publish Date
1999
Start Page
307
End Page
313

Photoacoustic measurements in brain tissue

In this work, we develop and evaluate the photoacoustic technique for recording spectra of white and gray mammalian brain tissues. In additional to the experimental work, we also discuss the geometric aspects of photoacoustic signal generation using collimated light. Spectra constructed from the peak-to-peak amplitude of the photoacoustic waveforms indicate differences in the two tissue types at wavelengths between 620 and 695 nm. The potential of the technique for non-invasive diagnosis is discussed.

Authors
Mobley, J; Kasili, PM; Vo-Dinh, T
MLA Citation
Mobley, J, Kasili, PM, and Vo-Dinh, T. "Photoacoustic measurements in brain tissue." Proceedings of SPIE - The International Society for Optical Engineering 3595 (1999): 210-218.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3595
Publish Date
1999
Start Page
210
End Page
218

Surface-enhanced Raman scattering (SERS) method and instrumentation for genomics and biomedical analysis

The development of a surface-enhanced Raman scattering (SERS) method and instrument for use in biomedical and genomics analysis is described. The technology uses DNA gene probes based on SERS labels for gene detection and DNA mapping. The detection method uses nanostructured metallic substrates as SERS-active platforms. The surface-enhanced Raman gene (SERGen) probes can be used to detect DNA targets via hybridization to DNA sequences complementary to these probes. The probes do not require the use of radioactive labels and have great potential to provide both sensitivity and selectivity. Advanced instrumental systems designed for point-source spectral measurements and for multi-spectral imaging (MSI) are described. The MSI concept allows receding the entire SERS spectrum for every pixel on the two-dimensional hybridization platform in the field of view with the use of a rapid-scanning solid-state device, such as the acousto-optic tunable filter (AOTF). The usefulness of the SERGen approach and its applications in biomedical diagnostics, high-throughput analysis and DNA mapping and sequencing are discussed. Copyright © 1999 John Wiley & Sons, Ltd.

Authors
Vo-Dinh, T; Stokes, DL; Griffin, GD; Volkan, M; Kim, UJ; Simon, MI
MLA Citation
Vo-Dinh, T, Stokes, DL, Griffin, GD, Volkan, M, Kim, UJ, and Simon, MI. "Surface-enhanced Raman scattering (SERS) method and instrumentation for genomics and biomedical analysis." Journal of Raman Spectroscopy 30.9 (1999): 785-793.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
30
Issue
9
Publish Date
1999
Start Page
785
End Page
793

Signal expressions and initial design for a 3-D ORAM radiation dosimeter reader

Three-dimensional optical memories which utilize two-photon processes have been proposed for use as a radiation dosimeter. The 'bits' stored by the optical memory are altered by the passage of radiation and can yield information about the dose and energy. In this work, the 'write' process of a two-photon optical memory is examined. This process uses a crossed-beam excitation scheme. By considering the spatial and temporal properties of the excitation sources used to drive the two-photon transitions, conditions are derived under which the number of absorption events due to the crossed-beams acting together outnumber the background events.

Authors
Mobley, J; Bogard, JS; Moscovitch, M; Vo-Dinh, T
MLA Citation
Mobley, J, Bogard, JS, Moscovitch, M, and Vo-Dinh, T. "Signal expressions and initial design for a 3-D ORAM radiation dosimeter reader." Proceedings of SPIE - The International Society for Optical Engineering 3534 (1999): 519-530.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3534
Publish Date
1999
Start Page
519
End Page
530

Subwavelength Raman imaging of biological samples using near-field spectroscopy

Scanning near-field optical microscopy (SNOM) and Raman scattering were combined to obtain subwavelength molecular resolution. Near-field microscopy allows to overcome the diffraction limit valid for all lens or mirror based optical instruments and lateral resolutions well below 100 nm have been claimed. Raman spectroscopy yields information on the vibrational states of a molecule and therefore allows to distinguish between different chemical compounds easily. This is an advantage to the more widely used near-field fluorescence microscopy. To enhance the notoriously weak near-field Raman signal the sample was brought onto a Raman enhancing surface (silver coated Teflon nanospheres). Additionally brilliant cresyl blue (BCB) acted as a Raman label for our DNA samples. On such samples Raman images with a resolution better than 100 nm have been obtained. A single near-field SERS spectrum was measured in approximately 60 seconds. The acquisition time currently depends critically on the transmission of the near-field probes. Nevertheless, it is possible to measure whole near-field Raman images in a reasonable time. From these Raman images a preliminary distinction of different constitutions of adsorbed molecules can be done.

Authors
Deckert, V; Zeisel, D; Zenobi, R; Vo-Dinh, T
MLA Citation
Deckert, V, Zeisel, D, Zenobi, R, and Vo-Dinh, T. "Subwavelength Raman imaging of biological samples using near-field spectroscopy." Proceedings of SPIE - The International Society for Optical Engineering 3607 (1999): 8-15.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3607
Publish Date
1999
Start Page
8
End Page
15

AOTF-based remote sensor with sol-gel probe

We report the development and application of a sensor using acousto-optic tunable filter (AOTF) and sol-gel probe technology. A pH-sensitive probe is used as a model sensing system with dextran derivatives of pH sensitive dyes doped into sol-gel thin films. We used a unique combination of pH-sensitive and pH-insensitive dual-label dye system. For optimization studies, the performance of these films as a pH sensing probe was evaluated using synchronous fluorescence detection. The performance of the a prototype AOTF-based monitor using a low-power argon laser as an ion excitation source was evaluated.

Authors
Volkan, M; Yuan, L; Vo-Dinh, T
MLA Citation
Volkan, M, Yuan, L, and Vo-Dinh, T. "AOTF-based remote sensor with sol-gel probe." Instrumentation Science and Technology 27.5 (1999): 343-355.
Source
scival
Published In
Instrumentation Science and Technology
Volume
27
Issue
5
Publish Date
1999
Start Page
343
End Page
355

Development of instrumental ORAM system for radiation dosimetry

The development of an optical-based dosimeter for neutrons and heavy charged particles is described. It is based on the use of three dimensional (3-D) optical memory materials, used in optical computing applications, and multiphoton fluorescence of photochromic dyes. Development and characterization of various types of dosimeter materials are described as well as the optical readout system. In addition, various excitation geometries for `reading' and `writing' to the optical memories are also discussed.

Authors
Cullum, BM; Mobley, J; Bogard, JS; Moscovitch, M; Vo-Dinh, T
MLA Citation
Cullum, BM, Mobley, J, Bogard, JS, Moscovitch, M, and Vo-Dinh, T. "Development of instrumental ORAM system for radiation dosimetry." Proceedings of SPIE - The International Society for Optical Engineering 3853 (1999): 376-384.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3853
Publish Date
1999
Start Page
376
End Page
384

Mag-indo-1-protein interaction as a tool for probing the 3D conformation of protein sub-domains: Influence of the chemical microenvironment of the histidin residue(s) on the parameters of the interaction

Magnesium complexation with Mag-indo-1 results in a shift of the emission fluorescence spectrum from 480 nm to 417 nm. Mag-indo-1 is also able to bind calcium and zinc. These cationic interactions induce the same spectral shift but the fluorescence intensity and the dissociation constant are dependent of the nature of the cation. Furthermore Mag-indo-1 bind also proteins through a specific interaction with some histidin residues. That interaction induces a characteristic spectral shift of the emission fluorescence spectra from 480 to 457 nM. Emission and synchronous fluorescence techniques have been used to monitor that interaction with proteins such as turkey and hen white egg lysozymes. Using a method of resolution of complex fluorescence spectra, it has been possible to calculate the number of interaction sites and the correlative dissociation constants. Depending on the nature of the protein a quenching of the natural fluorescence of the protein was observed, associated with an energy transfer from some tryptophan(s) to Mag-indo-1. Moreover the value of the dissociation constant was found dependent of the molecular microenvironment of the histidin residue. These results suggest that Mag-indo-1 could be used as an intramolecular fluorescent ruler to explore the changes in 3D conformation resulting from genetically induced amino-acid substitutions and to monitor changes in the chemical microenvironment of specific sub-domains of these proteins.

Authors
Viallet, PM; Vo-Dinh, T; Bunde, T; Ribou, A-C; Vigo, J; Salmon, J-M
MLA Citation
Viallet, PM, Vo-Dinh, T, Bunde, T, Ribou, A-C, Vigo, J, and Salmon, J-M. "Mag-indo-1-protein interaction as a tool for probing the 3D conformation of protein sub-domains: Influence of the chemical microenvironment of the histidin residue(s) on the parameters of the interaction." Proceedings of SPIE - The International Society for Optical Engineering 3595 (1999): 231-242.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3595
Publish Date
1999
Start Page
231
End Page
242

Monitoring system for the study of autotrophic biofilms in bioremediation of polyaromatic compounds

A portable laser-induced fluorescence device was developed for detecting polyaromatic hydrocarbons (PAHs). The device was tested in the laboratory by using anthracene and pyrene PAHs model systems. These PAHs were successfully field screened in surface water and natural algae systems by using the developed device.

Authors
Alarie, JP; Bruttig, A; Miller, GH; Hill, W; Vo-Dinh, T
MLA Citation
Alarie, JP, Bruttig, A, Miller, GH, Hill, W, and Vo-Dinh, T. "Monitoring system for the study of autotrophic biofilms in bioremediation of polyaromatic compounds." Proceedings of SPIE - The International Society for Optical Engineering 3534 (1999): 670-676.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3534
Publish Date
1999
Start Page
670
End Page
676

A new surface-enhanced Raman scattering substrate based on silver nanoparticles in sol-gel

We report for the first time the development of a new surface-enhanced Raman scattering (SERS)-active silver chloride silica-glass substrate prepared by using in situ precipitation of silver chloride particles in sol-gel films as a precursor for nanoparticles of silver. The controlled precipitation of silver chloride was achieved by the reaction of silver nitrate with trichloroacetic acid, which leads to a slow release of chloride ions. Silver chloride particles were reduced to silver nanoparticles by FeSO4·7H2O. The sol-gel films prepared exhibit good optical properties and induce a strong SERS effect for several model compounds, including cresyl fast violet and brilliant cresyl blue. Optimization studies of substrate preparation and coating conditions were performed and are discussed in detail. The performance of this new substrate compares favorably with those of previously developed silver-coated alumina substrates. The SERS spectra of other compounds of environmental and biological interest, such as 1-aminonaphthalene, 2-aminopyrimidine, pyridine and p-aminobenzoic acid, were investigated to illustrate the usefulness of this novel type of SERS substrate for use in chemical and biological analysis. Copyright © 1999 John Wiley & Sons, Ltd.

Authors
Volkan, M; Stokes, DL; Vo-Dinh, T
MLA Citation
Volkan, M, Stokes, DL, and Vo-Dinh, T. "A new surface-enhanced Raman scattering substrate based on silver nanoparticles in sol-gel." Journal of Raman Spectroscopy 30.12 (1999): 1057-1065.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
30
Issue
12
Publish Date
1999
Start Page
1057
End Page
1065

Hyperspectral imaging using AOTF and NIR sensing of buried objects and landmines

The detection of landmines and buried objects requires methods that can cover large areas rapidly while providing the required sensitivity to detect the optical and spectroscopic contrasts in soil properties that can reveal their presence. These conditions on contrast and coverage can be met by capturing images of the soil at wavelengths which are sensitive to the properties modified by the presence of buried objects. In this work we investigate both imaging and scanning methods which may have some utility for the detection problem. In the imaging approach, we capture hyperspectral reflection images using an acousto-optic tunable filter (AOTF) and fluorescence images using a long-pass filter. For the scanning method, we acquire data point-by-point over a two-dimensional grid with a single emitter/detector pair. The results illustrate the potential of these two approaches for detection of landmines and buried objects.

Authors
Mobley, J; Miller, GH; Kasili, PM; DiMarzio, C; Vo-Dinh, T
MLA Citation
Mobley, J, Miller, GH, Kasili, PM, DiMarzio, C, and Vo-Dinh, T. "Hyperspectral imaging using AOTF and NIR sensing of buried objects and landmines." Proceedings of SPIE - The International Society for Optical Engineering 3534 (1999): 321-327.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3534
Publish Date
1999
Start Page
321
End Page
327

Application of ultrasonic techniques for brain injury diagnosis

In this work, we evaluate methods for detecting brain injury using ultrasound. We have used simulations of ultrasonic fields in the head to model the phase distortion of the skull. In addition we present experimental data from the crania of large animals. The experimental data help us understand and evaluate the performance of different transducers in acquiring the backscatter data from the brain through the skull. Both the simulations and acquired data illustrate the superiority of lower-frequency (< = 1 MHz) ultrasonic fields for transcranial acquisition of signals from inside the brain. Additionally, the experimental work shows that the higher-frequency (5 MHz) ultrasound can also be useful in acquiring clean nearfield data to help detect the position of the inner boundary of the skull.

Authors
Mobley, J; Kasili, PM; Norton, SJ; Vo-Dinh, T
MLA Citation
Mobley, J, Kasili, PM, Norton, SJ, and Vo-Dinh, T. "Application of ultrasonic techniques for brain injury diagnosis." Proceedings of SPIE - The International Society for Optical Engineering 3595 (1999): 79-90.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3595
Publish Date
1999
Start Page
79
End Page
90

Fiber optics SERS sensors for environmental monitoring

The development of fiberoptic sensors for remote in-situ environmental monitoring using surface-enhanced Raman scattering (SERS) is described. The approach to sensor development includes the initial development of SERS-active media on nanoparticle-based solid-surface substrates. These media are generally metal-coated nanoparticles that can be further modified for enhanced chemical selectivity, longevity and ruggedness. One example of surface modification is the application of a permeability-selective polymer, polyvinyl pyrrolidone (PVP). For remote environmental sensing applications, the planar solid SERS substrates have been successfully incorporated in a two-fiber probe design. We have also applied SERS-active media directly to an optical fiber as an integrated single-fiber design. Such sensors occupy much less volume and promote non intrusive monitoring systems. Linear response of the integrated sensor monitoring systems for various environmental chemicals with excellent correlation (> 0.99) has been observed in the part-per-billion (ppb) range.

Authors
Stokes, DL; Alarie, JP; Ananthanarayanan, V; Vo-Dinh, T
MLA Citation
Stokes, DL, Alarie, JP, Ananthanarayanan, V, and Vo-Dinh, T. "Fiber optics SERS sensors for environmental monitoring." Proceedings of SPIE - The International Society for Optical Engineering 3534 (1999): 647-654.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3534
Publish Date
1999
Start Page
647
End Page
654

Demonstration of a separations-based fiberoptic sensor for bioanalysis

We present a newly-developed separations-based fiberoptic sensor (SBFOS) for biomedical applications. The sensor features a linear 10 cm effective length section of capillary coupled with a single optical fiber for laser- induced fluorescence (LIF) detection of fluorescently-labeled analytes separated by capillary electrophoresis (CE). The single optical fiber, arranged perpendicular to and touching the capillary, transmits both laser excitation to the sensor and analytical signal from the sensor to a PMT-based detection system. The resulting compact, robust design may prove to be an attractive alternative to conventional CE laboratory systems due to the portability and potential for automation and multiplexing. The sensor has been evaluated with size selective separations of φX-174 HaeIII digest DNA samples. Baseline resolution for fragments differing by 10 base pairs was routinely observed in separations requiring approximately 10 min. This short analysis time, combined with rapid sensor regeneration capability, enabled the temporal analysis of a digestion of φX-174 phage DNA by HaeIII restriction enzyme. The use of viscous matrices permits sensor operation in any orientation without introducing complications associated with gravity- driven hydrostatic flow. Relative standard deviations in migration rates of the φX-174 DNA fragments have generally been less than 5%. Furthermore, efficiencies of up to 2.5 million plates/m have been observed, giving the compact sensor a separation quality which is competitive with larger conventional CE systems.

Authors
Stokes, DL; Sepaniak, MJ; Vo-Dinh, T
MLA Citation
Stokes, DL, Sepaniak, MJ, and Vo-Dinh, T. "Demonstration of a separations-based fiberoptic sensor for bioanalysis." Analytica Chimica Acta 399.3 (1999): 201-212.
Source
scival
Published In
Analytica Chimica Acta
Volume
399
Issue
3
Publish Date
1999
Start Page
201
End Page
212
DOI
10.1016/S0003-2670(99)00463-8

Evaluation of a chemical vapor dosimeter using polymer-coated SERS substrates

This paper describes the development and evaluation of an improved passive chemical dosimeter using poly(vinylpyrrolidone) coating on a surface- enhanced Raman scattering (SERS) substrate for monitoring airborne chemicals. Experimental studies are performed to demonstrate the longevity, enhancement of Raman signals, and selectivity of the dosimeter. The new substrate has been used to monitor exposure to vapors of benzoic acid, 2-aminopyrimidine, and 2,4-dinitrophenol over 20-day periods. The improved performance of the newly developed polymer-coated substrate is compared to that of uncoated SERS substrates. Results of substrate optimization and shelf-life studies are discussed.

Authors
Stokes, DL; Pal, A; Narayanan, VA; Vo-Dinh, T
MLA Citation
Stokes, DL, Pal, A, Narayanan, VA, and Vo-Dinh, T. "Evaluation of a chemical vapor dosimeter using polymer-coated SERS substrates." Analytica Chimica Acta 399.3 (1999): 265-274.
Source
scival
Published In
Analytica Chimica Acta
Volume
399
Issue
3
Publish Date
1999
Start Page
265
End Page
274
DOI
10.1016/S0003-2670(99)00462-6

Vibrational spectrum of strychnine: Detection at the nanogram level using a Raman microscope

The complete vibrational spectra of strychnine is reported. Strychnine, a compound with medicinal value at the proper dosage, is also a potent toxin at certain concentration levels. Down to 5 ng of strychnine were detected from its spectrum using a microscope attached to a Raman spectrophotometer. The complete Raman and Fourier transform IR spectra were also recorded for positive identification. The prominent vibrational band wavenumbers useful as a reference source for the identification of strychnine in an emergency situation are discussed. The Raman spectra of a bulk sample and of a strychnine microcrystal are given to facilitate positive identification. The potential application of the vibrational analysis of strychnine for forensic diagnostics is discussed. Copyright © 1999 John Wiley & Sons, Ltd.

Authors
Narayanan, VA; Stump, NA; Cul, GDD; Vo-Dinh, T
MLA Citation
Narayanan, VA, Stump, NA, Cul, GDD, and Vo-Dinh, T. "Vibrational spectrum of strychnine: Detection at the nanogram level using a Raman microscope." Journal of Raman Spectroscopy 30.6 (1999): 435-439.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
30
Issue
6
Publish Date
1999
Start Page
435
End Page
439

Surface-enhanced Raman detection of chemical vapors with the use of personal dosimeters

This article provides an overview of the development and application of surface-enhanced Raman scattering (SERS) for the detection of vapors of organic chemicals with the use of personal dosimetry. The approach used with this personal dosimeter requires no sample desorption or wet-chemical extraction procedure. The dosimeter employs the SERS technique for direct measurement of the amount of analyte collected on the sample substrate. SERS substrates based on nano-particles developed in our laboratory have been incorporated in this dosimeter design. Polymers applied to these solid-based SERS substrates can further enhance dosimeter shelf life, ruggedness, and chemical selectivity. Use of this SERS dosimeter for the determination of time-weighted average exposures to chemical vapors has been demonstrated. © 1999 John Wiley & Sons, Inc.

Authors
Vo-Dinh, T; Stokes, DL
MLA Citation
Vo-Dinh, T, and Stokes, DL. "Surface-enhanced Raman detection of chemical vapors with the use of personal dosimeters." Field Analytical Chemistry and Technology 3.6 (1999): 346-356.
Source
scival
Published In
Field Analytical Chemistry and Technology
Volume
3
Issue
6
Publish Date
1999
Start Page
346
End Page
356

Differentiation of normal and neoplastic cells by synchronous fluorescence: Rat liver epithelial and rat hepatoma cell models

In the present study, conventional and synchronous luminescence (SL) were utilized to investigate spectral differences in normal and neoplastic cells. The synchronous fluorescence (SE) method involves scanning simultaneously both emission and excitation wavelengths while keeping a constant wavelength interval between them. This SE procedure simplifies the emission spectrum and provides for greater selectivity and is used to detect subtle differences in the fluorescence emission of the biochemical species of cells from rat tissues. A difference between the fluorescent spectra of the normal rat liver epithelial (RLE) and hepatoma cell lines were detected using synchronous fluorescence. The potential use of SE as a screening tool for cancer diagnosis is discussed.

Authors
Watts, WE; Isola, NR; Frazier, D; Vo-Dinh, T
MLA Citation
Watts, WE, Isola, NR, Frazier, D, and Vo-Dinh, T. "Differentiation of normal and neoplastic cells by synchronous fluorescence: Rat liver epithelial and rat hepatoma cell models." Analytical Letters 32.13 (1999): 2583-2594.
Source
scival
Published In
Analytical Letters
Volume
32
Issue
13
Publish Date
1999
Start Page
2583
End Page
2594

Monitoring and characterization of polyaromatic compounds in the environment.

This paper provides an overview of analytical techniques and instruments used to monitor and characterize polycyclic aromatic compounds (PACs) in the environment. The basic operating principles of various analytical approaches and systems are presented. The review deals specifically with spectroscopic methods, chromatographic and hyphenated techniques, and field monitoring devices. Emphasis is given to portable devices that can be used under field conditions. Specific examples of analytical techniques and instruments developed in the authors's laboratories will be discussed to illustrate the usefulness and potential of these approaches for environmental monitoring and characterization of PACs.

Authors
Vo-Dinh, T; Fetzer, J; Campiglia, AD
MLA Citation
Vo-Dinh, T, Fetzer, J, and Campiglia, AD. "Monitoring and characterization of polyaromatic compounds in the environment." Talanta 47.4 (November 1998): 943-969.
PMID
18967400
Source
pubmed
Published In
Talanta
Volume
47
Issue
4
Publish Date
1998
Start Page
943
End Page
969

Single- and dual-fractal analysis of hybridization binding kinetics: biosensor applications.

The diffusion-limited hybridization kinetics of analyte in solution to a receptor immobilized on a biosensor or immunosensor surface is analyzed within a fractal framework. The data may be analyzed by a single- or a dual-fractal analysis. This was indicated by the regression analysis provided by Sigmaplot. It is of interest to note that the binding rate coefficient and the fractal dimension both exhibit changes in the same direction for both the single-fractal and the dual-fractal analysis examples presented. For example, for a single-fractal analysis and for the hybridization of 10 nM 16CFl (oligonucleotide) to 16B immobilized via sulfosuccinimidyl-6-(biotinamido)hexanoate and streptavidin using chemical and thermal regeneration (Abel, A. P.; Weller, M. G.; Duveneck, G. L.; Ehrat, M. Widmer, H. M. Anal. Chem. 1996, 68, 2905-2912), an increase in the fractal dimension, Df from 1.211 (chemical regeneration) to 1.394 (thermal regeneration), leads to an increase in the binding rate coefficient, k, from 86.53 (chemical regeneration) to 100.0 (thermal regeneration). An increase in the degree of heterogeneity on the biosensor surface leads to an increase in the binding rate coefficient. When a dual-fractal analysis was utilized, an increase in the fractal dimension value from Df1 to Df2 leads to an increase in the binding rate coefficient value from k1 to k2. The fractional order of dependence of the binding rate coefficient, k1, on (a) the analyte (rRNA) concentration in solution and (b) on the fractal dimension, Df1, for the hybridization kinetics to detect Listeria species (Fliss, R.; St-Laurent, M.; Emond, E.; Simard, R. E.; Lemieux, R.; Ettriki, A.; Pandian, S. Appl. Microbiol. Biotechnol. 1995, 43, 717-724.) further reinforces the fractal nature of the system. The binding rate coefficient(s) expressions developed as a function of the analyte concentration in solution and the fractal dimension are of particular value since they provide a means to better control of biosensor or immunosensor performance.

Authors
Sadana, A; Vo-Dinh, T
MLA Citation
Sadana, A, and Vo-Dinh, T. "Single- and dual-fractal analysis of hybridization binding kinetics: biosensor applications." Biotechnol Prog 14.5 (September 1998): 782-790.
PMID
9758669
Source
pubmed
Published In
Biotechnology Progress
Volume
14
Issue
5
Publish Date
1998
Start Page
782
End Page
790
DOI
10.1021/bp980081r

Near-Field Surface-Enhanced Raman Imaging of Dye-Labeled DNA with 100-nm Resolution.

Raman chemical imaging on a scale of 100 nm is demonstrated for the first time. This is made possible by the combination of scanning near-field optical microscopy (SNOM or NSOM) and surface-enhanced Raman scattering (SERS), using brilliant cresyl blue (BCB)-labeled DNA as a sample. SERS substrates were produced by evaporating silver layers on Teflon nanospheres. The near-field SERS spectra were measured with an exposure time of 60 s and yielded good signal-to-noise ratios (25:1). The distinction between reflected light from the excitation laser and Raman scattered light allows the local sample reflectivity to be separated from the signal of the adsorbed DNA molecules. This is of general importance to correct for topographic coupling that often occurs in near-field optical imaging. The presented data show a lateral dependence of the Raman signals that points to special surface sites with particularly high SERS enhancement.

Authors
Deckert, V; Zeisel, D; Zenobi, R; Vo-Dinh, T
MLA Citation
Deckert, V, Zeisel, D, Zenobi, R, and Vo-Dinh, T. "Near-Field Surface-Enhanced Raman Imaging of Dye-Labeled DNA with 100-nm Resolution." Anal Chem 70.13 (July 1, 1998): 2646-2650.
PMID
21644784
Source
pubmed
Published In
Analytical Chemistry
Volume
70
Issue
13
Publish Date
1998
Start Page
2646
End Page
2650
DOI
10.1021/ac971304f

Surface-enhanced Raman gene probe for HIV detection.

We report, for the first time, the use of surface-enhanced Raman (SERS)-active labels for primers used in polymerase chain reaction amplification of specific target DNA sequences. This method has the potential for combining the spectral selectivity and high sensitivity of the SERS technique with the inherent molecular specificity offered by DNA sequence hybridization. The effectiveness of the detection scheme is demonstrated using the gag gene sequence of the human immunodeficiency virus. The potential use of multiple probes for simultaneous detection of multiple biological targets is discussed.

Authors
Isola, NR; Stokes, DL; Vo-Dinh, T
MLA Citation
Isola, NR, Stokes, DL, and Vo-Dinh, T. "Surface-enhanced Raman gene probe for HIV detection." Anal Chem 70.7 (April 1, 1998): 1352-1356.
PMID
9553492
Source
pubmed
Published In
Analytical Chemistry
Volume
70
Issue
7
Publish Date
1998
Start Page
1352
End Page
1356

Near-field surface-enhanced Raman spectroscopy of dye molecules adsorbed on silver island films

Authors
Zeisel, D; Deckert, V; Zenobi, R; Vo-Dinh, T
MLA Citation
Zeisel, D, Deckert, V, Zenobi, R, and Vo-Dinh, T. "Near-field surface-enhanced Raman spectroscopy of dye molecules adsorbed on silver island films." CHEMICAL PHYSICS LETTERS 283.5-6 (February 13, 1998): 381-385.
Source
wos-lite
Published In
Chemical Physics Letters
Volume
283
Issue
5-6
Publish Date
1998
Start Page
381
End Page
385
DOI
10.1016/S0009-2614(97)01391-2

Laser-induced fluorescence for esophageal cancer and dysplasia diagnosis.

A method using laser-induced fluorescence (LIF) for in vivo cancer diagnosis of the esophagus is described. Autofluorescence of normal and malignant tissues was measured directly using a fiberoptic probe inserted through an endoscope. The measurements were performed in vivo during routine endoscopy. Measurement of the fluorescence signal from the tissue was performed using laser excitation at 410 nm. The methodology was applied to differentiate normal and malignant tumors of the esophagus. The results of this LIF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal and malignant tumors for the samples investigated. The LIF procedure could lead to the development of a rapid and cost-effective technique for cancer diagnosis.

Authors
Vo-Dinh, T; Panjehpour, M; Overholt, BF
MLA Citation
Vo-Dinh, T, Panjehpour, M, and Overholt, BF. "Laser-induced fluorescence for esophageal cancer and dysplasia diagnosis." Ann N Y Acad Sci 838 (February 9, 1998): 116-122.
PMID
9511800
Source
pubmed
Published In
Annals of the New York Academy of Sciences
Volume
838
Publish Date
1998
Start Page
116
End Page
122

Surface-enhanced Raman spectroscopy using metallic nanostructures

This article provides an overview of the development and application of the surface-enhanced Raman scattering (SERS) techniques using metal-coated nanostructures on solid substrates. An introduction to theoretical principles of the SERS effect and the different SERS-active media is presented. The focus is on nanostructured solid substrates and their practical applications in chemical, environmental and biomedical areas. Specific examples of analytical techniques, instruments and sensors developed in the author's laboratory will be discussed to illustrate the usefulness and potential of the SERS techniques. Copyright (C) 1998 Elsevier Science B.V.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Surface-enhanced Raman spectroscopy using metallic nanostructures." TrAC - Trends in Analytical Chemistry 17.8-9 (1998): 557-582.
Source
scival
Published In
Trends in Analytical Chemistry
Volume
17
Issue
8-9
Publish Date
1998
Start Page
557
End Page
582
DOI
10.1016/S0165-9936(98)00069-7

Diffraction tomographic imaging with photon density waves: An explicit solution

An explicit formula is derived for reconstructing tissue inhomogeneities from scattered photon-density waves. When intensity-modulated light is used as a source, such waves obey a Helmholtz equation with a complex wave number. A process of analytical continuation in the spatial-frequency domain is used to make this wave number real, whereupon inversion formulas based on conventional diffraction tomography are applied to invert the data to yield an image. In this way an explicit solution to the inverse problem can be derived within the Born approximation. Here the spatially varying quantity imaged is a linear combination of the transport scattering and absorption coefficients. Data are assumed measured at one modulation frequency, but multiple modulation frequencies could in principle be used to generate independent images of the scattering and absorption coefficients. © 1998 Optical Society of America.

Authors
Norton, SJ; Vo-Dinh, T
MLA Citation
Norton, SJ, and Vo-Dinh, T. "Diffraction tomographic imaging with photon density waves: An explicit solution." Journal of the Optical Society of America A: Optics and Image Science, and Vision 15.10 (1998): 2670-2677.
Source
scival
Published In
Journal of the Optical Society of America. A, Optics and image science
Volume
15
Issue
10
Publish Date
1998
Start Page
2670
End Page
2677

Use of transmitted room-temperature phosphorescence to improve nalidixic acid determination

A method for nalidixic acid (NA) determination by transmitted room-temperature phosphorescence is proposed. The antibacterial agent NA in acidic solution shows native fluorescence; when NA is spotted on a filter paper precoated with β-cyclodextrin and lead (II) acetate and dried for 5 min, phosphorescence results. The transmitted phosphorescence was measured directly with the use of a homemade sample holder. The excitation and emission wavelengths were 330 and 417 nm, respectively. The applicable concentration range was between 0.06 and 4.50 μg/mL with a relative standard deviation of 2.8% and a detection limit of 0.02 μg/mL. The method was applied to the determination of NA in human urine and pharmaceuticals, with recoveries from 97.5 to 105.5%.

Authors
Capitán-Vallvey, LF; Ojeda, F; Olmo, MD; Avidad, R; Navalón, A; Vo-Dinh, T
MLA Citation
Capitán-Vallvey, LF, Ojeda, F, Olmo, MD, Avidad, R, Navalón, A, and Vo-Dinh, T. "Use of transmitted room-temperature phosphorescence to improve nalidixic acid determination." Applied Spectroscopy 52.1 (1998): 101-105.
Source
scival
Published In
Applied Spectroscopy
Volume
52
Issue
1
Publish Date
1998
Start Page
101
End Page
105

Development of a DNA biochip for gene diagnosis

We describe a biochip based on an integrated circuit photodiode array for use in medical diagnostics. The biochip is a self-contained device which has photosensors, amplifiers, discriminators and logic circuitry on board. The development and evaluation of various microchip system components of the genosensor are discussed. The performance of the DNA biochip device is illustrated with fluorescence detection of DNA probes specific to gene fragments of the human immuno-deficiency virus 1 (HIV1) system. The usefulness and potential of the DNA biochip technology for rapid and cost-effective medical diagnostics is discussed.

Authors
Vo-Dinh, T; Wintenberg, AL; Ericson, MN; Isola, N; Alarie, JP
MLA Citation
Vo-Dinh, T, Wintenberg, AL, Ericson, MN, Isola, N, and Alarie, JP. "Development of a DNA biochip for gene diagnosis." Proceedings of SPIE - The International Society for Optical Engineering 3253 (1998): 27-33.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3253
Publish Date
1998
Start Page
27
End Page
33
DOI
10.1117/12.308046

SERODS: A new medium for high-density optical data storage

A new optical data storage technology based on the surface-enhanced Raman scattering (SERS) effect has been developed for high-density optical memory and three-dimensional data storage. With the surface-enhanced Raman optical data storage (SERODS) technology, the molecular interactions between the optical layer molecules and the nanostructured metal substrate are modified by the writing laser, changing their SERS properties to encode information as bits. Since the SERS properties are extremely sensitive to molecular nano-environments, very small "spectrochemical holes" approaching the diffraction limit can be produced for the writing process. The SERODS device uses a reading laser to induce the SERS emission of molecules on the disk and a photometric detector tuned to the frequency of the Raman spectrum to retrieve the stored information. The results illustrate that SERODS is capable of three-dimensional data storage and has the potential to achieve higher storage density than currently available optical data storage systems.

Authors
Vo-Dinh, T; Stokes, DL
MLA Citation
Vo-Dinh, T, and Stokes, DL. "SERODS: A new medium for high-density optical data storage." Proceedings of SPIE - The International Society for Optical Engineering 3401 (1998): 284-290.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3401
Publish Date
1998
Start Page
284
End Page
290
DOI
10.1117/12.327949

Mag-indo-1 as a potential reporter of the 3D conformation of protein sub-domains

Mag-indo-1 is a well known fluorescent probe. Magnesium complexation results in a shift of the emission fluorescence spectrum from 480 nm to 417 nm with an intensity proportional to the magnesium concentration in the range 0.6 to 30 mM. Although designed as a specific magnesium chelator, Mag-indo-1 is also able to bind calcium and zinc. All these cationic interactions induce the same spectral shift but the fluorescence intensity and the dissociation constant are dependent of the nature of the cation. Furthermore Mag-indo-1 can also bind proteins through a specific interaction with some histidin residues. That interaction induces a characteristic spectral shift of the emission fluorescence spectra from 480 to 457 nM. All these properties suggest that Mag-indo-1 could be used to study the protein-cation binding. Emission and synchronous fluorescence techniques have been used to monitor that interaction with proteins such as bovin serum albumin, human serum albumin, turkey white egg lysozyme. Using a method of resolution of complex fluorescence spectra, it has been possible to calculate the number of interaction sites and the correlative dissociation constants. Depending on the nature of the protein a quenching of the natural fluorescence of the protein was observed, associated with an energy transfer from some tryptophan(s) to Mag-indo-1. All these data were tentatively correlated with the available information on the 3D conformation of the proteins. These results suggest that Mag-indo-1 could be used as an intramolecular fluorescent ruler to monitor the changes in 3D conformation of specific sub-domains of proteins.

Authors
Viallet, PM; Vo-Dinh, T; Bunde, T; Ribou, A-C; Vigo, J; Salmon, J-M
MLA Citation
Viallet, PM, Vo-Dinh, T, Bunde, T, Ribou, A-C, Vigo, J, and Salmon, J-M. "Mag-indo-1 as a potential reporter of the 3D conformation of protein sub-domains." Proceedings of SPIE - The International Society for Optical Engineering 3253 (1998): 238-249.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3253
Publish Date
1998
Start Page
238
End Page
249
DOI
10.1117/12.308035

Evaluation of ultrasound techniques for brain injury detection

In this work we examine the physics underlying wave propagation in the head to evaluate various ultrasonic transducers for use in a brain injury detection device. The results of measurements of the attenuation coefficient and phase velocity for ultrasonic propagation in samples of brain tissue and skull bone from sheep are presented. The material properties are then used to investigate the propagation of ultrasonic pressure fields in the head. The ultrasound fields for three different transducers are calculated for propagation in a simulated brain/skull model. The model is constructed using speed-of-sound and mass density values of the two tissue types. The impact of the attenuation on the ultrasound fields is then examined. Finally, the relevant points drawn from these discussions are summarized. We hope to minimize the confounding effects of the skull by using sub-MHz ultrasound while maintaining the necessary temporal and spatial resolution to successfully detect injury in the brain.

Authors
Mobley, J; Kasili, PM; Norton, SJ; Vo-Dinh, T
MLA Citation
Mobley, J, Kasili, PM, Norton, SJ, and Vo-Dinh, T. "Evaluation of ultrasound techniques for brain injury detection." Proceedings of SPIE - The International Society for Optical Engineering 3253 (1998): 101-111.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3253
Publish Date
1998
Start Page
101
End Page
111
DOI
10.1117/12.308021

Development of a DNA biochip: principle and applications

This paper provides an overview of the operating principle of a DNA biochip based on integrated circuit for use in biomedical diagnostics. The device is a self-contained system with photosensors, amplifiers, discriminators and logic circuitry on board. The development and evaluation of various microchip system components of the genosensor are reviewed. Fluorescence detection of gene probes specific to DNA sequences related to pathogens such as the human immuno-deficiency virus 1 (HIV1) system illustrates the usefulness and potential of the DNA biochip technology for rapid and cost-effective medical diagnostics. Potential usefulness of the DNA biochip in clinical applications and functional genomics research is discussed.

Authors
Vo Dinh Tuan,
MLA Citation
Vo Dinh Tuan, . "Development of a DNA biochip: principle and applications." Sensors and Actuators, B: Chemical B51.1-3 (1998): 52-59. (Academic Article)
Source
manual
Published In
Sensors and Actuators, B: Chemical
Volume
B51
Issue
1-3
Publish Date
1998
Start Page
52
End Page
59
DOI
10.1016/S0925-4005(98)00182-8

Some approaches to infrared spectroscopy for detection of buried objects

Detection of buried objects presents a formidable challenge which requires many different approaches. Infrared imaging has proven its versatility in a number of applications. Recent advances in technology have opened the door for spectroscopic imaging systems which can produce images of reflectivity or emissivity as a function of two spatial dimensions and wavelength. These images have been largely unexploited for detection of buried and surface-laid landmines. Several promising opportunities exist for this application in different parts of the infrared spectrum. Variations in soil moisture content, vegetation condition, and soil composition may well be related to the presence of shallow-buried objects. In addition, polarimetric signatures appear useful in detecting man-made objects on the surface and may even help in detecting buried objects. This paper will explore both the feasibility of using infrared spectral imagery in the 1-to-2.5 and 8-to-12 micrometer infrared bands to detect surface-laid and buried objects. ©2003 Copyright SPIE - The International Society for Optical Engineering.

Authors
DiMarzio, CA; Vo-Dinh, T; Scott, HE
MLA Citation
DiMarzio, CA, Vo-Dinh, T, and Scott, HE. "Some approaches to infrared spectroscopy for detection of buried objects." Proceedings of SPIE - The International Society for Optical Engineering 3392 (1998): 158-166.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3392
Publish Date
1998
Start Page
158
End Page
166
DOI
10.1117/12.324187

Development of a multiarray biosensor for DNA diagnostics

This work involves the development and evaluation of a multiarray biosensor for DNA diagnostics. The evaluation of various system components developed for the biosensor is discussed. The DNA probes labeled with visible and near infrared (NIR) dyes are evaluated. The detection system uses a two-dimensional charge-coupled device (CCD), Examples of application of gene probes in DNA hybridization experiments and in biomedical diagnosis (detection of the p53 cancer gene) are presented to illustrate the usefulness and potential of the biosensor device.

Authors
Vo-Dinh, T; Isola, N; Alarie, JP; Landis, D; Griffin, GD; Allison, S
MLA Citation
Vo-Dinh, T, Isola, N, Alarie, JP, Landis, D, Griffin, GD, and Allison, S. "Development of a multiarray biosensor for DNA diagnostics." Instrumentation Science and Technology 26.5 (1998): 503-514.
Source
scival
Published In
Instrumentation Science and Technology
Volume
26
Issue
5
Publish Date
1998
Start Page
503
End Page
514

A new fluorescence method for the determination of ammonia

A new method is described for the determination of ammonia by exploiting the change in fluorescence intensity of the ethanolic solution of salicylaldehyde with the addition of trace amounts of aqueous ammonia solution. The method is simple, sensitive and accurate.

Authors
Pal, AA; Sau, TK; Pal, T; Vo-Dinh, T
MLA Citation
Pal, AA, Sau, TK, Pal, T, and Vo-Dinh, T. "A new fluorescence method for the determination of ammonia." Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry 37.8 (1998): 753-754.
Source
scival
Published In
Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry
Volume
37
Issue
8
Publish Date
1998
Start Page
753
End Page
754

Determination of Aluminium in Water through Formation of Fluorescent Dibenzoylmethane-Aluminium Complex and its Structure Elucidation

Dibenzoylmethane(DBM) was found to be a very good reagent for AlIII to produce a luminescent complex having the formula Al(DBM)3. The luminescence property of the complex was used to selectively quantify AlIII on filter paper substrate in the range of 5-55 ppm. The method was successfully applied to water analysis and is devoid of interferences from common anions and cations.

Authors
Pal, A; Sau, T; Pal, T; Vo-Dinh, T
MLA Citation
Pal, A, Sau, T, Pal, T, and Vo-Dinh, T. "Determination of Aluminium in Water through Formation of Fluorescent Dibenzoylmethane-Aluminium Complex and its Structure Elucidation." Journal of the Indian Chemical Society 75.2 (1998): 78-80.
Source
scival
Published In
Journal of the Indian Chemical Society
Volume
75
Issue
2
Publish Date
1998
Start Page
78
End Page
80

Erratum: (Proceedings of Biomedical Sensing and Imaging Technologies (26-27 January 1998))

Authors
Lieberman, RA; Vo-Dinh, T; Katzir, A
MLA Citation
Lieberman, RA, Vo-Dinh, T, and Katzir, A. "Erratum: (Proceedings of Biomedical Sensing and Imaging Technologies (26-27 January 1998))." Proceedings of SPIE - The International Society for Optical Engineering 3253 (1998): 289--.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
3253
Publish Date
1998
Start Page
289-

Rapid screening method for cocaine and benzoylecgonine in saliva samples

We are presenting a new method for cocaine and benzoylecgonine analysis in saliva samples based on room temperature phosphorimetry. The determination of the drugs is performed on filter paper, which is a suitable substrate for most saliva collection procedures. Extraction from the solid substrate is not necessary, since both compounds are detected on the paper substrate. Complete analysis can be performed with only a few microliters of saliva, which is an attractive feature in cases of limited sample availability. The limits of detection are estimated at the sub-ng level, which shows the feasibility of detecting cocaine and benzoylecgonine at the cut-off levels stipulated by the National Institute on Drug Abuse (300ng/ml). When compared to the existing methodology, the phosphorimetric method presents several advantages which include simplicity, short analysis time, low cost, and the viability of interfacing it with portable instrumentation for field screening applications. Copyright (C) 1998 Elsevier Science B.V.

Authors
Campiglia, AD; Vo-Dinh, T
MLA Citation
Campiglia, AD, and Vo-Dinh, T. "Rapid screening method for cocaine and benzoylecgonine in saliva samples." Analytica Chimica Acta 372.3 (1998): 349-355.
Source
scival
Published In
Analytica Chimica Acta
Volume
372
Issue
3
Publish Date
1998
Start Page
349
End Page
355
DOI
10.1016/S0003-2670(98)00317-1

Development of a DNA biochip: Principle and applications

This paper provides an overview of the operating principle of a DNA biochip based on integrated circuit for use in biomedical diagnostics. The device is a self-contained system with photosensors, amplifiers, discriminators and logic circuitry on board. The development and evaluation of various microchip system components of the genosensor are reviewed. Fluorescence detection of gene probes specific to DNA sequences related to pathogens such as the human immuno-deficiency virus 1 (HIV1) system illustrates the usefulness and potential of the DNA biochip technology for rapid and cost-effective medical diagnostics. Potential usefulness of the DNA biochip in clinical applications and functional genomics research is discussed. © 1998 Elsevier Science S.A. All rights reserved.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Development of a DNA biochip: Principle and applications." Sensors and Actuators, B: Chemical 51.1-3 (1998): 52-59.
Source
scival
Published In
Sensors and Actuators, B: Chemical
Volume
51
Issue
1-3
Publish Date
1998
Start Page
52
End Page
59

A New Photoactivated Fluorescence Detection Method for Trichloroethylene

We describe here a novel method using photoactivated fluorescence for the detection of trichloroethylene (TCE). The approach involves photoactivation by uv irradiation of TCE in the presence of a photoactivator, diphenylamine, subsequent excitation of the photoproduct complex, and detection of the luminescent photoproduct. The photoproduct exhibits new absorption fluorescent bands. Conventional fixed-wavelength excitation and synchronous luminescence (SL) are used for detection.

Authors
Pal, T; Vo-Dinh, T
MLA Citation
Pal, T, and Vo-Dinh, T. "A New Photoactivated Fluorescence Detection Method for Trichloroethylene." Journal of the Indian Chemical Society 75.8 (1998): 470-473.
Source
scival
Published In
Journal of the Indian Chemical Society
Volume
75
Issue
8
Publish Date
1998
Start Page
470
End Page
473

Surface-enhanced Raman detection of nicotinamide in vitamin tablets

Nicotinamide is analyzed quantitatively in vitamin tablets using surface-enhanced Raman scattering (SERS) on a silver-coated alumina substrate. Calibration curve of SERS signal intensity versus concentration of nicotinamide was established for quantitative analysis of this compound for detection at parts per million (ppm) level. SERS spectra of related compounds, nicotine, nicotinic acid, isonicotinic acid, and isonicotinamide were also recorded. Salient features of their spectra are compared and discussed. Copyright (C) 1998 Elsevier Science B.V.

Authors
Pal, T; Narayanan, VA; Stokes, DL; Vo-Dinh, T
MLA Citation
Pal, T, Narayanan, VA, Stokes, DL, and Vo-Dinh, T. "Surface-enhanced Raman detection of nicotinamide in vitamin tablets." Analytica Chimica Acta 368.1-2 (1998): 21-28.
Source
scival
Published In
Analytica Chimica Acta
Volume
368
Issue
1-2
Publish Date
1998
Start Page
21
End Page
28
DOI
10.1016/S0003-2670(98)00192-5

Near-field surface-enhanced Raman spectroscopy of dye molecules adsorbed on silver island films

We report the combined use of scanning near-field optical microscopy and surface-enhanced Raman scattering (SERS) to obtain spectral, spatial and chemical information of molecular adsorbates with subwavelength lateral resolution. Near-field SERS spectra of cresyl fast violet and rhodamine 6G on silver substrates are obtained with short exposure times (less than 100 s) and a signal-to-noise ratio of >20. Spectra from as few as ≈300 molecules or less than 10-2 monolayers adsorbed on about ten silver nanoparticles can be recorded using 200 nm tip apertures. For the near-field spectra, a local Raman enhancement factor of 1013 or greater can be derived from a comparison with fluorescence measurements.

Authors
Zeisel, D; Deckert, V; Zenobi, R; Vo-Dinh, T
MLA Citation
Zeisel, D, Deckert, V, Zenobi, R, and Vo-Dinh, T. "Near-field surface-enhanced Raman spectroscopy of dye molecules adsorbed on silver island films." Chemical Physics Letters 283.5-6 (1998): 381-385.
Source
scival
Published In
Chemical Physics Letters
Volume
283
Issue
5-6
Publish Date
1998
Start Page
381
End Page
385

Development of a new capillary electrophoresis-based fibre optic sensor

A new fluorescence-based fibre optic sensor is described which combines the sensitivity offered by laser-induced fluorescence with the selectivity offered by capillary electrophoresis (CE). A single optical fibre directly probes the terminus of a 5-8 cm separation capillary. The linear geometry associated with this sensor necessitates a 'single reservoir' design, thus presenting major challenges to overcome in comparison to the conventional two-reservoir configuration common to a typical laboratory setup. Some of the challenges confronted by the design features presented in this work include the reduction of gravity-driven hydrostatic flow, the ejection of electrolytic gases evolved at the detection-side electrode and the establishment a suitable compromise between detectability and separation performance. The success of such design features demonstrates the feasibility of a CE-based sensor which offers several amenities particularly useful for in situ sensing. Such attributes include selectivity, diminutive size, flexibility, reusability, high sensitivity, speed, and remote control. Detailed descriptions of sensor fabrication are included, including two variations on a general design concept. In addition, the single-fibre optical detection system is described. Separation characteristics of the new CE-based sensor are presented, highlighted by an observed separation efficiency of up to 8000 theoretical plates (for a 5 cm capillary). The separation of a three-component mixture of the laser dyes, Rhodamine 6G, fluorescein isothyocyanate and sodium fluorescein, is demonstrated.

Authors
Stokes, DL; Sepaniak, MJ; Vo-Dinh, T
MLA Citation
Stokes, DL, Sepaniak, MJ, and Vo-Dinh, T. "Development of a new capillary electrophoresis-based fibre optic sensor." Biomedical Chromatography 11.4 (July 1, 1997): 187-192.
Source
scopus
Published In
Biomedical Chromatography
Volume
11
Issue
4
Publish Date
1997
Start Page
187
End Page
192
DOI
10.1002/(SICI)1099-0801(199707)11:4<187::AID-BMC671>3.0.CO;2-0

Development of a new capillary electrophoresis-based fibre optic sensor.

A new fluorescence-based fibre optic sensor is described which combines the sensitivity offered by laser-induced fluorescence with the selectivity offered by capillary electrophoresis (CE). A single optical fibre directly probes the terminus of a 5-8 cm separation capillary. The linear geometry associated with this sensor necessitates a 'single reservoir' design, thus presenting major challenges to overcome in comparison to the conventional two-reservoir configuration common to a typical laboratory setup. Some of the challenges confronted by the design features presented in this work include the reduction of gravity-driven hydrostatic flow, the ejection of electrolytic gases evolved at the detection-side electrode and the establishment a suitable compromise between detectability and separation performance. The success of such design features demonstrates the feasibility of a CE-based sensor which offers several amenities particularly useful for in situ sensing. Such attributes include selectivity, diminutive size, flexibility, reusability, high sensitivity, speed, and remote control. Detailed descriptions of sensor fabrication are included, including two variations on a general design concept. In addition, the single-fibre optical detection system is described. Separation characteristics of the new CE-based sensor are presented, highlighted by an observed separation efficiency of up to 8000 theoretical plates (for a 5 cm capillary). The separation of a three-component mixture of the laser dyes, Rhodamine 6G, fluorescein isothyocyanate and sodium fluorescein, is demonstrated.

Authors
Stokes, DL; Sepaniak, MJ; Vo-Dinh, T
MLA Citation
Stokes, DL, Sepaniak, MJ, and Vo-Dinh, T. "Development of a new capillary electrophoresis-based fibre optic sensor." Biomed Chromatogr 11.4 (July 1997): 187-192.
PMID
9256994
Source
pubmed
Published In
Biomedical Chromatography
Volume
11
Issue
4
Publish Date
1997
Start Page
187
End Page
192
DOI
10.1002/(SICI)1099-0801(199707)11:4<187::AID-BMC671>3.0.CO;2-0

Antibody-antigen binding kinetics. A model for multivalency antibodies for large antigen systems.

This work presents a theoretical analysis of the influence of multivalency of antigen on external mass transfer-limited binding kinetics to divalent antibody for biosensor applications to polycyclic-aromatic systems. Both cases are considered wherein the antigen is in solution and the antibody is either covalently or noncovalently attached to a cylindrical fiber-optic biosensor, and the antibody is in solution and the antigen is attached to the surface. Both single-step and dual-step binding processes are considered. The rate of attachment of antigen to antibody (or vice versa) is linear for the valencies (or reaction orders) analyzed in the time frame (100 min) considered. The rate of attainment of saturation levels of antigen or antibody in solution close to the surface is very rapid (within 20 min). An increase in the valency of the antigen in solution has the effect of decreasing the order of reaction (for valency, v > or = 1). An increase in the number of steps increases the order of reaction, as expected. An increase in the valency of the antigen in solution decreases the saturation level of the antigen close to the surface and the rate of antigen attachment to the antibody on the surface for all Damkohler numbers. A decrease in the diffusional limitations decreases the effect of valency (or reaction order) on saturation levels of Cs/C0. Nondimensional plots presented in the analysis help extend the analysis to different antigen-antibody systems. An increase in the valency of the antibody in solution has the effect of increasing the order of reaction (for v > 2). The effects in this case are reverse to those described earlier. For valency greater than 2, the reaction order is dependent on the antigen valency, whether it is in solution or immobilized on the surface. The general analysis presented here should be applicable to most surface reactions that involve ligand-receptor binding wherein multiple-binding sites are involved on either the receptor or the ligand.

Authors
Sadana, A; Vo-Dinh, T
MLA Citation
Sadana, A, and Vo-Dinh, T. "Antibody-antigen binding kinetics. A model for multivalency antibodies for large antigen systems." Appl Biochem Biotechnol 67.1-2 (July 1997): 1-22.
PMID
9382485
Source
pubmed
Published In
Applied Biochemistry and Biotechnology
Volume
67
Issue
1-2
Publish Date
1997
Start Page
1
End Page
22

Alstonine as a potential fluorescent marker for tiny tumours detection and imaging

3,4,5,6,16,17-Hexadehydro-16-(methoxycarbolyl)-19α-methyl-20α-o xyohimbanium (alstonine) is a fluorescent alcaloid which is known to stain tumor cells more efficiently than normals. The interactions between alstonine and biological macromolecules were first investigated to provide the rationale for preferencial labelling. Molecular filtration and spectrofluorometric techniques with different macromolecules and isopolynucleotides have demonstrated that binding occurs only in the presence of uridyl rings. For the binding affect only the fluorescence intensity of Alstonine it can be assumed that it involves only the side chain of the fluorescent compound. The capability for preferential staining was verified in culture using SK-OV-3 cells and mt hepatocarcinoma cells as turnout cells and Mouse fibroblasts or rat liver cells as controls. Techniques of Image analysis have demonstrated the efficiency, of cellular labelling even in aggregates of rat hepatocarcinoma. These experiments lead the way to the detection of tiny minors developped on thin visceral walls (bladder,...), using a fiber optic device.

Authors
Viallet, PM; Vo-Dinh, T; Salmon, J-M; Watts, W; Rocchi, E; Isola, N; Rebillard, X
MLA Citation
Viallet, PM, Vo-Dinh, T, Salmon, J-M, Watts, W, Rocchi, E, Isola, N, and Rebillard, X. "Alstonine as a potential fluorescent marker for tiny tumours detection and imaging." Proceedings of SPIE - The International Society for Optical Engineering 2976 (1997): 332-340.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2976
Publish Date
1997
Start Page
332
End Page
340
DOI
10.1117/12.275541

Laser-induced differential fluorescence for cancer diagnosis without biopsy

An optical diagnostic procedure based on laser-induced fluorescence was developed for direct in vivo cancer diagnosis without requiring biopsy. The methodology was applied in a clinical study involving over 100 patients in order to differentiate normal tissue from malignant tumors of the esophagus. Endogenous fluorescence of normal and malignant tissues was measured directly with the use of a fiber-optic probe inserted through an endoscope. The measurements were performed in vivo during routine endoscopy. Detection of the fluorescence signal from the tissue was performed with the use of laser excitation. This report describes the differential normalized fluorescence (DNF) procedure using the amplified spectral differences between the normalized fluorescence of malignant tissue and normal mucosa. The results of this DNF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal tissue and malignant tumors for the samples investigated. Data related to various grades of Barrett's esophagus are discussed. The DNF procedure could lead to the development of a rapid and cost-effective technique for cancer diagnosis.

Authors
Vo-Dinh, T; Panjehpour, M; Overholt, BF; III, PB
MLA Citation
Vo-Dinh, T, Panjehpour, M, Overholt, BF, and III, PB. "Laser-induced differential fluorescence for cancer diagnosis without biopsy." Applied Spectroscopy 51.1 (1997): 58-63.
Source
scival
Published In
Applied Spectroscopy
Volume
51
Issue
1
Publish Date
1997
Start Page
58
End Page
63

Nomenclature, symbols, units, and their usage in spectrochemical analysis - XVI. Laser-based molecular spectroscopy for chemical analysis - Luminescence (IUPAC Recommendations 1997)

Authors
Vo Dinh, T; Velthorst, NH; Moore, DS; Schrader, B
MLA Citation
Vo Dinh, T, Velthorst, NH, Moore, DS, and Schrader, B. "Nomenclature, symbols, units, and their usage in spectrochemical analysis - XVI. Laser-based molecular spectroscopy for chemical analysis - Luminescence (IUPAC Recommendations 1997)." Pure and Applied Chemistry 69.7 (1997): 1435-. (Academic Article)
Source
manual
Published In
Pure and Applied Chemistry
Volume
69
Issue
7
Publish Date
1997
Start Page
1435

Evaluation of a Separation-Based Fiber-Optic Sensor in a Micellar Electrokinetic Capillary Chromatography Mode of Operation

A fiber-optic sensor that integrates the separation-based selectivity of capillary electrophoresis with the sensitivity afforded by laser-induced fluorescence detection is evaluated. The evaluation involves measurements of neutral analytes that are separated via the micellar electrokinetic capillary chromatography (MECC) variation of capillary electrophoresis. This separation-based fiber-optic sensor (SBFOS) employs a single-reservoir, linear configuration that presents the challenges of overcoming gravity-driven hydrostatic flow and offsetting the effects of trapped gases. Hydrostatic flow resulting from nonlevel positioning of the separation capillary is reduced through the use of a restrictor capillary. MECC separations are performed in a frontal mode of operation using relatively short separation capillaries. Studies involve measuring the magnitude and reproducibility of retention time, efficiency, and signal over applied voltages spanning 2.0-4.0 kV for test mixtures composed of three fluorescentiy derivatized amines. The relative standard deviations in retention time and bandfront height are generally less than 10%, and efficiency is in the range of 103-104 theoretical plates for an 8-cm separation capillary. The optical configuration used with the SBFOS employs a single fiber optic to deliver excitation radiation and collect fluorescence from a small region at the sensor side of the separation capillary. Linear calibration curves are generated for single-component or multicomponent samples. A disadvantage of the frontal mode of operation is the eventual displacement of the running buffer in the capillary by the sample (reagent depletion). The effects of reagent displacement are investigated by varying the compositions of samples with respect to buffer and surfactant A preliminary separation of aflatoxins G1 and G2 illustrates the potential of the SBFOS for environmentally significant sensing.

Authors
Sepaniak, MJ; Tuan, V-D; Tropina, V; Stokes, DL
MLA Citation
Sepaniak, MJ, Tuan, V-D, Tropina, V, and Stokes, DL. "Evaluation of a Separation-Based Fiber-Optic Sensor in a Micellar Electrokinetic Capillary Chromatography Mode of Operation." Analytical Chemistry 69.18 (1997): 3806-3811.
Source
scival
Published In
Analytical Chemistry
Volume
69
Issue
18
Publish Date
1997
Start Page
3806
End Page
3811

Phosphorescence imaging system using an acousto-optic tunable filter and a charge-coupled device

We are reporting for the first time the development of an imaging spectrometer for solid-surface room temperature phosphorimetry based on an acousto-optic tunable filter. A HeCd laser was employed as the excitation source, and a cooled two-dimensional charge-coupled device was used as the detector. The spectral characterization and imaging capability of the new system were evaluated with two well known phosphorescent compounds. The phosphorescence emissions of pyrene and 1,2,3,4-dibenzanthracene adsorbed on chromatography paper treated for background reduction were investigated. Thallium(I) acetate was employed as a phosphorescence enhancer. Based on the performance of the proposed instrument, several potential applications are discussed.

Authors
Campiglia, AD; Hueber, DM; Moreau, F; Vo-Dinh, T
MLA Citation
Campiglia, AD, Hueber, DM, Moreau, F, and Vo-Dinh, T. "Phosphorescence imaging system using an acousto-optic tunable filter and a charge-coupled device." Analytica Chimica Acta 346.3 (1997): 361-372.
Source
scival
Published In
Analytica Chimica Acta
Volume
346
Issue
3
Publish Date
1997
Start Page
361
End Page
372
DOI
10.1016/S0003-2670(97)90079-9

Erratum: Proceedings of Biomedical Sensing, Imaging, and Tracking Technologies II (11-13 February 1997)

Authors
Vo-Dinh, T; Luberman, RA; Vurek, GG; Katzir, A
MLA Citation
Vo-Dinh, T, Luberman, RA, Vurek, GG, and Katzir, A. "Erratum: Proceedings of Biomedical Sensing, Imaging, and Tracking Technologies II (11-13 February 1997)." Proceedings of SPIE - The International Society for Optical Engineering 2976 (1997): 379-380.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2976
Publish Date
1997
Start Page
379
End Page
380

Intracellular compartimentalization of Indo-1 and Mag-indo-1: Consequences on intracellular calcium and magnesium sensing and imaging for biomedical applications

Indo-1 and Mag-indo-1 are well known fluorescent probes which consist in two different cages of complexation covalently bound to the same fluorophor. The ionic trap of Indo-1 fit perfectly the size of the calcium ion and its sensitivity is well adapted to the basal concentration of calcium ion in the cytoplasm. Although Mag-indo-1 was designed to complex magnesium, it has been demonstrated that it is a chelator more efficient for calcium than for magnesium. Moreover it has been suggested recently that Fura 2, Indo-1, and Mag-indo-1 migth be partially located inside the membranes of intracellular organelles where the concentration of calcium is expected to be far higher than that of magnesium. All these data question again the use of the simple spectrofluorimetric methods to quantify the cytoplasmic concentration in magnesium. Our studies in solution have confirmed that Mag-indo-1 is a potent chelator for calcium and also demonstrated that the fluorescence spectrum of the calcium-bound Mag-indo-1 is quite similar to that of magnesium-bound Mag-indo-1. Experiments have been carried out with 3T3 cells to quantify the amount of Mag-indo-1 entrapped in the intracellular membranes and its consequences on the monitoring of the intracytoplasmic concentration of magnesium.

Authors
Viallet, PM; Vo-Dinh, T; Bunde, T; Pesco, J; Vigo, J; Salmon, JM
MLA Citation
Viallet, PM, Vo-Dinh, T, Bunde, T, Pesco, J, Vigo, J, and Salmon, JM. "Intracellular compartimentalization of Indo-1 and Mag-indo-1: Consequences on intracellular calcium and magnesium sensing and imaging for biomedical applications." Proceedings of SPIE - The International Society for Optical Engineering 2976 (1997): 105-116.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2976
Publish Date
1997
Start Page
105
End Page
116
DOI
10.1117/12.275519

Development of a New Capillary Electrophoresis-based Fibre Optic Sensor

Authors
Stokes, DL; Sepaniak, MJ; Vo Dinh, T
MLA Citation
Stokes, DL, Sepaniak, MJ, and Vo Dinh, T. "Development of a New Capillary Electrophoresis-based Fibre Optic Sensor." Biomedical Chromatography 11.4 (1997): 187-. (Academic Article)
Source
manual
Published In
Biomedical Chromatography
Volume
11
Issue
4
Publish Date
1997
Start Page
187
DOI
10.1002/(SICI)1099-0801(199707)11:43.0.CO;2-0

Phosphorescence imaging system using an acousto-optic filter-based charge coupled device

We are reporting for the first time the development of an imaging spectrometer for solid surface room temperature phosphorimetry based on an acousto-optic tunable filter. A He-Cd laser was employed as the excitation source, and a cooled two-dimensional charge coupled device was used as the detector. The spectral characterization and imaging capability of the new system were evaluated with two well known phosphorescent compounds. The phosphorescence emissions of pyrene and 1,2,3,4-dibenzanthracene adsorbed on chromatography paper treated for background reduction were investigated. Thallium(I) acetate was employed as a phosphorescence enhancer. Based on the performance of the proposed instrument, several potential applications are discussed.

Authors
Campiglia, AD; Moreau, F; Hueber, DM; Vo-Dinh, T
MLA Citation
Campiglia, AD, Moreau, F, Hueber, DM, and Vo-Dinh, T. "Phosphorescence imaging system using an acousto-optic filter-based charge coupled device." Analytica Chimica Acta 351.1-3 (1997): 229-239.
Source
scival
Published In
Analytica Chimica Acta
Volume
351
Issue
1-3
Publish Date
1997
Start Page
229
End Page
239
DOI
10.1016/S0003-2670(97)00236-5

Enhanced Photoactivated Luminescence of Selected Polychlorinated Biphenyl Congeners and Aroclor Mixtures

Fluorescence studies of selected polychlorinated biphenyl (PCB) congeners and Aroclor mixtures were conducted using enhanced photoactivated luminescence. Diphenylamine (DPA) was used as a photoactivator. DPA reacts with PCBs to form a fluorescent photoproduct under UV activation. The sensitivities of fluorescence detection using three different solid substrates were compared. Background studies of the substrates and DPA blanks were also conducted to determine the substrate with the best detection characteristics for enhanced photoactivated fluorescence. It was found that the Envi disk with a glass-fiber mesh and C-18-modified silica provides more analyte access for fluorescence detection, thereby providing best sensitivity. By comparison of the fluorescence from pure PCB congener-DPA complexes, the more coplanar congeners exhibited a red shift in excitation and emission as compared with the ortho-substituted nonplanar congeners. These studies may prove useful in determining trends relating fluorescence intensity and toxicity factors. © 1997 Academic Press.

Authors
Jagasia, P; Velazquez, A; Knedlik, A; Vo-Dinh, T; Oldham, PB
MLA Citation
Jagasia, P, Velazquez, A, Knedlik, A, Vo-Dinh, T, and Oldham, PB. "Enhanced Photoactivated Luminescence of Selected Polychlorinated Biphenyl Congeners and Aroclor Mixtures." Microchemical Journal 57.3 (1997): 350-360.
Source
scival
Published In
Microchemical Journal
Volume
57
Issue
3
Publish Date
1997
Start Page
350
End Page
360

Demonstration of an integrated capillary electrophoresis-laser-induced fluorescence fiber-optic sensor.

A unique integrated separation-based fiber-optic sensor for remote analysis, that incorporates capillary electrophoresis (CE) directly at the fiber sensing terminus is described for the first time. Based on laser-induced fluorescence detection, the sensor offers the potential for high sensitivity. Although the broad-band nature of fluorescence spectra limits selectivity, the high separation power of CE provides a unique dimension of selectivity, while permitting a design of diminutive size. Previously reported fluorescence-based sensors that utilize a chemical reagent phase to impart selectivity tend to be inflexible (not readily adaptable to the detection of different species) and "one-measurement-only" sensors. Conversely, the CE-based fiber-optic sensor described here is both versatile and reusable. The analysis speed and the potential for remote control are further attributes which make the system amenable to remote sensing. A "single-fiber" optical detection arrangement and a "single-reservoir" CE system with the fiber-optic probing the outlet of the separation capillary are employed. A preliminary evaluation of the separation characteristics of this CE-based sensor is presented. Highlights include an observed separation efficiency of up to 3000 theoretical plates (8 cm separation capillary) and migration time reproducibility of less than 10% for frontal mode CE separations. The potential utility of the sensor for remote analysis is demonstrated with separations involving the CE analysis of charged fluorescent dyes, CE analysis of metal complexes based on in situ complexation and micellar electrokinetic capillary chromatographic analysis of neutral fluorescent compounds.

Authors
Sepaniak, MJ; Vo-Dinh, T; Stokes, DL; Tropina, V; Dickens, JE
MLA Citation
Sepaniak, MJ, Vo-Dinh, T, Stokes, DL, Tropina, V, and Dickens, JE. "Demonstration of an integrated capillary electrophoresis-laser-induced fluorescence fiber-optic sensor." Talanta 43.11 (November 1996): 1889-1901.
PMID
18966678
Source
pubmed
Published In
Talanta
Volume
43
Issue
11
Publish Date
1996
Start Page
1889
End Page
1901
DOI
10.1016/0039-9140(96)01965-0

Fiber optic sensor for laser-induced room-temperature phosphorescence detection of polycyclic aromatic compounds.

The development of a fiber optic sensor for the analysis of polycyclic aromatic compounds based on laser-induced room-termperature phosphorimetry is reported for the first time. A pulsed nitrogen laser was used to excite phosphorescence emission from compounds imbibed on filter-paper substrates. Thallium(I) acetate (0.1 M) was used to enhance phosphorescence emission from chrysene, 1,2-benzofluorene, 7,8-benzoquinoline, phenanthridine and 5,6-benzoquinoline. Lead(II) acetate (0.5 M) was employed for the determination of fluoranthene, which showed no phosphorescence signal on paper substrates pre-treated with thallium(I) acetate. Limits of detection at the ng/ml(-1) level were estimated for all the compounds. An improvement in the limits of detection of the nitrogen heterocyclic compounds was obtained by using a low-background paper substrate. Satisfactory reproducibility of measurements was observed, varying from 6.1% (chrysene) to 11.9% (7,8-benzoquinoline). The linear behavior of the sensor response was also evaluated. Linear dynamic ranges extend over two and three orders of magnitude and show the potential of the device for the quantitative analysis of environmental pollutants.

Authors
Campiglia, AD; Vo-Dinh, T
MLA Citation
Campiglia, AD, and Vo-Dinh, T. "Fiber optic sensor for laser-induced room-temperature phosphorescence detection of polycyclic aromatic compounds." Talanta 43.10 (October 1996): 1805-1814.
PMID
18966667
Source
pubmed
Published In
Talanta
Volume
43
Issue
10
Publish Date
1996
Start Page
1805
End Page
1814
DOI
10.1016/0039-9140(96)01945-5

Endoscopic fluorescence detection of high-grade dysplasia in Barrett's esophagus.

BACKGROUND & AIMS: Early detection and treatment of esophageal cancer in Barrett's esophagus may improve patient survival if dysplasia is effectively detected at endoscopy. Typically, four-quadrant pinch biopsy specimens are taken at 2-cm intervals. This study was conducted to determine whether laser-induced fluorescence spectroscopy could be used to detect high-grade dysplasia in patients with Barrett's esophagus. METHODS: Four hundred ten-naonometer laser light was used to induce autofluorescence of Barrett's mucosa in 36 patients. The spectra were analyzed using the differential normalized fluorescence (DNF) index technique to differentiate high-grade dysplasia from either low-grade or nondysplastic mucosa. Each spectrum was classified as either premalignant or benign using two different DNF indices. RESULTS: Analysis of the fluorescence spectra from all patients collectively using the DNF intensity at 480 nm (DNF480) index showed that 96% of nondysplastic Barrett's esophagus samples were classified as benign, all low-grade dysplasia samples as benign, 90% of high-grade dysplasia samples as premalignant, and 28% of low-grade with focal high-grade dysplasia samples as premalignant. Using the two DNF indices concurrently, all patients with any high-grade dysplasia were classified correctly. CONCLUSIONS: Laser-induced fluorescence spectroscopy has great potential to detect high-grade dysplasia in Barrett's esophagus when using the DNF technique.

Authors
Panjehpour, M; Overholt, BF; Vo-Dinh, T; Haggitt, RC; Edwards, DH; Buckley, FP
MLA Citation
Panjehpour, M, Overholt, BF, Vo-Dinh, T, Haggitt, RC, Edwards, DH, and Buckley, FP. "Endoscopic fluorescence detection of high-grade dysplasia in Barrett's esophagus." Gastroenterology 111.1 (July 1996): 93-101.
PMID
8698231
Source
pubmed
Published In
Gastroenterology
Volume
111
Issue
1
Publish Date
1996
Start Page
93
End Page
101

Development of a room-temperature phosphorescence fiber-optic sensor.

The design of a new fiber-optic sensor based on solid-surface room-temperature phosphorimetry is presented for the analyses of polycyclic aromatic hydrocarbons in water samples. Analytical figures of merit are given for several compounds of environmental importance. Limits of detection at the nanograms per milliliter level were estimated for pyrene, benzo[e]pyrene, benzo[ghi]perylene, 1,2:3,4-dibenzanthracene, coronene, and 2,3-benzofluorene. The linearity of response of the phosphorescence sensor was evaluated, showing a fairly linear behavior for quantitative analysis. Finally, the feasibility of monitoring polycyclic aromatic hydrocarbons in aqueous media was illustrated by identifying pyrene in a contaminated groundwater sample.

Authors
Campiglia, AD; Alarie, JP; Vo-Dinh, T
MLA Citation
Campiglia, AD, Alarie, JP, and Vo-Dinh, T. "Development of a room-temperature phosphorescence fiber-optic sensor." Anal Chem 68.9 (May 1, 1996): 1599-1604.
PMID
21619126
Source
pubmed
Published In
Analytical Chemistry
Volume
68
Issue
9
Publish Date
1996
Start Page
1599
End Page
1604
DOI
10.1021/ac951035y

Antigen-antibody diffusion-limited binding kinetics for biosensors: A fractal analysis

A fractal analysis is presented for the binding of benzopyrene-tetraol (BPT) in solution to anti-BPT attached to diol silica beads in a fiber-optic antibody-based biosensor. The binding rate coefficient, k1, and the fractal dimension, Df, both increase as the BPT concentration in solution increases from 3 × 10-9 to 1.59 × 10-8 M. Predictive relations for k1 (Sets 1 and 2) and for Df (Set 2 only) as a function of BPT concentration are provided. These relations fit the calculated k1 and Df values in the BPT concentration range reasonably well. Fractal analysis data seem to indicate that an increase in the BPT concentration in solution increases the 'roughness' or the state of disorder on the fiber-optic biosensor surface. Fractal analysis data provide novel physical insights into the reactions occurring on the fiber-optic biosensor surface and should assist in the design of fiber-optic biosensors.

Authors
Sadana, A; Alarie, JP; Vo-Dinh, T
MLA Citation
Sadana, A, Alarie, JP, and Vo-Dinh, T. "Antigen-antibody diffusion-limited binding kinetics for biosensors: A fractal analysis." Sensors and Actuators, B: Chemical 32.3 (1996): 195-201.
Source
scival
Published In
Sensors and Actuators, B: Chemical
Volume
32
Issue
3
Publish Date
1996
Start Page
195
End Page
201
DOI
10.1016/S0925-4005(97)80029-9

Spectroscopy commissions of the International Union of Pure and Applied Chemistry

All chemists have heard of the International Union of Pure and Applied Chemistry, or IUPAC as it is usually called. Most chemists have regularly made use of the work of IUPAC, even if did not realize that they were doing so. Infrared spectroscopists have depended for years on the IUPAC wavenumber standards to make their spectral data transferable between laboratories, or even transferable across temperature changes in the same laboratory. But few chemists or spectroscopists know much about IUPAC. The purpose of the article is to tell the reader about IUPAC and its spectroscopy commissions. IUPAC was founded in 1919 as a voluntary, nongovernmental, nonprofit association of National Adhering Organizations. In 1995 IUPAC had 40 Member Countries, 14 Observer Countries, 30 Associated Organizations, and approximately 160 Company Associates worldwide. Each country interacts with IUPAC through its National Adhering Organization.

Authors
Bertie, JE; Vo-Dinh, T
MLA Citation
Bertie, JE, and Vo-Dinh, T. "Spectroscopy commissions of the International Union of Pure and Applied Chemistry." Applied Spectroscopy 50.4 (1996): 12-20.
Source
scival
Published In
Applied Spectroscopy
Volume
50
Issue
4
Publish Date
1996
Start Page
12
End Page
20

Remote spectral imaging system (RSIS) based on an acousto-optic tunable filter (AOTF)

This paper describes a new remote spectral imaging system (RSIS) based on an acousto-optic tunable filter (AOTF) capable of remote sensing using an imaging fiberoptic probe (IFP). A two-dimensional charge coupled device (CCD) was used as a detector. The AOTF was used as a wavelength selector. Unlike a tunable grating or prism based monochromator, the tunable filter has no moving parts, and it can be rapidly tuned to any wavelength in its operating range. The large aperture of the AOTF and its high spatial resolution allowed the optical image from an IFP to be recorded by a CCD. These characteristics, combined with their small size, make AOTF's important new alternatives to conventional monochromators, especially for spectral multisensing and imaging. A prototype RSIS system, using both IFP and AOTF, was developed and its feasibility for spectral imaging was demonstrated.

Authors
Moreau, F; Hueber, DM; Vo-Dinh, T
MLA Citation
Moreau, F, Hueber, DM, and Vo-Dinh, T. "Remote spectral imaging system (RSIS) based on an acousto-optic tunable filter (AOTF)." Instrumentation Science and Technology 24.3 (1996): 179-193.
Source
scival
Published In
Instrumentation Science and Technology
Volume
24
Issue
3
Publish Date
1996
Start Page
179
End Page
193

Fiber-optic remote multisensor system based on an Acousto-Optic Tunable Filter (AOTF)

This paper describes a new fiber-optic multisensor based on an acousto-optic tunable filter (AOTF) and capable of remote sensing using a multioptical fiber array (MOFA). A two-dimensional charge-coupled device (CCD) was used as a detector, and the AOTF was used as a wavelength selector. Unlike a tunable grating or prism-based monochromator, an AOTF has no moving parts, and an AOTF can be rapidly tuned to any wavelength in its operating range within microseconds. The large aperture of the AOTF allows the optical signal from over 100 fiber-optic sensors to be measured simultaneously. These characteristics, combined with their small size, make AOTFs an important new alternative to conventional monochromators, especially for spectral multisensing and imaging. A prototype fiber-optic multisensor system has been developed, and its feasibility for simultaneous detection of molecular luminescence signal via fiber-optic probes is demonstrated.

Authors
Moreau, F; Moreau, SM; Hueber, DM; Vo-Dinh, T
MLA Citation
Moreau, F, Moreau, SM, Hueber, DM, and Vo-Dinh, T. "Fiber-optic remote multisensor system based on an Acousto-Optic Tunable Filter (AOTF)." Applied Spectroscopy 50.10 (1996): 1295-1300.
Source
scival
Published In
Applied Spectroscopy
Volume
50
Issue
10
Publish Date
1996
Start Page
1295
End Page
1300

Vibrational spectra of the industrial dyes cresyl fast violet, phloxine B and saffron. Intensity studies by surface-enhanced Raman spectroscopy

The vibrational spectra, Fourier transform Raman, Fourier transform infrared, and surface-enhanced Raman scattering (SERS) spectra of the dyes cresyl fast violet, phloxine B, and saffron have been recorded and analyzed. The intensity of the intense SERS peak of the aromatic ring vibration at 1495 cm-1 in phloxine B, and the intense 592 cm-1 peak due to CCC and CMC in plane skeletal deformation frequency has been studied as a function of the analyte concentration of these two dyes. Quantitative calibration curves for cresyl fast violet and phloxine B are presented. Limits of detection of these two dyes by SERS are reported. All the three dyes give fluorescence-free SERS spectra. © Elsevier.

Authors
Narayanan, VA; Stokes, DL; Vo-Dinh, T
MLA Citation
Narayanan, VA, Stokes, DL, and Vo-Dinh, T. "Vibrational spectra of the industrial dyes cresyl fast violet, phloxine B and saffron. Intensity studies by surface-enhanced Raman spectroscopy." Analusis 24.1 (1996): 1-5.
Source
scival
Published In
Analusis
Volume
24
Issue
1
Publish Date
1996
Start Page
1
End Page
5

Development of a genosensor for Mycobacterium tuberculosis

This work involves the development of a fiberoptic genosensor for the detection of Mycobacterium tuberculosis. A rapid and sensitive non-radioactive method for the detection of Mycobacterium is described. This method involves polymerase chain reaction (PCR) amplification of the target DNA utilizing gene specific primers labelled with fluorescein at the 5' end and hybridization of the amplified product to a species specific oligonucleotide probe sequence covalently linked to the end of a fiber. The fluorescent hybridization products are detected by laser induced fluorescence using an argon laser (488 nm).

Authors
Isola, NR; Alarie, JP; Griffin, GD; Vo-Dinh, T
MLA Citation
Isola, NR, Alarie, JP, Griffin, GD, and Vo-Dinh, T. "Development of a genosensor for Mycobacterium tuberculosis." Proceedings of SPIE - The International Society for Optical Engineering 2676 (1996): 228-240.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2676
Publish Date
1996
Start Page
228
End Page
240

Determination of Enhancement Factors for Surface-Enhanced FT-Raman Spectroscopy on Gold and Silver Surfaces

The combination of surface-enhanced Raman spectroscopy (SERS) with near-infrared (NIR) excitation should be of considerable benefit for trace detection of biological and environmental samples. Enhancement factors for SERS of p-aminobenzoic acid (PABA) on silver/alumina, silver island, gold/alumina and gold island surfaces were determined using unenhanced FT-Raman spectra of PABA on glass and glass/alumina surfaces as references. The silver/alumina substrate provided the greatest enhancement factor, followed by silver island, gold/alumina and gold island substrates, respectively. An enhancement factor in excess of 106 for PABA on a silver/alumina substrate compares favourably with literature reports of similar systems at shorter wavelengths.

Authors
Ibrahim, A; Oldham, PB; Stokes, DL; Vo-Dinh, T
MLA Citation
Ibrahim, A, Oldham, PB, Stokes, DL, and Vo-Dinh, T. "Determination of Enhancement Factors for Surface-Enhanced FT-Raman Spectroscopy on Gold and Silver Surfaces." Journal of Raman Spectroscopy 27.12 (1996): 887-891.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
27
Issue
12
Publish Date
1996
Start Page
887
End Page
891

Surface-enhanced Raman detection of nerve agent simulant (DMMP and DIMP) vapor on electrochemically prepared silver oxide substrates

Surface-enhanced Raman scattering (SERS) spectra of the chemical nerve agent simulants dimethyl methylphosphonate (DMMP) and diisopropyl methylphosphonate (DIMP) were obtained in the vapor phase. The spectra obtained demonstrate the possibility of detecting these nerve agent species in the vapor phase using electrochemically roughened silver oxide substrates prepared from silver foil.

Authors
Taranenko, N; Alarie, J-P; Stokes, DL; Vo-Dinh, T
MLA Citation
Taranenko, N, Alarie, J-P, Stokes, DL, and Vo-Dinh, T. "Surface-enhanced Raman detection of nerve agent simulant (DMMP and DIMP) vapor on electrochemically prepared silver oxide substrates." Journal of Raman Spectroscopy 27.5 (1996): 379-384.
Source
scival
Published In
Journal of Raman Spectroscopy
Volume
27
Issue
5
Publish Date
1996
Start Page
379
End Page
384

Laser-induced solid-surface room-temperature phosphorimetry of polycyclic aromatic hydrocarbons

Laser-induced solid-surface room-temperature phosphorimetry (SSRTP) has been employed for the detection of polycyclic aromatic hydrocarbons. A nitrogen-pumped laser and a dye laser were used as excitation sources. The effects of sample volume, laser irradiation, and background reduction treatment on the precision and sensitivity of the method were studied. With the use of thallium(I) acetate as a phosphorescence enhancer, picogram limits of detection were estimated for phenanthrene, pyrene, benzo[g,h,i]perylene, chrysene, coronene, and 1,2-benzofluorene. The study demonstrates that laser excitation can improve the sensitivity of SSRTP by up to three orders of magnitude.

Authors
Campiglia, AD; Hueber, DM; Vo-Dinh, T
MLA Citation
Campiglia, AD, Hueber, DM, and Vo-Dinh, T. "Laser-induced solid-surface room-temperature phosphorimetry of polycyclic aromatic hydrocarbons." Applied Spectroscopy 50.2 (1996): 252-256.
Source
scival
Published In
Applied Spectroscopy
Volume
50
Issue
2
Publish Date
1996
Start Page
252
End Page
256

Discrimination between tumour and normal cells by staining with 3,4,5,6,16,17-hexadehydro-16-(methoxycarbonyl)-19α-methyl-20α -oxayohimbanium: The uracil ring as a target for the specific interaction between RNA(s) and the fluorescent probe

3,4,5,6,16,17-Hexadehydro-16-(methoxycarbonyl)-19α-methyl-20α -oxayohimbanium (Alstonine) is a fluorescent alcaloid which has been known to stain tumour cells more efficiently than normal ones. In this paper the spectral properties of Alstonine were first investigated and its capability for preferential staining of tumour cells verified in culture using SK-OV-3 cells as tumour cells and Mouse 3T3 fibroblasts as controls. Then interactions between Alstonine and biological macromolecules were investigated to provide the rationale for preferential labelling. Molecular filtration techniques have demonstrated that binding occurs only with RNA molecules. Similar experiments were performed with different isopolynucleotides to find an explanation for that specificity. They provide evidence that binding occurs only in the presence of a uridyl ring. This is consistent with the specificity of the linkage to RNA. As the linkage of Alstonine with RNA did not induce any shift or obvious change in the intensity of its fluorescence spectrum, it is concluded that the binding might involve the side chain of the fluorescent compound.

Authors
Salmon, JM; Yassine, M; Vo-Dinh, T; Isola, NR; Rebillard, X; Viallet, P
MLA Citation
Salmon, JM, Yassine, M, Vo-Dinh, T, Isola, NR, Rebillard, X, and Viallet, P. "Discrimination between tumour and normal cells by staining with 3,4,5,6,16,17-hexadehydro-16-(methoxycarbonyl)-19α-methyl-20α -oxayohimbanium: The uracil ring as a target for the specific interaction between RNA(s) and the fluorescent probe." Anticancer Research 16.4 A (1996): 1881-1886.
Source
scival
Published In
Anticancer research
Volume
16
Issue
4 A
Publish Date
1996
Start Page
1881
End Page
1886

Laser-induced fluorescence detection of dysplasia in Barrett's esophagus

A study was conducted to determine whether laser-induced fluorescence could detect high grade dysplasia in Barrett's esophagus. Four-hundred-ten nm laser light was used to induce autofluorescence of Barrett's mucosa in 36 patients during routine endoscopy. The spectra were analyzed using the Differential Normalized Fluorescence (DNF) Index technique to differentiate high grade dysplasia from either low grade or non-dysplastic mucosa. Each spectrum was classified as either premalignant or benign using two different DNF indices. Analyzing the fluorescence spectra from all patients using one DNF Index, 96% of non-dysplastic Barrett's samples classified as benign tissue. All low grade dysplasia samples classified as benign. Ninety percent of high grade dysplasia samples classified as premalignant. Twenty-eight percent of mixed low grade/focal high grade dysplasia samples classified as premalignant. In summary, high grade dysplasia in Barrett's esophagus patients can be detected by endoscopic laser-induced fluorescence spectroscopy using differential normalized fluorescence technique. ©2004 Copyright SPIE - The International Society for Optical Engineering.

Authors
Panjehpour, M; Overholt, BF; Vo-Dinh, T; Edwards, DH; III, PFB; DeCosta, JF; Haggitt, RC
MLA Citation
Panjehpour, M, Overholt, BF, Vo-Dinh, T, Edwards, DH, III, PFB, DeCosta, JF, and Haggitt, RC. "Laser-induced fluorescence detection of dysplasia in Barrett's esophagus." Proceedings of SPIE - The International Society for Optical Engineering 2679 (1996): 16-25.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2679
Publish Date
1996
Start Page
16
End Page
25
DOI
10.1117/12.237584

Laser-excited synchronous fluorescence system for the analysis of polycyclic aromatic compounds

We describe a laser-based synchronous luminescence (LSL) monitor developed for the detection of polycyclic aromatic compounds (PAC). With LSL the amount of sample pre-treatment can often be reduced and both the selectivity and sensitivity of the analysis can be increased by the high power and narrow profile of a laser source. A small, portable, pulsed dye laser was used in this study. The instrument and its application to the determination of PACs will be described. For comparison purposes, measurements using conventional synchronous luminescence of mixtures are also discussed.

Authors
Vo-Dinh, T; Viallet, P; Olmo, IMD; Hueber, D; Stevenson, CL; Campiglia, AD
MLA Citation
Vo-Dinh, T, Viallet, P, Olmo, IMD, Hueber, D, Stevenson, CL, and Campiglia, AD. "Laser-excited synchronous fluorescence system for the analysis of polycyclic aromatic compounds." Polycyclic Aromatic Compounds 9.1-4 (1996): 265-272.
Source
scival
Published In
Polycyclic Aromatic Compounds
Volume
9
Issue
1-4
Publish Date
1996
Start Page
265
End Page
272

Laser-induced fluorescence spectroscopy: Somewhere over the rainbow

Authors
Dam, JV; Panjehpour, M; Overholt, BF; Vo-Dinh, T
MLA Citation
Dam, JV, Panjehpour, M, Overholt, BF, and Vo-Dinh, T. "Laser-induced fluorescence spectroscopy: Somewhere over the rainbow." Gastroenterology 110.2 (1996): 643-645.
PMID
8566617
Source
scival
Published In
Gastroenterology
Volume
110
Issue
2
Publish Date
1996
Start Page
643
End Page
645
DOI
10.1053/gast.1996.v110.agast960643

Antibody-based submicron biosensor for Benzo[a]pyrene DNA adduct

Fiberoptic-based sensors have been developed for monitoring human exposure and health effects associated with polycyclic aromatic compounds such as benzo[a]pyrene. These sensors take advantage of the physical properties of optical fibers including their relatively small size, remote sensing capabilities, and their inertness to electrical interferences. The recent development of submicron-sized optical fibers provides an opportunity to further reduce the size of fiberoptic-based sensors for application in submicron environments. This paper describes the development of an antibody based submicron fiber biosensor. The antibody-based biosensor is more selective and sensitive than a nonantibody sensor and has an absolute detection limit of ≈300 zeptomoles (10-21 moles) for benzo pyrene tetrol, a product of the benzo[a]pyrene DNA adduct. This submicron-size biosensor could provide a useful tool for measurements of toxic chemicals and related metabolites in sub cellularsize environments.

Authors
Alarie, JP; Vo-Dinh, T
MLA Citation
Alarie, JP, and Vo-Dinh, T. "Antibody-based submicron biosensor for Benzo[a]pyrene DNA adduct." Polycyclic Aromatic Compounds 8.1 (1996): 45-52.
Source
scival
Published In
Polycyclic Aromatic Compounds
Volume
8
Issue
1
Publish Date
1996
Start Page
45
End Page
52

Analysis of polycyclic aromatic compounds in soil samples using laser-induced phosphorimetry

The analysis and spectral characteristics of several polycyclic aromatic hydrocarbons (PAHs) have been investigated by Laser-Induced Solid-Surface Room Temperature Phosphorimetry (LI-SSRTP). These PAHs included phenanthrene, chrysene, 1,2 benzofluorene, 2,3 benzofluorene, pyrene, coronene, 1,2,3,4 dibenzanthracene, benzo(a)pyrene, benzo(e)pyrene, and benzo(g,h,i)perylene. A nitrogen laser was employed as the excitation source at 337 nm. Filter paper treated with UV irradiation for background reduction was used as the solid substrate. Thallium(I)acetate was employed as a phosphorescence enhancer. Absolute limits of detection in the picogram level were obtained for all the PAHs, improving SSRTP levels of detection by three orders of magnitude. Finally, the proposed method was tested with a PAH contaminated soil sample. Detection of several PAHs at the nanogram level was easily performed, showing the potential of LI-SSRTP to the analysis of samples of environmental concern.

Authors
Campiglia, AD; Hueber, DM; Vo-Dinh, T
MLA Citation
Campiglia, AD, Hueber, DM, and Vo-Dinh, T. "Analysis of polycyclic aromatic compounds in soil samples using laser-induced phosphorimetry." Polycyclic Aromatic Compounds 8.2-3 (1996): 117-128.
Source
scival
Published In
Polycyclic Aromatic Compounds
Volume
8
Issue
2-3
Publish Date
1996
Start Page
117
End Page
128

Detection of colon malignancy using differential normalized fluorescence

Laser-induced fluorescence was used for direct in-vivo diagnosis of colon malignancy without requiring biopsy. The methodology was applied in a clinical study in order to differentiate adenomatous polyps from hyperplastic polyps in the colon. The measurements were performed in vivo during routine colonoscopy. Detection of the fluorescence signal from the tissue was performed using laser excitation. This report describes the differential normalized fluorescence (DNF) procedure using the amplified spectral differences between the normalized fluorescence of polyps and normal tissue. Data related to various grades of pathology of colonic tissues are discussed. In this preliminary study, the DNF procedure provides a general trend which corresponds to severity of dysplasia associated with colon malignancy. ©2004 Copyright SPIE - The International Society for Optical Engineering.

Authors
Vo-Dinh, T; Panjehpour, M; Overholt, BF; III, PFB; Edwards, DH
MLA Citation
Vo-Dinh, T, Panjehpour, M, Overholt, BF, III, PFB, and Edwards, DH. "Detection of colon malignancy using differential normalized fluorescence." Proceedings of SPIE - The International Society for Optical Engineering 2679 (1996): 26-33.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2679
Publish Date
1996
Start Page
26
End Page
33
DOI
10.1117/12.237592

Spectroscopic diagnosis of esophageal cancer: new classification model, improved measurement system.

Laser-induced fluorescence spectroscopy was used to measure fluorescence emission of normal and malignant tissue during endoscopy in patients with esophageal cancer and volunteers with normal esophagus. The spectroscopy system consisted of a nitrogen-pumped dye-laser tuned at 410 nm for excitation source, an optical multichannel analyzer for spectrum analysis, and a fiberoptic probe designed for both the delivery of excitation light and the collection of fluorescence emission from tissue. The fluorescence lineshape of each spectrum was determined and sampled at 15-nm intervals from 430 to 716 nm. A calibration set of spectra from normal and malignant spectra was selected. Using stepwise discriminate analysis, significant wavelengths that separated normal from malignant spectra were selected. The intensities at these wavelengths were used to formulate a classification model using linear discriminate analysis. The model was then used to classify additional tissue spectra from 26 malignant and 108 normal sites into either normal or malignant spectra. A sensitivity of 100% and specificity of 98% were obtained.

Authors
Panjehpour, M; Overholt, BF; Schmidhammer, JL; Farris, C; Buckley, PF; Vo-Dinh, T
MLA Citation
Panjehpour, M, Overholt, BF, Schmidhammer, JL, Farris, C, Buckley, PF, and Vo-Dinh, T. "Spectroscopic diagnosis of esophageal cancer: new classification model, improved measurement system." Gastrointest Endosc 41.6 (June 1995): 577-581.
PMID
7672552
Source
pubmed
Published In
Gastrointestinal Endoscopy
Volume
41
Issue
6
Publish Date
1995
Start Page
577
End Page
581

Nomenclature, Symbols, Units and their Usage in Spectrochemical Analysis—Xi detection of radiation

This report is 11th in the series on Spectrochemical Methods of Analysis issued by IUPAC Commission V.4. It is concerned with Radiation Detection as used in analytical atomic and molecular emission, absorption, and fluorescence spectroscopy in the X-ray and optical wavelength region (i.e.from 10 pm to 1 mm). The present report has five main sections: terms relating to (a) fundamental properties of detectors, (b) thermal detectors, (c) photo-emissive detectors, (d) semiconductor detectors, and (e) spatially resolving detectors. Although still of considerable importance, photographic emulsions are not included. © 1995 IUPAC

Authors
Laqua, K; Schrader, B; Hoffmann, GG; Moore, DS; Vo-Dinh, T
MLA Citation
Laqua, K, Schrader, B, Hoffmann, GG, Moore, DS, and Vo-Dinh, T. "Nomenclature, Symbols, Units and their Usage in Spectrochemical Analysis—Xi detection of radiation." Pure and Applied Chemistry 67.10 (January 1, 1995): 1745-1760.
Source
scopus
Published In
Pure and applied chemistry. Chimie pure et appliquee
Volume
67
Issue
10
Publish Date
1995
Start Page
1745
End Page
1760
DOI
10.1351/pac199567101745

Laser-excited sychronous flourescence spectrometer for benzo(a)pyrene

A laser-based synchronous scanning fluorimeter has been developed for the detection of polycyclic aromatic hydrocarbons (PAHs). Although extensive sample cleanup and separation are usually required, fluorescence has long been used for the determination of PAHs. The amount of sample pre-treatment can often be reduced when synchronous fluorescence (SF) is used, and the sensitivity of SF can be increased by the high power and narrow profile of a laser source. A small, portable, pulsed dye laser was used in this study. The instrument and its application to the determination of the carcinogen, benzo(a)pyrene, are described.

Authors
Hueber, DM; Iruela, MDO; Stevenson, CL; Vo-Dinh, T
MLA Citation
Hueber, DM, Iruela, MDO, Stevenson, CL, and Vo-Dinh, T. "Laser-excited sychronous flourescence spectrometer for benzo(a)pyrene." Proceedings of SPIE - The International Society for Optical Engineering 2504 (1995): 539-545.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2504
Publish Date
1995
Start Page
539
End Page
545

Selective surface-enhanced Raman spectroscopy using a polymer-coated substrate

The polymer, poly(vinylpyrrolidone), is investigated as a potential coating for alumina-based surface-enhanced Raman scattering (SERS) substrates. Description for dipcoating alumina substrates with a 5% (w/v) methanolic solution of the polymer is included. Using these polymer-coated substrates, various compounds, including monocyclic aromatic compounds with hydroxyl, carboxyl, and various nitrogen-based functional groups, are detected. Intensity of SERS signals from the polymer-coated substrates in comparison to that of SERS signals from uncoated substrates is demonstrated to be a function of the analyte permeability to the polymer coating. Different enhancement factors are reported for various compounds, such as benzoic acid, isonicotinic acid, and 2,4-dinitrophenol, thus indicating some enhancement selectivity of the polymer coating to various analytes. Using benzoic acid as a test compound, various coating procedures (horizontal and vertical dipping procedures) have been evaluated. The poly(vinylpyrrolidone)-coated substrate is shown to yield a relative standard deviation in SERS signal intensity of ∼20%. The potential of the polymer-coated substrate as a selective detection probe is illustrated using the analyses of binary mixtures. Finally, the advantages of the polymer coating for protecting the SERS-active layer are also discussed.

Authors
Pal, A; Stokes, DL; Alarie, JP; Vo-Dinh, T
MLA Citation
Pal, A, Stokes, DL, Alarie, JP, and Vo-Dinh, T. "Selective surface-enhanced Raman spectroscopy using a polymer-coated substrate." Analytical Chemistry 67.18 (1995): 3154-3159.
Source
scival
Published In
Analytical Chemistry
Volume
67
Issue
18
Publish Date
1995
Start Page
3154
End Page
3159

Field screening of polycyclic hydrocarbons contamination in soil using a portable synchronous scanning spectrofluorometer

Polycyclic aromatic hydrocarbons (PAH) contamination is a considerable problem at various hazardous waste sites. Sources of PAH contamination include incomplete combustion processes, wood preservatives, and the fuel industry. The development of rapid, cost-effective field screening techniques to qualitate or quantitate potential PAH contamination could result in improved remediation efficiency. We have recently developed a portable spectrofluorometer for screening potential PAH contaminants at field sites using the synchronous fluorescence approach. Synchronous fluorescence differs from the more conventional excitation or emission fluorescence as both monochromators are scanned simultaneously with a constant wavelength offset (Δλ) between the two. The portable spectrofluorometer was developed at Oak Ridge National Laboratory (ORNL) for the U.S. Environmental Protection Agency (EPA), National Exposure Research Laboratory, and recently field tested at the American Creosote Works Superfund Site in Jackson, Tennessee. In this paper, the portable spectrofluorometer was used to field screen several contaminated soil areas located at the Morristown Industrial Site in Morristown, Tennessee using the synchronous fluorescence technique. An attempt to quantify PAH contamination was performed using the NIST 1647a priority pollutant standard to generate a calibration curve. Representative samples were subsequently related to the results obtained from standard laboratory measurements.

Authors
Alarie, JP; Watts, W; Miller, D; Hyfantis, G; Peeler, G; Engelmann, WH; Vo-Dinh, T
MLA Citation
Alarie, JP, Watts, W, Miller, D, Hyfantis, G, Peeler, G, Engelmann, WH, and Vo-Dinh, T. "Field screening of polycyclic hydrocarbons contamination in soil using a portable synchronous scanning spectrofluorometer." Proceedings of SPIE - The International Society for Optical Engineering 2504 (1995): 512-519.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2504
Publish Date
1995
Start Page
512
End Page
519

Capillary electrophoresis-laser fluorometry instrumentation for the facile optimization of DNA separations using in situ size-selective gradients and adjustable detection zone

The construction and evaluation of a capillary electrophoresis instrument for the facile optimization of DNA separations is described herein. This instrumentation allows for convenient translation of the detection zone with little loss in detectability. Changing the effective capillary length is shown to be important when complete resolution of specified DNA fragments in a sample, in the minimum time, is desired. Efficiency is found to decrease with column length in accordance with limits imposed by axial diffusion. However, complete resolution of the fragments in a OX-174-HeaIII digest is accomplished in 155 s at moderate field strengths and an effective capillary length of 15 cm. It is also demonstrated that in situ gradients can be established using this instrumentation. The general Chromatographic elution problem is addressed with gradients, resulting in further improvements in separation performance relative to isocratic separations.

Authors
Clark, BK; Vo-Dinh, T; Sepaniak, MJ
MLA Citation
Clark, BK, Vo-Dinh, T, and Sepaniak, MJ. "Capillary electrophoresis-laser fluorometry instrumentation for the facile optimization of DNA separations using in situ size-selective gradients and adjustable detection zone." Analytical Chemistry 67.3 (1995): 680-683.
Source
scival
Published In
Analytical Chemistry
Volume
67
Issue
3
Publish Date
1995
Start Page
680
End Page
683

Surface-enhanced Raman fiber optic sensors for remote monitoring

A new sensor design for remote surface-enhanced Raman scattering (SERS) measurements has been developed for environmental applications. The design features the modification of an optical fiber using layers of alumina microparticles and silver coatings for inducing the SERS effect at the sensing probe. A single fiber caries both the laser excitation and the SERS signal radiation, keeping optical parameters at the remote tip simple and consistent. The small tip size achievable with this configuration also demonstrates potential of this new design as a microsensor for in-situ measurement in microenvironments. Details of sensor tip fabrication and optical system design are described. SERS spectra of aqueous environmental samples acquired in-situ using the SERS sensor are also presented to illustrate the effectiveness of the SERS sensor.

Authors
Stokes, DL; Alarie, JP; Vo-Dinh, T
MLA Citation
Stokes, DL, Alarie, JP, and Vo-Dinh, T. "Surface-enhanced Raman fiber optic sensors for remote monitoring." Proceedings of SPIE - The International Society for Optical Engineering 2504 (1995): 552-558.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2504
Publish Date
1995
Start Page
552
End Page
558

Fractal analysis for the development of chemical sensors for environmental monitoring

A fractal analysis is presented for the binding of pyrene in solution to beta-cyclodextrin attached to a fiberoptic chemical sensor. The specific (k 1) and the non-specific binding rate (k ns) coefficients and the fractal dimension, D f (specific binding case only) both tend to increase as the pyrene concentration in solution increases from 12.4 to 124 ng/mL. Predictive relations for the binding rate coefficient (specific as well as non-specific binding) and for D f (specific binding case only) as a function of pyrene concentration are provided. These relations fit the calculated k 1 and D f values in the pyrene concentration range reasonably well. The fractal analysis provides novel physical insights into the reactions occurring on the fiberoptic chemical surface and should assist in the design of fiberoptic chemical sensors.

Authors
Sadana, A; Vo-Dinh, T
MLA Citation
Sadana, A, and Vo-Dinh, T. "Fractal analysis for the development of chemical sensors for environmental monitoring." Proceedings of SPIE - The International Society for Optical Engineering 2504 (1995): 480-485.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2504
Publish Date
1995
Start Page
480
End Page
485

Fast scanning synchronous luminescence spectrometer based on acousto-optic tunable filters

A new luminescence spectrometer based on quartz-collinear acousto-optic tunable filters (AOTFs) and capable of synchronous scanning is described. An acousto-optic tunable filter is an electronically tunable optical bandpass filter. Unlike a tunable grating monochromator, an AOTF has no moving mechanical parts, and an AOTF can be tuned to any wavelength within its operating range in microseconds. These characteristics, combined with the small size of these devices, make AOTFs an important new alternative to conventional monochromators, especially for portable instrumentation. The relevant performance of the AOTFs (efficiency, bandwidth, rejection, etc.) is compared with that of typical small-grating monochromator

Authors
Hueber, DM; Stevenson, CL; Vo Dinh, T
MLA Citation
Hueber, DM, Stevenson, CL, and Vo Dinh, T. "Fast scanning synchronous luminescence spectrometer based on acousto-optic tunable filters." Appl. Spectrosc. (USA) 49.11 (1995): 1624-1631. (Academic Article)
Source
manual
Published In
Appl. Spectrosc. (USA)
Volume
49
Issue
11
Publish Date
1995
Start Page
1624
End Page
1631

Development of gene-probe-based biosensors for environmental analysis

This work involves the design and development of species specific gene (DNA) probes designed to detect Pseudomonas species. A non radioactive detection system for DNA was designed to detect the presence of these microbes in environmental samples for biomonitoring applications. The details of the methodology and their applicability for various environmental analyses is discussed below.

Authors
Isola, NR; Burlage, RB; Landis, DA; Griffin, GD; Vo-Dinh, T
MLA Citation
Isola, NR, Burlage, RB, Landis, DA, Griffin, GD, and Vo-Dinh, T. "Development of gene-probe-based biosensors for environmental analysis." Proceedings of SPIE - The International Society for Optical Engineering 2504 (1995): 506-511.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
2504
Publish Date
1995
Start Page
506
End Page
511

SERS chemical sensors and biosensors: new tools for environmental and biological analysis

This paper describes recent advances in chemical sensors and biosensors based on surface-enhanced Raman scattering (SERS) detection. The SERS-active probes involve silver-coated microstructured substrates designed to amplify the Raman signals of adsorbed molecules and to detect trace chemicals in liquid as well as vapor samples. The development and application of several SERS devices such as a fiber-optic remote sensor and a vapor dosimeter are described. The results illustrate the different uses of the SERS method for the identification and quantification of important environmental and biological compounds.

Authors
Vo Dinh Tuan,
MLA Citation
Vo Dinh Tuan, . "SERS chemical sensors and biosensors: new tools for environmental and biological analysis." Sensors and Actuators, B: Chemical B29.1-3 (1995): 183-189. (Academic Article)
Source
manual
Published In
Sensors and Actuators, B: Chemical
Volume
B29
Issue
1-3
Publish Date
1995
Start Page
183
End Page
189
DOI
10.1016/0925-4005(95)01681-3

Nomenclature, symbols, units and their usage in spectrochemical analysis-XV. Laser-based molecular spectroscopy for chemical analysis-laser fundamentals (IUPAC Recommendations 1995)

Authors
Moore, DS; Vo Dinh, T; Velthorst, NH; Schrader, B
MLA Citation
Moore, DS, Vo Dinh, T, Velthorst, NH, and Schrader, B. "Nomenclature, symbols, units and their usage in spectrochemical analysis-XV. Laser-based molecular spectroscopy for chemical analysis-laser fundamentals (IUPAC Recommendations 1995)." Pure and Applied Chemistry 67.11 (1995): 1913-. (Academic Article)
Source
manual
Published In
Pure and Applied Chemistry
Volume
67
Issue
11
Publish Date
1995
Start Page
1913

A β-cyclodextrin based fiber-optic chemical sensor: a fractal analysis

A fractal analysis is presented for the binding of pyrene in solution to β-cyclodextrin attached to a fiber-optic chemical sensor. The specific (kl) and non-specific binding rate coefficients and the fractal dimension (Df) (specific binding case only) both tend to increase as the pyrene concentration in solution increases from 12.4 to 124 ng ml-1. Predictive relations for the binding rate coefficient (specific as well as non-specific binding) and for Df (specific binding case only) as a function of pyrene concentration are provided. These relations fit the calculated kl and Df values in the pyrene concentration range reasonably well. Fractal analysis data seem to indicate that an increase in the pyrene concentration in solution increases the "ruggedness" or inhomogeneity on the fiber-optic biosensor surface. The fractal analysis provides novel physical insights into the reactions occuring on the fiber-optic chemical surface and should assist in the design of fiber-optic chemical sensors. © 1995.

Authors
Sadana, A; Alarie, JP; Vo-Dinh, T
MLA Citation
Sadana, A, Alarie, JP, and Vo-Dinh, T. "A β-cyclodextrin based fiber-optic chemical sensor: a fractal analysis." Talanta 42.10 (1995): 1567-1574.
Source
scival
Published In
Talanta
Volume
42
Issue
10
Publish Date
1995
Start Page
1567
End Page
1574

SERS chemical sensors and biosensors: new tools for environmental and biological analysis

This paper describes recent advances in chemical sensors and biosensors based on surface-enhanced Raman scattering (SERS) detection. The SERS-active probes involve silver-coated microstructured substrates designed to amplify the Raman signals of adsorbed molecules and to detect trace chemicals in liquid as well as vapor samples. The development and application of several SERS devices such as a fiber-optic remote sensor and a vapor dosimeter are described. The results illustrate the different uses of the SERS method for the identification and quantification of important environmental and biological compounds. © 1995.

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "SERS chemical sensors and biosensors: new tools for environmental and biological analysis." Sensors and Actuators: B. Chemical 29.1-3 (1995): 183-189.
Source
scival
Published In
Sensors and Actuators B: Chemical
Volume
29
Issue
1-3
Publish Date
1995
Start Page
183
End Page
189

Evaluation of data treatment techniques for improved analysis of fingerprint images

We evaluated four different methods for data treatment of fingerprint images. The first two methods (Lee's method, and Iterative Automated Noise Filtering method) are used to remove signal-independent additive noise from digital images of fingerprints. The two other methods (low-pass and high- pass wavelet filtering), based on the wavelet transform, are employed not only to reduce the noise, but also to enhance the information of the fingerprints, especially details at the ridges. To evaluate these four filtering techniques we analyzed images of various fingerprints provided by the Police Department of Knoxville, Tennessee, and recorded digitally in the laboratory using inexpensive apparatus. Experimental results show that the methods are effective in diverse cases and have potential in forensic analysis of fingerprints.

Authors
Vigo, GP; Hueber, DM; Vo-Dinh, T
MLA Citation
Vigo, GP, Hueber, DM, and Vo-Dinh, T. "Evaluation of data treatment techniques for improved analysis of fingerprint images." Journal of Forensic Sciences 40.5 (1995): 826-837.
Source
scival
Published In
Journal of Forensic Sciences
Volume
40
Issue
5
Publish Date
1995
Start Page
826
End Page
837

Analysis of polynuclear aromatic compounds using laser-excited synchronous fluorescence

Monitoring the presence and distribution of polynuclear aromatic compounds (PACs) in the environment is an important task due to the presence of these species in many types of environmental samples. Molecular fluorescence is often used for this task, usually after extensive sample cleanup and separation, due to the speed and the inherent sensitivity of the technique for PACs. When synchronous fluorescence is used for PAC analysis, the amount of sample pretreatment can often be reduced due to the greater selectivity of the technique relative to conventional fluorescence emission. Another method of increasing sensitivity and selectivity is to use lasers as the excitation source in molecular fluorescence. An added advantage of lasers is the high source coupling and fluorescence collection efficiencies when fiber optics are used for remote sensing applications. In this work, the applicability of laser-excited synchronous fluorescence for the analysis of PAC mixtures is evaluated. A prototype laser-excited synchronous luminescence (LSL) instrument has been previously determined to offer significant advantages over conventional laser-excited fluorescence [C.L. Stevenson and T. Vo-Dinh, Appl. Spectrosc., 47 (1993) 430]. An improved version of the LSL instrument is presented here with superior scanning precision and extended wavelength scanning range. In addition to demonstrating the capabilities of the improved LSL instrument for mixture analysis, the sensitivity of this improved instrument is compared to that of a commercial fluorimeter. Finally, the capability of the LSL instrument to further improve selectivity using time-resolved synchronous fluorescence is illustrated. © 1995.

Authors
Stevenson, CL; Vo-Dinh, T
MLA Citation
Stevenson, CL, and Vo-Dinh, T. "Analysis of polynuclear aromatic compounds using laser-excited synchronous fluorescence." Analytica Chimica Acta 303.2-3 (1995): 247-253.
Source
scival
Published In
Analytica Chimica Acta
Volume
303
Issue
2-3
Publish Date
1995
Start Page
247
End Page
253

In vivo cancer diagnosis of the esophagus using differential normalized fluorescence (DNF) indices.

BACKGROUND AND OBJECTIVE: We report the use of new diagnostic parameters based on the differential normalized fluorescence (DNF) signals for malignant tumor diagnosis. STUDY DESIGN/MATERIALS AND METHODS: Over 200 measurements of endogenous fluorescence from normal and malignant esophageal tissues were performed during routine endoscopy in 48 patients. A pulsed nitrogen-pumped dye laser was used to provide in situ excitation at 410 nm. Direct collection of the fluorescence signal emitted by the tissue was achieved using an intensified photodiode array detector equipped with a fiberoptic probe. RESULTS: The fluorescence signals were normalized with respect to the total fluorescence signal area. The cancer diagnosis indices were defined by the difference between the normalized fluorescence signal of a tumor and the mean value of a reference set of normal tissues. The results of the DNF approach were compared with endoscopic examinations and histopathology interpretations of the biopsy samples. Excellent correlation in the classification of normal and malignant tumors for the samples was found. CONCLUSION: The data indicated that the DNF approach has a significant potential to provide a direct, real-time, and in-situ technique for cancer diagnosis of the esophagus without requiring biopsy of the tumors and time-consuming histopathology tests.

Authors
Vo-Dinh, T; Panjehpour, M; Overholt, BF; Farris, C; Buckley, FP; Sneed, R
MLA Citation
Vo-Dinh, T, Panjehpour, M, Overholt, BF, Farris, C, Buckley, FP, and Sneed, R. "In vivo cancer diagnosis of the esophagus using differential normalized fluorescence (DNF) indices." Lasers Surg Med 16.1 (1995): 41-47.
PMID
7715401
Source
pubmed
Published In
Lasers in Surgery and Medicine
Volume
16
Issue
1
Publish Date
1995
Start Page
41
End Page
47

Mixture analysis using a compact SERS spectrometer

This paper describes the use of a simple, compact, portable spectrometer designed for field measurement using surface-enhanced Raman scattering (SERS) analysis. The instrument yields excellent sensitivity for a wide variety of chemical species, with detection limits in the ppm-ppb range. The SERS analysis of binary and ternary mixtures illustrates the usefulness of the instrument. © 1997 Elsevier Science Ltd. All rights reserved.

Authors
Sutherland, WS; Alarie, JP; Edwards, A; Tran, KC; Hurwitz, M; Selph, W; Margalith, E; Vo-Dinh, T
MLA Citation
Sutherland, WS, Alarie, JP, Edwards, A, Tran, KC, Hurwitz, M, Selph, W, Margalith, E, and Vo-Dinh, T. "Mixture analysis using a compact SERS spectrometer." Analusis 23.1 (1995): 45-48.
Source
scival
Published In
Analusis
Volume
23
Issue
1
Publish Date
1995
Start Page
45
End Page
48
DOI
10.1016/0365-4877(96)84424-X

Surface-enhanced Raman gene probes.

We report for the first time a new type of DNA gene probe based on surface-enhanced Raman scattering (SERS) label detection. The surface-enhanced Raman gene (SERG) probes do not require the use of radioactive labels and have great potential to provide both sensitivity and selectivity. The SERG probe can be used to detect DNA biotargets (e.g., gene sequences, bacteria, viral DNA fragments) via hybridization to DNA sequences complementary to that probe. The analytical figures of merit and its applications in environmental and biomedical areas are discussed.

Authors
Vo-Dinh, T; Houck, K; Stokes, DL
MLA Citation
Vo-Dinh, T, Houck, K, and Stokes, DL. "Surface-enhanced Raman gene probes." Anal Chem 66.20 (October 15, 1994): 3379-3383.
PMID
7978314
Source
pubmed
Published In
Analytical Chemistry
Volume
66
Issue
20
Publish Date
1994
Start Page
3379
End Page
3383

Synchronous luminescence: a new detection technique for multiple fluorescent probes used for DNA sequencing.

A method fo nonradioactive DNA sequencing, which has been marketed commercially, uses four different fluorescent tags to label DNA fragments and fixed-wavelength excitation/fluorescence detection of the labels. This study presents an alternative method of detection based on synchronous luminescence (SL), in which both excitation and emission wavelengths are scanned simultaneously. This approach has proven in the past to have significant advantages over fixed-wavelength luminescence in the analysis and identification of fluorescent analytes. In this paper, the utility of synchronous excitation was investigated as a method for DNA sequencing with fluorescent tags. A laser-based SL instrument, recently developed in this laboratory, was used to resolve the spectra of a mixture of the dyes used in the fluorescence-based sequencing scheme. A preliminary limit of detection of 720 zeptomoles (10(-21) M) of fluorescein isothiocyanate dye in solution was achieved with this instrument. The results presented here suggest that the SL technique could result in an increase in sensitivity and a decrease in error rate of identification during DNA sequencing.

Authors
Stevenson, CL; Johnson, RW; Vo-Dinh, T
MLA Citation
Stevenson, CL, Johnson, RW, and Vo-Dinh, T. "Synchronous luminescence: a new detection technique for multiple fluorescent probes used for DNA sequencing." Biotechniques 16.6 (June 1994): 1104-1111.
PMID
8074876
Source
pubmed
Published In
BioTechniques
Volume
16
Issue
6
Publish Date
1994
Start Page
1104
End Page
1111

SERODS: principle of a new optical data storage system

This paper describes the basic principle of a new approach for large-memory optical disk storage based on the surface-enhanced Raman optical data storage (SERODS) technology. With the SERODS technology, the molecular interactions between the optical layer molecules and the substrate are modified by the writing laser, changing their surface-enhanced Raman scattering (SERS) emitting properties, so that they are encoded to store information as bits. Since the SERS-emitting properties are extremely sensitive to molecular microenvironments (enhancement up to a million fold), lower laser energies (shorter pulses and/or faster rate) and much smaller “molecular holes” are required for the writing process. A reading laser with much lower energy than the writing laser, and a photometric detector tuned to the frequency of the Raman emissions, are used to retrieve the stored information. The SERODS technology has great potential to offer several advantages including high storage density, unique spectral features of the encoded signals, three-dimensional storage capability

Authors
Vo Dinh, T
MLA Citation
Vo Dinh, T. "SERODS: principle of a new optical data storage system." Proc. SPIE - Int. Soc. Opt. Eng. (USA) 2338 (1994): 148-155. (Academic Article)
Source
manual
Published In
Proc. SPIE - Int. Soc. Opt. Eng. (USA)
Volume
2338
Publish Date
1994
Start Page
148
End Page
155

Surface-enhanced Raman optical data storage: a new optical memory with three-dimensional data storage

A new approach for optical data storage based on the surface-enhanced Raman scattering effect was described. The application of this surface-enhanced Raman optical data storage technology for high-density optical data writing and reading in combination with three-dimensional data storage was also shown. This unique feature led to enhanced data transfer rate by allowing multiple tracks or multiple layers to be scanned simultaneously. This unique multiple-reading capacity on three-dimensional level has not yet been seen with any other optical storage technologies currently available.

Authors
Vo-Dinh, T; Stokes, DL
MLA Citation
Vo-Dinh, T, and Stokes, DL. "Surface-enhanced Raman optical data storage: a new optical memory with three-dimensional data storage." Review of Scientific Instruments 65.12 (1994): 3766-3770.
Source
scival
Published In
Review of Scientific Instruments
Volume
65
Issue
12
Publish Date
1994
Start Page
3766
End Page
3770
DOI
10.1063/1.1144504

Biosensors and antibody probes for environmental and biomedical applications

This paper presents an overview of the applications of antibody-based fiber optic sensors. Special focus is devoted to antibody-based fiber optic fluoroimmunosensors developed in our laboratories to detect important pollutants and biochemicals. The fiber optic sensor utilizes antibodies covalently bound or encapsulated on the probe tip. The usefulness of fluoroimmunosensors for environmental and biomedical monitoring is discussed

Authors
Vo Dinh, T
MLA Citation
Vo Dinh, T. "Biosensors and antibody probes for environmental and biomedical applications." Proc. SPIE - Int. Soc. Opt. Eng. (USA) 2293 (1994): 132-138. (Academic Article)
Source
manual
Published In
Proc. SPIE - Int. Soc. Opt. Eng. (USA)
Volume
2293
Publish Date
1994
Start Page
132
End Page
138

Photoactivated luminescence method for rapid screening of polychlorinated biphenyls

This paper describes a new method based on enhanced photoactivated luminescence (EPL) for rapid detection of polychlorinated biphenyls (PCBs). The EPL method described here is a unique procedure combining several processes including (i) photoactivation by UV irradiation, (ii) excitation of the photoproduct complex, and (iii) fluorescence detection of the product. The EPL procedure is simple and rapid and can be performed as a spot test method under field conditions. The methodology for determination of total chlorine content of complex PCB mixtures is described. Limits of detection of PCBs are in the parts-per-billion range. © 1994 American Chemical Society.

Authors
Vo-Dinh, T; Pal, A; Pal, T
MLA Citation
Vo-Dinh, T, Pal, A, and Pal, T. "Photoactivated luminescence method for rapid screening of polychlorinated biphenyls." Analytical Chemistry 66.8 (1994): 1264-1268.
Source
scival
Published In
Analytical Chemistry
Volume
66
Issue
8
Publish Date
1994
Start Page
1264
End Page
1268

Portable surface-enhanced raman spectrometer

We describe the development of a simple and compact spectrometer for use in Raman and Surface-enhanced Raman Scattering (SERS) analysis. The instrument using an avalanche photodiode is designed to use under field conditions with simple optical samples. Examples of measurement of a variety of chemicals are used to illustrate the performance of the instrument.

Authors
Sutherland, WS; Alarie, JP; Stokes, DL; Vo-Dinh, T
MLA Citation
Sutherland, WS, Alarie, JP, Stokes, DL, and Vo-Dinh, T. "Portable surface-enhanced raman spectrometer." Instrumentation Science and Technology 22.3 (1994): 231-239.
Source
scival
Published In
Instrumentation Science and Technology
Volume
22
Issue
3
Publish Date
1994
Start Page
231
End Page
239

Winefordner and molecular spectroscopy-The man and his legacy

Authors
Vo-Dinh, T
MLA Citation
Vo-Dinh, T. "Winefordner and molecular spectroscopy-The man and his legacy." Spectrochimica Acta Part B: Atomic Spectroscopy 49.12-14 (1994): 1225-1227.
Source
scival
Published In
Spectrochimica Acta Part B: Atomic Spectroscopy
Volume
49
Issue
12-14
Publish Date
1994
Start Page
1225
End Page
1227

Gel-based Indo-1 probe for monitoring calcium(ii) ions

This work describes the development of a new gel-based Indo-1 (GBI) fluorescent probe for use in detection of Ca2+. The carbodiimide-binding procedure, which allows the formation of an amide bond between the aromatic carboxylic group of Indo-1 and an amino group of the gel has been selected for this study. In this work, agarose gel, which has an amino terminal group with a six-atom hydrophilic spacer arm, has been chosen for hosting Indo-1. A phase-transfer catalyst was used to allow efficient diffusion of metal ions into the GBI probe. The results indicate that the GBI probe is an efficient and practical system that has the required sensitivity to detect Ca2+ ions in biological fluids for routine monitoring.

Authors
Vo-Dinh, T; Viallet, P; Ramirez, L; Pal, A
MLA Citation
Vo-Dinh, T, Viallet, P, Ramirez, L, and Pal, A. "Gel-based Indo-1 probe for monitoring calcium(ii) ions." Analytical Chemistry 66.6 (1994): 813-817.
Source
scival
Published In
Analytical Chemistry
Volume
66
Issue
6
Publish Date
1994
Start Page
813
End Page
817

Detection of cadmium ion using the fluorescence probe Indo-1

Fluorescence probes for biosensors used for the determination of intracellular concentration of metal ions have been synthesized in order to bind selectivity with a specific cation. Since certain ions exhibit similar chemical properties, binding selectivity with the probes is difficult. In this paper we describe for the first time the interaction between Indo-1, a fluorescence probe representative of a family of "specific chelating compounds" (mainly used for calcium) with the cadmium ion. The fluorescence properties of the cadmium complex are described and a method is proposed to determine the concentrations of both calcium and cadmium ions in aqueous solutions. © 1994.

Authors
Vo-Dinh, T; Viallet, P; Ramirez, L; Pal, A; Vigo, J
MLA Citation
Vo-Dinh, T, Viallet, P, Ramirez, L, Pal, A, and Vigo, J. "Detection of cadmium ion using the fluorescence probe Indo-1." Analytica Chimica Acta 295.1-2 (1994): 67-72.
Source
scival
Published In
Analytica Chimica Acta
Volume
295
Issue
1-2
Publish Date
1994
Start Page
67
End Page
72

Oriented Si and Ge nanocrystals formed in Al2O3 by ion implantation and annealing

Ion implantation followed by thermal annealing in a reducing atmosphere has been used to create a high density of oriented Si and Ge nanocrystals in (0001) Al2O3. Both types of nanocrystals are three-dimensionally aligned with respect to the Al2O3 matrix, but the orientational relationships are different, and the two types of nanocrystals have different shapes in Al2O3. Implantation of Si and Ge in fused silica also produces nanocrystals, but in this case, the nanocrystals are randomly oriented relative to each other.

Authors
White, CW; Budai, JD; Withrow, SP; Pennycook, SJ; Hembree, DM; Zhou, DS; Vo-Dinh, T; Magruder, RH
MLA Citation
White, CW, Budai, JD, Withrow, SP, Pennycook, SJ, Hembree, DM, Zhou, DS, Vo-Dinh, T, and Magruder, RH. "Oriented Si and Ge nanocrystals formed in Al2O3 by ion implantation and annealing." Materials Research Society Symposium Proceedings 316 (1994): 487-491.
Source
scival
Published In
Materials Research Society Symposium Proceedings
Volume
316
Publish Date
1994
Start Page
487
End Page
491

Measurement of DNA adducts using surface-enhanced Raman spectroscopy.

Hazardous pollutants emitted from energy-related technologies, chemical industries, or waste materials are of increasing public concern because of their potential adverse health effects. Many pollutants have chemical groups of toxicological importance that can be characterized and detected by Raman spectroscopy. Raman spectroscopy, however, has not been widely used in trace organic detection, even though the information contained in a Raman spectrum is valuable for chemical identification. One limitation of conventional Raman spectroscopy is its low sensitivity, which often necessitates the use of powerful and costly laser sources for sample excitation. Raman spectroscopists have recently been able to analyze dilute biological samples as a result of enhancements in the Raman scattering cross section by factors up to 10(10) when a compound is adsorbed on or near a special electron-conducting surface. These spectacular enhancement factors of the normally weak Raman scattering process help overcome the low sensitivity of Raman spectroscopy through a combination of electromagnetic and chemical interactions between the analyte molecule and the surface. The technique associated with this phenomenon is known as surface-enhanced Raman scattering spectroscopy (SERS). The special conductive surface responsible for the scattering enhancement is referred to as a SERS substrate. For the past few years we have developed the SERS technique, using practical SERS-active substrate materials based on silver-coated microspheres deposited on glass. A wide variety of biomarkers have been investigated, including benzo[a]pyrene, dibenz[a,h]anthracene epoxides, 1,N9-ethenoadenine, 3,N4-ethenocytosine, and other substances. These biomarkers were measured at nanogram and subnanogram levels. The experimental results are of great analytical interest, since these chemicals are difficult to detect by other techniques, such as luminescence spectroscopy, because of the weak luminescence quantum yields of these DNA adducts. In this paper the potential usefulness of the SERS technique for assessing environmental and health effects from human exposure to toxic pollutants is demonstrated.

Authors
Helmenstine, A; Uziel, M; Vo-Dinh, T
MLA Citation
Helmenstine, A, Uziel, M, and Vo-Dinh, T. "Measurement of DNA adducts using surface-enhanced Raman spectroscopy." J Toxicol Environ Health 40.2-3 (October 1993): 195-202.
PMID
8230295
Source
pubmed
Published In
Journal of Toxicology and Environmental Health
Volume
40
Issue
2-3
Publish Date
1993
Start Page
195
End Page
202
DOI
10.1080/15287399309531787

Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter.

Polycyclic aromatic hydrocarbons (PAHs) are important components of the interstellar medium and carbonaceous chondrites, but have never been identified in the reducing atmospheres of the outer solar system. Incompletely characterized complex organic solids (tholins) produced by irradiating simulated Titan atmospheres reproduce well the observed UV/visible/IR optical constants of the Titan stratospheric haze. Titan tholin and a tholin generated in a crude simulation of the atmosphere of Jupiter are examined by two-step laser desorption/multiphoton ionization mass spectrometry. A range of two- to four-ring PAHs, some with one to four alkylation sites are identified, with net abundance approximately 10(-4) g g-1 (grams per gram) of tholins produced. Synchronous fluorescence techniques confirm this detection. Titan tholins have proportionately more one- and two-ring PAHs than do Jupiter tholins, which in turn have more four-ring and larger PAHs. The four-ringed PAH chrysene, prominent in some discussions of interstellar grains, is found in Jupiter tholins. Solid state 13C NMR spectroscopy suggests approximately equal to 25% of the total C in both tholins is tied up in aromatic and/or aliphatic alkenes. IR spectra indicate an upper limit in both tholins of approximately equal to 6% by mass in benzenes, heterocyclics, and PAHs with more than four rings. Condensed PAHs may contribute at most approximately 10% to the observed detached limb haze layers on Titan. As with interstellar PAHs, the synthesis route of planetary PAHs is likely to be via acetylene addition reactions.

Authors
Sagan, C; Khare, BN; Thompson, WR; McDonald, GD; Wing, MR; Bada, JL; Vo-Dinh, T; Arakawa, ET
MLA Citation
Sagan, C, Khare, BN, Thompson, WR, McDonald, GD, Wing, MR, Bada, JL, Vo-Dinh, T, and Arakawa, ET. "Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter." Astrophys J 414.1 (September 1, 1993): 399-405.
PMID
11539501
Source
pubmed
Published In
The Astrophysical Journal
Volume
414
Issue
1
Publish Date
1993
Start Page
399
End Page
405

Laser-based fiberoptic immunosensors

This paper provides a brief overview of the development and application of fiber-optic antibody-based fluoroimmunosensors (FIS) for measuring environmental pollutants and related biomarkers of human exposure and health effects. The FIS combines the excellent specificity of the antigen/antibody reaction, the high sensitivity of laser excitation, and the versatility of fiber-optics technology. Various types of FIS devices were also used to detect toxic chemicals (such as benzo-a-pyrene) and related DNA adducts (e.g., benzo(a)pyrene tetrol).

Authors
Vo-Dinh, T; Alarie, JP; Sepaniak, MJ
MLA Citation
Vo-Dinh, T, Alarie, JP, and Sepaniak, MJ. "Laser-based fiberoptic immunosensors." Proceedings of SPIE - The International Society for Optical Engineering 1716 (1993): 37-43.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
1716
Publish Date
1993
Start Page
37
End Page
43

Rapid field-screening method for PCBs

The analysis of polychlorinated biphenyls (PCBs) generally requires selectivity and sensitivity. Even after cleanup, PCBs are usually at ultratrace levels in field samples, mixed in with other halocarbons, hydrocarbons, lipids, etc. The levels of PCBs typically found in water, soil, tissue, food, biota, and other matrices of interest are in the parts per billion (ppb) range. Most current measurement techniques for PCBs require chromatographic separations and are not practical for routine analysis. There is a strong need to have rapid and simple techniques to screen for PCBs under field conditions. The use of field screening analysis allows rapid decisions in remedial actions and reduces the need for sample preparations and time-consuming laboratory analyses. Field screening techniques also reduce the cost of clean-up operations. This paper describes a simple screening technique based on room temperature phosphorescence (RTP) and provides an overview of both this analytical procedure to detect trace levels of PCBs in environmental samples.

Authors
Vo-Dinh, T; Watts, W; Miller, GH; Pal, A; Eastwood, D; Lidberg, RL
MLA Citation
Vo-Dinh, T, Watts, W, Miller, GH, Pal, A, Eastwood, D, and Lidberg, RL. "Rapid field-screening method for PCBs." Proceedings of SPIE - The International Society for Optical Engineering 1716 (1993): 490-497.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
1716
Publish Date
1993
Start Page
490
End Page
497

Chemical monitors based on surface-enhanced raman scattering

This paper presents an overview of the development of chemical monitors using the surface- enhanced raman scattering (SERS) technique. The SERS effect is based on recent experimental observations, which have indicated enhancement of the Raman scattering efficiency by factors up to 108 when a compound is adsorbed on rough metallic surfaces having submicron protrusions. The focus of our research efforts is on the development of SERS-active sensors and instrumentation capable of field analysis and remote sensing.

Authors
Vo-Dinh, T; Alarie, JP; Sutherland, WS; Stokes, DL; Miller, GH
MLA Citation
Vo-Dinh, T, Alarie, JP, Sutherland, WS, Stokes, DL, and Miller, GH. "Chemical monitors based on surface-enhanced raman scattering." Proceedings of SPIE - The International Society for Optical Engineering 1716 (1993): 517-524.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
1716
Publish Date
1993
Start Page
517
End Page
524

Surface-enhanced raman vapor dosimeter

Authors
Vo Dinh, T; Stokes, DL
MLA Citation
Vo Dinh, T, and Stokes, DL. "Surface-enhanced raman vapor dosimeter." Applied Spectroscopy 47.10 (1993): 1728-. (Academic Article)
Source
manual
Published In
Applied Spectroscopy
Volume
47
Issue
10
Publish Date
1993
Start Page
1728

Development of a battery-operated portable synchronous luminescence spectrofluorometer

A battery-operated portable synchronous luminescence spectrofluorometer was developed for on-site analysis of groundwater or hazardous waste sites. The instrument is capable of either emission, excitation, or synchronous fluorescence measurements. The instrument is suited for trace analysis of important pollutants such as polyaromatic hydrocarbons, creosotes, and polychlorinated biphenyls in complex mixtures. The ability to perform synchronous luminescence measurements on these samples can reduce the complexity of fluorescence spectra and help in rapid field site characterization. A description of the instrumental components is given and an evaluation of the instrument using anthracene and several oil samples is provided to illustrate the usefulness of the instrument.

Authors
Alarie, JP; Vo-Dinh, T; Miller, G; Ericson, MN; Maddox, SR; Watts, W; Eastwood, D; Lidberg, R; Dominguez, M
MLA Citation
Alarie, JP, Vo-Dinh, T, Miller, G, Ericson, MN, Maddox, SR, Watts, W, Eastwood, D, Lidberg, R, and Dominguez, M. "Development of a battery-operated portable synchronous luminescence spectrofluorometer." Review of Scientific Instruments 64.9 (1993): 2541-2546.
Source
scival
Published In
Review of Scientific Instruments
Volume
64
Issue
9
Publish Date
1993
Start Page
2541
End Page
2546
DOI
10.1063/1.1143916

Laser-excited synchronous luminescence spectroscopy

Authors
Stevenson, CL; Vo-Dinh, T
MLA Citation
Stevenson, CL, and Vo-Dinh, T. "Laser-excited synchronous luminescence spectroscopy." Applied Spectroscopy 47.4 (1993): 430-. (Academic Article)
Source
manual
Published In
Applied Spectroscopy
Volume
47
Issue
4
Publish Date
1993
Start Page
430

Permeation measurements of chemical agents simulants through protective clothing materials

Effective procedures associated with storage and disposal of chemical warfare (CW) agents are important for the protection of civilian populations from inadvertent release of these agents. Emergency groups as well as citizens in surrounding communities need to know the relative effectiveness of various chemical protective clothing (CPC) ensembles in the unlikely event of such releases. A method has been developed for studying permeation of chemical warfare agent simulants through CPC materials. The experimental results characterize some commercially available CPC materials. Thirteen different CPC materials having widely differing compositions were chosen to study the permeation of four different liquid CW simulants (dimethyl methyl phosphonate, diisopropyl methyl phosphonate, malathion, and dibutyl sulfide) through these CPC materials at 25°C. This permeation study involved a newly developed analytical technique employing room temperature fluorescence quenching of an indicator compound, phenanthrene, on filter paper. Various experimental factors such as breakthrough time, rate of permeation and uptake were investigated. On the basis of breakthrough time, the 13 CPC materials could be divided into three groups: most resistant, moderately resistant, and least resistant. Materials in the most resistant category exhibited no permeation by any of the simulants for at least 24 hours. Breakthrough occurred in the least resistant materials in generally less than an hour, and sometimes as soon as a few minutes.

Authors
Pal, T; Griffin, GD; Miller, GH; Watson, AP; Daugherty, ML; Vo-Dinh, T
MLA Citation
Pal, T, Griffin, GD, Miller, GH, Watson, AP, Daugherty, ML, and Vo-Dinh, T. "Permeation measurements of chemical agents simulants through protective clothing materials." Journal of Hazardous Materials 33.1 (1993): 123-141.
Source
scival
Published In
Journal of Hazardous Materials
Volume
33
Issue
1
Publish Date
1993
Start Page
123
End Page
141
DOI
10.1016/0304-3894(93)85067-O

Immunosensors: Principles and Applications

This paper presents an overview of the principles and applications of immunofluorescence spectroscopy in the development of antibody-based fiber-optic sensors. Special focus is devoted to antibody-based fiber-optic fluoroimmunosensors developed in our laboratories to detect important pollutants and biochemicals. The fiber-optic sensor utilizes antibodies covalently bound or encapsulated on the probe tip. The usefulness of fluoroimmunosensors for environmental and biomedical monitoring is discussed. © 1993 Academic Press. All rights reserved.

Authors
Vo-Dinh, T; Sepaniak, MJ; Griffin, GD; Alarie, JP
MLA Citation
Vo-Dinh, T, Sepaniak, MJ, Griffin, GD, and Alarie, JP. "Immunosensors: Principles and Applications." ImmunoMethods 3.2 (1993): 85-92.
Source
scival
Published In
ImmunoMethods
Volume
3
Issue
2
Publish Date
1993
Start Page
85
End Page
92
DOI
10.1006/immu.1993.1042

Surface-enhanced Raman scattering analysis of etheno adducts of adenine

We report surface-enhanced Raman spectroscopy (SERS) detection and analysis of several etheno adducts formed from the metabolism of vinyl chloride: 1,N6-ethenoadenine, 1,N6-ethenoadenosine, and 1,N6-etheno-2′-deoxyadenosine. Spectra of the etheno adducts are compared with unmodified adenine and 2′-deoxyadenosine. Chemical group assignments are made for the SERS peaks of these adducts and the limit at which SERS can detect the adducts is assessed. These assignments are compared with SERS analyses of nucleotides and nucleosides. © 1993.

Authors
Helmenstine, AM; Li, YS; Vo-Dinh, T
MLA Citation
Helmenstine, AM, Li, YS, and Vo-Dinh, T. "Surface-enhanced Raman scattering analysis of etheno adducts of adenine." Vibrational Spectroscopy 4.3 (1993): 359-364.
Source
scival
Published In
Vibrational Spectroscopy
Volume
4
Issue
3
Publish Date
1993
Start Page
359
End Page
364

Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter

Polycyclic aromatic hydrocarbons (PAHs) are important components of the interstellar medium and carbonaceous chondrites, but have never been identified in the reducing atmospheres of the outer solar system. Incompletely characterized complex organic solids (tholins) produced by irradiating simulated Titan atmospheres reproduce well the observed UV/visible/IR optical constants of the Titan stratospheric haze. Titan tholin and a tholin generated in a crude simulation of the atmosphere of Jupiter are examined by two-step laser desorption/multiphoton ionization mass spectrometry. A range of two- to four-ring PAHs, some with one to four alkylation sites are identified, with net abundance ∼10-4 g g-1 (grams per gram) of tholins produced. Synchronous fluorescence techniques confirm this detection. Titan tholins have proportionately more one- and two-ring PAHs than do Jupiter tholins, which in turn have more four-ring and larger PAHs. The four-ringed PAH chrysene, prominent in some discussions of interstellar grains, is found in Jupiter tholins. Solid state 13C NMR spectroscopy suggests ≃25% of the total C in both tholins is tied up in aromatic and/or aliphatic alkenes. IR spectra indicate an upper limit in both tholins of ≃6% by mass in benzenes, heterocyclics, and PAHs with more than four rings. Condensed PAHs may contribute at most ∼10% to the observed detached limb haze layers on Titan. As with interstellar PAHs, the synthesis route of planetary PAHs is likely to be via acetylene addition reactions.

Authors
Sagan, C; Khare, BN; Thompson, WR; Mcdonald, GD; Wing, MR; Bada, JL; Vo-Dinh, T; Arakawa, ET
MLA Citation
Sagan, C, Khare, BN, Thompson, WR, Mcdonald, GD, Wing, MR, Bada, JL, Vo-Dinh, T, and Arakawa, ET. "Polycyclic aromatic hydrocarbons in the atmospheres of Titan and Jupiter." Astrophysical Journal 414.1 (1993): 399-405.
Source
scival
Published In
The Astrophysical Journal
Volume
414
Issue
1
Publish Date
1993
Start Page
399
End Page
405

Investigation of noncalcium interactions of fura-2 by classical and synchronous fluorescence spectroscopy.

Several authors have reported unexpected intracellular spectra of both indo-1 and fura-2. One of the major methodological problems in the evaluation of calcium concentration using fluorescent probes is that it is assumed that only two forms of the dyes are detectable within the cells. We show in this study of fura-2 properties that this calcium probe is pH-sensitive and able to bind to cellular proteins. The excitation spectra of protonated and protein-bound forms of fura-2 exhibit a maximum in the same region as that associated with the calcium-free form (i.e., near 365 nm). The very small shift in the excitation spectra upon proton or protein binding precludes the use of classical methods to determine the spectral composition of mixtures of several forms of fura-2. We therefore used the synchronous fluorescence technique to detect the protein-bound form of fura-2 selectively, in order to assess the pH dependence of the fura-2/protein interaction. The nonspecific binding of fura-2 to proteins is reinforced at acidic pH and inhibited by calcium. The fact that the same type of interaction was found between fura-2 and poly-L-lysine suggests that it could be mediated by basic amino acids. Because of the strong overlap of the excitation spectrum of the unprotonated free fura-2 with those associated with the protonated and protein-bound forms, a cytoplasmic acidification may lead to an artifactual measurement of low calcium levels.

Authors
Bancel, F; Salmon, JM; Vigo, J; Vo-Dinh, T; Viallet, P
MLA Citation
Bancel, F, Salmon, JM, Vigo, J, Vo-Dinh, T, and Viallet, P. "Investigation of noncalcium interactions of fura-2 by classical and synchronous fluorescence spectroscopy." Anal Biochem 204.2 (August 1, 1992): 231-238.
PMID
1443519
Source
pubmed
Published In
Analytical Biochemistry
Volume
204
Issue
2
Publish Date
1992
Start Page
231
End Page
238

DNA adduct formation by 12 chemicals with populations potentially suitable for molecular epidemiological studies.

DNA adduct formation, route of absorption, metabolism and chemistry of 12 hazardous chemicals are reviewed. Methods for adduct detection are also reviewed and approaches to sensitivity and specificity are identified. The selection of these 12 chemicals from the Environmental Protection Agency list of genotoxic chemicals was based on the availability of information and on the availability of populations potentially suitable for molecular epidemiological study. The 12 chemicals include ethylene oxide, styrene, vinyl chloride, epichlorohydrin, propylene oxide, 4,4'-methylenebis-2-chloroaniline, benzidine, benzidine dyes (Direct Blue 6, Direct Black 38 and Direct Brown 95), acrylonitrile and benzyl chloride. While some of these chemicals (styrene and benzyl chloride, possibly Direct Blue 6) give rise to unique DNA adducts, others do not. Potentially confounding factors include mixed exposures in the work place, as well the formation of common DNA adducts. Additional research needs are identified.

Authors
Uziel, M; Munro, NB; Katz, DS; Vo-Dinh, T; Zeighami, EA; Waters, MD; Griffith, JD
MLA Citation
Uziel, M, Munro, NB, Katz, DS, Vo-Dinh, T, Zeighami, EA, Waters, MD, and Griffith, JD. "DNA adduct formation by 12 chemicals with populations potentially suitable for molecular epidemiological studies." Mutat Res 277.1 (July 1992): 35-90. (Review)
PMID
1376441
Source
pubmed
Published In
Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Volume
277
Issue
1
Publish Date
1992
Start Page
35
End Page
90

Currently available permeability and breakthrough data characterizing chemical warfare agents and their simulants in civilian protective clothing materials

The current analysis characterizes chemical protective clothing (CPC) that would be available to civilian emergency personnel responding to possible nerve or vesicant chemical warfare agent release with off-post consequences. Currently available commercial protective garments found in the public domain were identified through contacts with manufacturers, regulatory bodies, and distributors of protective clothing, as well as civilian emergency response personnel who use CPC. When appropriate data were available, individual protective clothing ensembles were further characterized by chemical resistance data for specific agents or their simulants. The literature analysis revealed a wide range of chemical protective garments that have been incompletely evaluated for use in a chemical agent environment.

Authors
Daugherty, ML; Watson, AP; Vo-Dinh, T
MLA Citation
Daugherty, ML, Watson, AP, and Vo-Dinh, T. "Currently available permeability and breakthrough data characterizing chemical warfare agents and their simulants in civilian protective clothing materials." Journal of Hazardous Materials 30.3 (1992): 243-267.
Source
scival
Published In
Journal of Hazardous Materials
Volume
30
Issue
3
Publish Date
1992
Start Page
243
End Page
267
DOI
10.1016/0304-3894(92)87002-W

Surface-enhanced Raman scattering interaction of p-aminobenzoic acid on a silver-coated alumina substrate

The adsorption behavior of p-aminobenzoic acid (PABA) molecules on a silver-coated alumina surface-enhanced Raman scattering (SERS) substrate was investigated. For spotted PABA and PABA in non-polar solvents, the PABA molecule is adsorbed flat on the surface of the SERS substrate. In this orientation, the benzene ring is π-bonded to the substrate, and the molecule is further anchored to the substrate by the binding of the lone pairs of NH2 and COO- groups onto the metal surface. On the other hand, the adsorption behavior of PABA in a polar solvent is greatly influenced by the hydrogen bonding of the amine group with the polar solvent. In this orientation, the molecule is preferentially adsorbed through the COO- and assumes a nonflat orientation on the metal surface

Authors
Bello, JM; Anantha Narayanan, V; Vo Dinh, T
MLA Citation
Bello, JM, Anantha Narayanan, V, and Vo Dinh, T. "Surface-enhanced Raman scattering interaction of p-aminobenzoic acid on a silver-coated alumina substrate." Spectrochim. Acta A, Mol. Spectrosc. (UK) 48A.4 (1992): 563-567. (Academic Article)
Source
manual
Published In
Spectrochim. Acta A, Mol. Spectrosc. (UK)
Volume
48A
Issue
4
Publish Date
1992
Start Page
563
End Page
567
DOI
10.1016/0584-8539(92)80047-Z

Portable surface-enhanced Raman toxic chemical analyzer development

GAMMA-METRICS and Oak Ridge National Laboratory have developed a prototype portable toxic chemical analyzer (TCA) for environmental screening using surface enhanced Raman scattering technology. The focus is on detection of anthropogenic chemicals such as polycyclic aromatic compounds. In this instrument, a laser illuminates a small sample of analyte on a substrate of silver coated particles. Light scattered from the illuminated spot is analyzed to determine the chemicals in the analyte. The development process involved miniaturizing the instrument from a large laboratory table-top device to a small portable package, then ruggedizing the components and the packaging to withstand field conditions. A reference design for a commercial instrument has been developed. The instrument employs internal direct optics or, optionally, an external, in-situ probe connected by fiber optics to

Authors
Selph, WE; Tran, KC; Hurwitz, M; Alarie, JP; Sutherland, WS; Stokes, DL; Pal, T; Vo-Dinh, T
MLA Citation
Selph, WE, Tran, KC, Hurwitz, M, Alarie, JP, Sutherland, WS, Stokes, DL, Pal, T, and Vo-Dinh, T. "Portable surface-enhanced Raman toxic chemical analyzer development." Proceedings of SPIE - The International Society for Optical Engineering 1637 (1992): 180-188.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
1637
Publish Date
1992
Start Page
180
End Page
188

Optical monitor for microbial metabolism for hazardous waste application

A remote detection system for in-situ monitoring of the bioluminescence produced by a microbial `reporter' strain grown in rotary film bioreactors has been developed. Two systems were developed: one using a low-temperature photomultiplier, and one using an avalanche photodiode. The photodiode system was preferred for its sensitivity and portability. Testing was performed on a recombinant constitutive light producing strain. The results indicate that the optical monitor is sensitive enough for direct microbial detection for hazardous waste application.

Authors
Ryan-Baker, M; Vo-Dinh, T; Griffin, GD; Miller, GH; Alarie, JP; Burlage, RS; Palumbo, AV; White, DC; Herbes, S
MLA Citation
Ryan-Baker, M, Vo-Dinh, T, Griffin, GD, Miller, GH, Alarie, JP, Burlage, RS, Palumbo, AV, White, DC, and Herbes, S. "Optical monitor for microbial metabolism for hazardous waste application." Proceedings of SPIE - The International Society for Optical Engineering 1637 (1992): 196-207.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
1637
Publish Date
1992
Start Page
196
End Page
207

Surface-enhanced Raman scattering interaction of p-aminobenzoic acid on a silver-coated alumina substrate

The adsorption behavior of p-aminobenzoic acid (PABA) molecules on a silver-coated alumina surface-enhanced Raman scattering (SERS) substrate was investigated. For spotted PABA and PABA in non-polar solvents, the PABA molecule is adsorbed flat on the surface of the SERS substrate. In this orientation, the benzene ring is π-bonded to the substrate, and the molecule is further anchored to the substrate by the binding of the lone pairs of NH2 and COO- groups onto the metal surface. On the other hand, the adsorption behavior of PABA in a polar solvent is greatly influenced by the hydrogen bonding of the amine group with the polar solvent. In this orientation, the molecule is preferentially adsorbed through the COO± and assumes a non-flat orientation on the metal surface. © 1992.

Authors
Bello, JM; Narayanan, VA; Vo-Dinh, T
MLA Citation
Bello, JM, Narayanan, VA, and Vo-Dinh, T. "Surface-enhanced Raman scattering interaction of p-aminobenzoic acid on a silver-coated alumina substrate." Spectrochimica Acta Part A: Molecular Spectroscopy 48.4 (1992): 563-567.
Source
scival
Published In
Spectrochimica Acta - Part A: Molecular Spectroscopy
Volume
48
Issue
4
Publish Date
1992
Start Page
563
End Page
567

DNA adduct formation by 12 chemicals with populations potentially suitable for molecular epidemiological studies

DNA adduct formation, route of absorption, metabolism and chemistry of 12 hazardous chemicals are reviewed. Methods for adduct detection are also reviewed and approaches to sensitivity and specificity are identified. The selection of these 12 chemicals from the Environmental Protection Agency list of genotoxic chemicals was based on the availability of information and on the availability of populations potentially suitable for molecular epidemiological study. The 12 chemicals include ethylene oxide, styrene, vinyl chloride, epichlorohydrin, propylene oxide, 4,4′-methylenebis-2-chloroaniline, benzidine, benzidine dyes (Direct Blue 6, Direct Black 38 and Direct Brown 95), acrylonitrile and benzyl chloride. While some of these chemicals (styrene and benzyl chloride, possibly Direct Blue 6) give rise to unique DNA adducts, others do not. Potentially confounding factors include mixed exposures in the work place, as well the formation of common DNA adducts. Additional research needs are identified.

Authors
Uziel, M; Munro, NB; Katz, DS; Vo-Dinh, T; Zeighami, EA; Waters, MD; Griffith, JD
MLA Citation
Uziel, M, Munro, NB, Katz, DS, Vo-Dinh, T, Zeighami, EA, Waters, MD, and Griffith, JD. "DNA adduct formation by 12 chemicals with populations potentially suitable for molecular epidemiological studies." Mutation Research - Reviews in Mutation Research 277.1 (1992): 35-90.
Source
scival
Published In
Mutation Research - Reviews in Mutation Research
Volume
277
Issue
1
Publish Date
1992
Start Page
35
End Page
90

Comparative pharmacokinetics of the photosensitizer tin-etiopurpurin in dogs and rats

Photodynamic therapy is a promising new treatment for local eradication of cancer. Little work has been done to define the pharmacokinetics of photodynamic drugs or the variability in drug disposition that may occur between different species and pathophysiological states of tissues. Pharmacokinetic studies of tin-etiopurpurin (SnET2), a lipophilic photosensitizer, were conducted on six Beagle dogs and six Sprague-Dawley rats. Blood was collected up to 24 h following drug administration for measurement of tin-etiopurpurin concentration. Dogs and rats were euthanatized 24 h post-administration and tissues were collected for drug analyses. The plasma drug concentrations were best described by a 2-compartment model (Ct = Ae(-αt) + Be(-βt)). Median distribution and elimination half-lives were 0.24 and 0.34 h and 10.21 and 5.25 h for dogs and rats, respectively. The apparent volumes of distribution were 4.26 ± 1.75 L/kg for dogs and 1.84 ± 0.36 L/kg for rats. Systemic clearance was 7.56 ± 2.45 ml/kg/min and 6.63 ± 0.91 ml/kg/min for dogs and rats, respectively. Drug was detected in all tissues analyzed 24 h after drug administration. Drug was detected only sporadically in skin and muscle and was generally below the limit of detection of the assay. Where comparison could be made, concentrations of SnET2 were significantly greater in all tissues except jejunum of rats compared to dogs 24 h after drug administration.

Authors
Frazier, DL; Barnhill, MA; Vodinh, T; Legendre, AM; Overholt, BF
MLA Citation
Frazier, DL, Barnhill, MA, Vodinh, T, Legendre, AM, and Overholt, BF. "Comparative pharmacokinetics of the photosensitizer tin-etiopurpurin in dogs and rats." Journal of Veterinary Pharmacology and Therapeutics 15.3 (1992): 275-281.
Source
scival
Published In
Journal of Veterinary Pharmacology and Therapeutics
Volume
15
Issue
3
Publish Date
1992
Start Page
275
End Page
281

Passive dosimeter for monitoring ammonia vapor

A method is presented for ammonia detection in the vapor phase that exploits the reaction between fluorescamine and ammonia on a sodium lauryl sulfate (NaLS)-treated paper substrate. The fluorescence intensity of the aquamarine fluorescence product is used as a measure of the air vapor concentration (AVC) of ammonia. The substrate treatment with NaLS enhances the intensity of the fluorescent product and improves the reproducibility of the determination of ammonia. The paper substrate is mounted on a dosimeter and used to monitor exposure to ammonia vapor. The developed dosimeter is a self-contained, badge-sized device that passively collects ammonia on a precoated filter-paper at a rate determined by molecular diffusion. The dosimeter can detect ammonia AVC at the ppm level after only 1 min of exposure. For an 8-h exposure period the limit of detection is ca. 1 ppb. © 1992.

Authors
Pal, T; Pal, A; Miller, GH; Vo-Dinh, T
MLA Citation
Pal, T, Pal, A, Miller, GH, and Vo-Dinh, T. "Passive dosimeter for monitoring ammonia vapor." Analytica Chimica Acta 263.1-2 (1992): 175-178.
Source
scival
Published In
Analytica Chimica Acta
Volume
263
Issue
1-2
Publish Date
1992
Start Page
175
End Page
178

A fiber-optic cyclodextrin-based sensor.

This paper describes the development of a fiber-optic cyclodextrin-based (FCD) sensor. The device uses laser excitation and fluorescence detection with beta-cyclodextrin as the reagent phase, immobilized at the tip of an optical fiber. The sensitivity of the FCD sensor is 14 times as great as that of a bare optical fiber when measurements are made with the fiber immersed in a buffer after a 10-min incubation period. The selectivity of the sensor is illustrated with pyrene as the model compound and 5,6-benzoquinoline as the interferent. An interference study with a contaminated environmental ground water sample is used to illustrate the usefulness of the FCD device.

Authors
Alarie, JP; Vo-Dinh, T
MLA Citation
Alarie, JP, and Vo-Dinh, T. "A fiber-optic cyclodextrin-based sensor." Talanta 38.5 (May 1991): 529-534.
PMID
18965183
Source
pubmed
Published In
Talanta
Volume
38
Issue
5
Publish Date
1991
Start Page
529
End Page
534

Evaluation of the fiber-optic antibody-based fluoroimmunosensor for DNA adducts in human placenta samples.

This paper presents the application of a fiber-optic antibody-based fluoroimmunosensor (FIS) for measuring DNA adducts of benzo[alpha]pyrene in human placenta samples. The FIS combines the excellent specificity of the antigen-antibody reaction, the high sensitivity of laser excitation, and the versatility of fiber-optic technology. The FIS was used to detect benzo[alpha]pyrene tetrol (BPT) after release from DNA by mild acid hydrolysis. These placenta samples contained one molecule of adduct per 10(7) base pairs. The limit of detection of the FIS for BPT is about 14 amol (14 x 10(-18) mol).

Authors
Vo-Dinh, T; Alarie, JP; Johnson, RW; Sepaniak, MJ; Santella, RM
MLA Citation
Vo-Dinh, T, Alarie, JP, Johnson, RW, Sepaniak, MJ, and Santella, RM. "Evaluation of the fiber-optic antibody-based fluoroimmunosensor for DNA adducts in human placenta samples." Clin Chem 37.4 (April 1991): 532-535.
PMID
2015666
Source
pubmed
Published In
Clinical chemistry
Volume
37
Issue
4
Publish Date
1991
Start Page
532
End Page
535

Fiber optic sensor probe for in-situ surface-enhanced Raman monitoring

In this paper we report on the development of a fiber optic sensor using a new detection method based on the surface-enhanced Raman scattering (SERS) technique. The SERS effect is based on recent experimental observations, which have indicated enhancement of the Raman scattering efficiency by factors up to 108 when a compound is adsorbed on rough metallic surfaces having submicron protrusions. In this report we describe the development of the SERS probes for in situ remote sensing.

Authors
Vo-Dinh, T; Stokes, DL; Li, YS; Miller, GH
MLA Citation
Vo-Dinh, T, Stokes, DL, Li, YS, and Miller, GH. "Fiber optic sensor probe for in-situ surface-enhanced Raman monitoring." Proceedings of SPIE - The International Society for Optical Engineering 1368 (1991): 203-209.
Source
scival
Published In
Proceedings of SPIE - The International Society for Optical Engineering
Volume
1368
Publish Date
1991
Start Page
203
End Page
209

Advanced approaches in luminescence and Raman spectroscopy

An overview is given of advanced analytical techniques and instrumentation, such as surface-enhanced Raman scattering (SERS) and antibody-based fiber- optic sensors, used to detect trace levels of chemical pollutants and related biomarkers in complex environmental samples.

Authors
Vo-Dinh, T<