Prof. Gabor Patonay Profile

Prof. Gabor Patonay

Professor at Georgia State Univ

SPIE Involvement:

Conference Program Committee | Author

Publications (31)

Proceedings Article | 17 March 2023 Presentation

Design, synthesis and characterization of copolymerized silica nanoparticle optical probes (Conference Presentation)

Gabor Patonay, Maged Henary

Proceedings Volume PC12398, PC1239806 (2023) https://doi.org/10.1117/12.2654671

KEYWORDS: Nanoparticles, Silica, Molecules, Sensors, Energy transfer, Particles, Nanostructures, Forensic science, Flow cytometry, Energy efficiency

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Proceedings Article | 10 March 2020 Presentation

Preparations and applications of modulated covalent multidye silica nanoparticles (Conference Presentation)

Gabor Patonay, Eman Alsolmy, Gala Chapman, Walid Abdelwahab

Proceedings Volume 11256, 112560C (2020) https://doi.org/10.1117/12.2553107

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Proceedings Article | 4 March 2019 Presentation

Surface modified fluorescent silica nanoparticles and their applications (Conference Presentation)

Gabor Patonay, Maged Henary, Gala Chapman, Walid Abdelwahab

Proceedings Volume 10893, 1089303 (2019) https://doi.org/10.1117/12.2513443

KEYWORDS: Nanoparticles, Silica, Molecules, Luminescence, Fluorescence spectroscopy, Analog electronics, Polymerization, Sensors, Metals, Ions

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During the recent years fluorescence spectroscopy applications focused on using longer wavelength fluorophores and new classes of vehicles delivering fluorophores such as nanoparticles. Silica nanoparticles synthesis is relatively straight forward using any of the well established methods (Strober, Reverse Emulsion, etc.,). The basis of these methods is the use of TEOS to form the silica nanoparticle. In addition to TEOS a wide range of modified TEOS is available commercially or can be synthesized using published synthetic schemes. Many different moieties, molecules can be used as substitution in the TEOS molecules and subsequently using these substituted analogs during the polymerization process of the silica nanoparticle. Following this process virtually any new property can be introduced in the silica nanoparticle. One of these is fluorescence using a wide range of fluorophores including visible or near-infrared dyes due to the wide availability of modified TEOS reactive analogues and reactive dyes. Silica nanoparticles containing copolymerized molecules can be utilized as fluorescence sensors if the copolymerized dye has sensing moieties, such as –COOH for pH measurements. One drawback of the direct facile synthesis using one or more modified TEOS in the same reaction is that the whole silica nanoparticle will have the property as determined by the modified TEOS. For example in the case of dyes containing functional moieties that can complex metal ions dye molecules will be located on the surface and the inner structure as well. For many biomedical and bioanalytical applications it may be desired the silica nanoparticle to have different surface and inner core properties. This can be achieved by using surface re-growth technique. For example the surface of the silica nanoparticle can be made very hydrophobic or hydrophilic opposite of the inner core; two different dyes can be present in these regions or make the silica nanoparticle surface to contain optically active enantiomers. This presentation compares the use of longer wavelength fluorophores to shorter wavelength counterparts. Surface properties can be modified by utilizing molecules that are themselves fluorescent, such as modifying surface hydrophobicity using hydrophobic surface dyes or non-hydrophobic dyes in the core with adding surface hydrophobicity with non-fluorescent hydrophobic molecules. Several additional surface modification moieties will be discussed along with their applications.

Proceedings Article | 15 March 2018 Presentation

Fluorescent multidye copolymerized silica nanoparticles for bioanalytical applications (Conference Presentation)

Gabor Patonay, Gala Chapman, Maged Henary, Walid Abdelwahab

Proceedings Volume 10508, 105080B (2018) https://doi.org/10.1117/12.2294916

KEYWORDS: Nanoparticles, Silica, Luminescence, Molecules, Energy transfer, Fluorescence spectroscopy, Chemistry, Biology, Biochemistry, Biophysics

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Fluorescence spectroscopy has become a widely accepted method in many applications in chemistry, biology, biochemistry and biophysics just to mention a few areas because of its practicality and sensitivity. Major trend for these applications during the recent years is the use of longer wavelength fluorophores and encapsulation of fluorophores by utilizing nanoparticles. Longer fluorescence wavelengths have several advantages such as lower background interference that is especially important in complex biological samples. While many different types of nanoparticles can be utilized for encapsulation of these dyes, silica nanoparticles have significant advantages in biological system. The synthesis of silica nanoparticles is relatively straightforward and covalent copolymerization of fluorescent dyes during the silica nanoparticle synthesis is a easily controllable process by using modified TEOS reactive analogues that are widely available. Adding layers on silica nanoparticles different chemical or sensor functionality can be added to the silica nanoparticle surface. The fluorescence intensity of a fluorescent silica nanoparticle can significantly be increased by enclosing larger number of dye molecules in silica nanoparticles. Dependent on the size of the silica nanoparticle 20-50 or more dye molecules can be included using this copolymerization process. For high dye concentrations in the silica nanoparticle self quenching can be significant but it can be minimized by synthesizing large Stokes’ shift dyes. Using NIR dyes excellent sensitivity can be achieved but one major disadvantage is that most biological fluorescence instruments are designed for shorter excitation wavelengths frequently matching the optical properties of fluorescein, a widely used fluorophore. One approach to make these new fluorescent silica nanoparticles more compatible with widely used optical wavelength windows is the development of fluorescent silica nanoparticles containing copolymerized dyes that are good candidates for fluorescence energy transfer. For example if the donor is fluorescein the excitation wavelength is compatible with most instruments on the market. Systems that contain two or more dyes can be used to achieve long fluorescence wavelengths. This presentation discusses the facile synthesis and practical applications of silica nanoparticles containing copolymerized multiple fluorophores that are suitable for fluorescence energy transfer. Optimization of these systems requires the evaluation of individual dye concentrations (donors, acceptors and intermediators), concentration ratios to achieve high fluorescence. During these studies copolymerized energy transfer fluorescence silica nanoparticles were evaluated for their stability, fluorescence intensity and utility. The surface properties of fluorescence silica nanoparticles were modified by adding hydrophobic or hydrophilic molecules on the surface to achieve biocompatibility. Biocompatibility was evaluated by hemolytic experiments. Typical applications of these particles are for immunochemistry, flow cytometry, CE, forensic applications, biomolecule characterizations, etc.

Proceedings Article | 24 April 2017 Presentation

Copolymerized and bonded silica nanoparticles as labels and pseudostationary phase in bioanalytical applications (Conference Presentation)

Gabor Patonay, Maged Henary, Walid Abdelwahab, Gala Chapman

Proceedings Volume 10079, 100790M (2017) https://doi.org/10.1117/12.2256542

KEYWORDS: Nanoparticles, Silica, Molecules, Luminescence, Biomedical optics, Near infrared, Spectroscopy, Absorption, Metals, Ions

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Silica nanoparticles have been increasingly used in developing bioanalytical, biomedical and in many other applications. Silica nanoparticles can easily be synthesized and with the advent of wide availability of modified TEOS reactive analogues only the researcher imagination is the limit of preparing silica nanoparticles that contain different molecules that are either copolymerized inside of the silica nanoparticle or chemically attached (bonded) to the silica nanoparticle surface. Relatively non-porous silica nanoparticles can contain copolymerized dyes for the creation of bright fluorescence labels while the surface of these silica nanoparticles can be bonded with reactive moieties that are suitable for covalently labeling the molecule of interest. Also the surface bonded moieties can serve other purposes, e.g., molecular recognition either on a non-fluorescent or fluorescent silica nanoparticle. As far as the fluorescent nanoparticles development concerns near-infrared (NIR) absorbing carbocyanine dyes have been increasingly used as they can be useful for developing bioanalytical, biomedical methods and in many other applications. Carbocyanines are preferred as they are relatively easy to synthesize and can be designed to achieve particular spectroscopic properties. For example either copolymerized or surface bound dyes can contain appropriate functional moieties absorption and fluorescence properties change when it is complexed to metal ions, to detect pH changes, bind to biological molecules, etc. Fluorescence intensity of carbocyanines significantly increases by enclosing several dye molecules in a single silica nanoparticle due to shielding however self quenching may become a problem at high dye concentrations in confined spaces. Large Stokes’ shift dyes can significantly decrease this problem. This can be achieved by substituting meso position halogens in the NIR fluorescent carbocyanines with a linker containing amino moiety which can also serve as linker to covalently attach the dye molecule during the nanoparticle synthesis. This presentation discusses facile synthesis and applications of silica nanoparticles containing copolymerized fluorophores and/or surface bound moieties. Applications include silica nanoparticles containing several dye molecules as bright labels in immunochemical uses, cell imaging and forensic applications for latent blood detection. This latter application was developed using leuco fluorescein copolymerized silica nanoparticles. This synthesis proved that copolymerized dyes can be further modified after the dye containing silica nanoparticle was formed. Surface bound moiety examples will be given for capillary electrochromatography using amino acid-bonded silica nanoparticles as pseudostationary phases as chiral selectors.

Proceedings Article | 22 April 2016 Presentation + Paper

Fluorescent silica nanoparticles containing covalently bound dyes for reporter, marker, and sensor applications

Gabor Patonay, Maged Henary, Gala Chapman, Kyle Emer, Sidney Crow

Proceedings Volume 9723, 97230Q (2016) https://doi.org/10.1117/12.2217869

KEYWORDS: Nanoparticles, Silica, Sensors, Near infrared, Luminescence, Particles, Absorption, Molecules, Bioalcohols, Quantum efficiency

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Proceedings Article | 16 March 2015 Paper

NIR fluorescent silica nanoparticles as reporting labels in bioanalytical applications

Gabor Patonay, Maged Henary, Gala Chapman, Kyle Emer, Sydney Crow

Proceedings Volume 9339, 933904 (2015) https://doi.org/10.1117/12.2085060

KEYWORDS: Nanoparticles, Silica, Near infrared, Luminescence, Molecules, Quantum efficiency, Chromophores, Dysprosium, Absorption, Fluorescence spectroscopy

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The use of the NIR spectral region (650-900 nm) for bioanalytical and biomedical analyses is advantageous due to the inherently lower background interference in biological matrices and the high molar absorptivities of NIR chromophores. There are several different groups of NIR fluorescing dye are available for bioanalytical applications. One of these groups, NIR carbocyanines are increasingly used in analytical, bioanalytical and medical applications. These dyes can be used as reporter labels for sensitive bioanalytical use, such as immunochemistry. Due to the spectroscopic sensitivity of NIR carbocyanines for polarity changes in the microenvironment fluorescence quantum yield can vary significantly dependent on the microenvironment. NIR dyes can have relatively low fluorescent quantum yields as compared to visible fluorophores, especially in aqueous buffers but the lower quantum yield is compensated for by a much higher molar absorptivity. The fluorescence intensity of NIR reporting labels can significantly be increased by enclosing several dye molecules in silica nanoparticles. Incorporation of NIR dyes in silica nanoparticles creates a unique challenge as these dyes can be unstable under certain chemical conditions present during silica nanoparticles syntheses. In addition, self quenching may also become a problem for carbocyanines at higher a concentrations that typically found inside of NIR dye loaded silica nanoparticles. Dyes possessing high Stokes’ shift can significantly reduce this problem. NIR carbocyanines are uniquely positioned for achieving this goal using a synthetic route that substitutes meso position halogens in NIR fluorescent carbocyanines with a linker containing amino moiety, which can also serve as a linker for covalently attaching the dye molecule to the nanoparticle backbone. The resulting silica nanoparticles can contain a large number of NIR dyes dependent on their size. For example some NIR fluorescent silica nanoparticle labels prepared that has an average radius around 15 nm, contains 16-20 covalently attached dye molecules inside of the nanoparticle. The primary applications of these particles are for bright fluorescent labels that can be used in applications such as immunochemistry, flow cytometry, and many other applications.

Proceedings Article | 5 March 2014 Paper

Use of fluorescent NIR dyes in silica nanoparticles and as enzyme substrates in bioanalytical applications

Gabor Patonay, Gala Chapman, Garfield Beckford, Maged Henary, Holly Ellis

Proceedings Volume 8956, 89560U (2014) https://doi.org/10.1117/12.2045795

KEYWORDS: Nanoparticles, Near infrared, Silica, Luminescence, Particles, Molecules, Quantum efficiency, Absorption, Chlorine, Sulfur

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Near-Infrared (NIR) absorbing carbocyanine dyes have been increasingly used in analytical, biological and medical fields as they can be useful for developing bioanalytical and biomedical methods. The utilization of the NIR spectral region (650-900 nm) is advantageous and is due to the inherently lower background interference and the high molar absorptivities of NIR chromophores. NIR dyes typically have relatively lower fluorescent quantum yield as compared to visible fluorophores, but much higher molar absorptivities which more than compensates for the lower quantum yields regarding detection limits. Fluorescence intensity of NIR dyes significantly increases by enclosing several dye molecules in silica nanoparticles. Self quenching may become a problem for carbocyanines at such high concentrations that may be present in the silica nanoparticles. Dyes that have large Stokes’ shift can significantly decrease this problem. Increased Stokes’ shift for carbocyanines dyes can be achieved by substituting meso position halogens with a linker containing aliphatic or aromatic amino moiety which also serves as a covalent linker for attaching the dye molecule to the nanoparticle backbone. The primary applications of these particles are for bright fluorescent labels to be used in bioanalytical applications such as immunochemistry, flow cytometry, etc. This work also discusses the use of NIR dyes as enzyme substrates. NIR dyes can be used as enzyme substrates and hence for characterization of enzyme activity. The well characterized alkenesulfonate monooxygenase enzyme was chosen for these studies. Carbocyanines containing alkylsulfonate moieties do not exhibit significant fluorescence change upon binding to biomolecules however otherwise identical NIR dye analogs that contain alkylaldehyde moiety at the same position do exhibit changes which can be utilized for characterization of alkenesulfonate monooxygenase enzyme activity using near infrared dyes as substrates. In this study a new class of sulfonated penta- and heptamethine dyes were used as substrates in vitro utilizing a photo-reduced riboflavin mononucleotide (FMN) with a glucose/ glucose-oxygenase oxygen scavenging system. Laser Induced Fluorescence (LIF) detected CZE was utilized to detect the sulfonated and de-sulfonated carbocyanines. The lower fluorescence quantum yield of the less water soluble alkylaldehyde analogs was detected and enzyme activity was characterized.

Proceedings Article | 21 February 2013 Paper

NIR fluorescent dyes: versatile vehicles for marker and probe applications

Gabor Patonay, Gala Chapman, Garfield Beckford, Maged Henary

Proceedings Volume 8596, 859604 (2013) https://doi.org/10.1117/12.2011595

KEYWORDS: Near infrared, Nanoparticles, Luminescence, Silica, Molecules, Absorption, Particles, Bioalcohols, Dysprosium, Fluorescent markers

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The use of the NIR spectral region (650-900 nm) is advantageous due to the inherently lower background interference and the high molar absorptivities of NIR chromophores. Near-Infrared (NIR) dyes are increasingly used in the biological and medical field. The binding characteristics of NIR dyes to biomolecules are possibly controlled by several factors, including hydrophobicity, size and charge just to mention a few parameters. Binding characteristics of symmetric carbocyanines and found that the hydrophobic nature of the NIR dye is only partially responsible for the binding strength. Upon binding to biomolecules significant fluorescence enhancement can be observed for symmetrical carbocyanines. This fluorescence amplification facilitates the detection of the NIR dye and enhances its utility as NIR reporter. This manuscript discusses some probe and marker applications of such NIR fluorescent dyes. One application discussed here is the use of NIR dyes as markers. For labeling applications the fluorescence intensity of the NIR fluorescent label can significantly be increased by enclosing several dye molecules in nanoparticles. To decrease self quenching dyes that have relatively large Stokes’ shift needs to be used. This is achieved by substituting meso position halogens with amino moiety. This substitution can also serve as a linker to covalently attach the dye molecule to the nanoparticle backbone. We report here on the preparation of NIR fluorescent silica nanoparticles. Silica nanoparticles that are modified with aminoreactive moieties can be used as bright fluorescent labels in bioanalytical applications. A new bioanalytical technique to detect and monitor the catalytic activity of the sulfur assimilating enzyme using NIR dyes is reported as well. In this spectroscopic bioanalytical assay a family of Fischer based n-butyl sulfonate substituted dyes that exhibit distinct variation in absorbance and fluorescence properties and strong binding to serum albumin as its sulfonic acid moiety is modified to less water soluble moiety was identified. In polar solvents, these water soluble compounds are strongly fluorescent, however form the less soluble aggregated species with virtual loss of fluorescence when the sulfonate groups are cleaved by enzymatic activity to form the corresponding straight chain alkyl aldehyde derivatives. To achieve this conversion in vitro photo-reduced riboflavin mononucleotide (FMN) with a glucose/ glucose-oxygenase oxygen scavenging system was utilized. The reduced FMN serves as a key substrate in the enzymatic desulfonation. Once the FMNH2 was produced the desulfonation reaction was characterized by using Laser Induced Fluorescence Capillary Zone Electropheresis (LIF-CZE). This method can be utilized as an assay to detect the enzyme activity in vitro with the possibilities of in vivo applications.

Proceedings Article | 2 February 2012 Paper

Novel water soluble NIR dyes: does charge matter?

Gabor Patonay, Maged Henary, Garfield Beckford, Alison Daube

Proceedings Volume 8233, 823307 (2012) https://doi.org/10.1117/12.913123

KEYWORDS: Near infrared, Luminescence, In vivo imaging, Absorption, Proteins, Molecules, Dysprosium, Biomedical optics, Semiconductor lasers, Near infrared spectroscopy

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Proceedings Article | 1 March 2010 Paper

Near-infrared fluorophores as biomolecular probes

Gabor Patonay, Garfield Beckford, Lucjan Strekowski, Maged Henary, Yonathan Merid

Proceedings Volume 7576, 757607 (2010) https://doi.org/10.1117/12.849451

KEYWORDS: Near infrared, Luminescence, Proteins, Molecules, Chemistry, Chromophores, Dysprosium, Near infrared spectroscopy, Spectroscopy, Quantum efficiency

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Proceedings Article | 21 February 2009 Paper

Near-infrared dyes for molecular probes and imaging

Gabor Patonay, Garfield Beckford, Lucjan Strekowski, Maged Henary, Jun Seok Kim, Sidney Crow

Proceedings Volume 7190, 71900J (2009) https://doi.org/10.1117/12.813562

KEYWORDS: Near infrared, Luminescence, Molecules, Absorption, Dysprosium, Chlorine, In vivo imaging, Chromophores, Proteins, Quantum efficiency

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Proceedings Article | 13 February 2007 Paper

Near-infrared dyes and upconverting phosphors as biomolecule labels and probes

Gabor Patonay, Lucjan Strekowski, Diem-Ngoc Nguyen, Kim Jun Seok

Proceedings Volume 6449, 644907 (2007) https://doi.org/10.1117/12.703197

KEYWORDS: Near infrared, Chemistry, Luminescence, Silicon, Energy transfer, Absorption, Crystals, Biological research, Forensic science, Particles

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Near-Infrared (NIR) absorbing chromophores have been used in analytical and bioanalytical chemistry extensively, including for determination of properties of biomolecules, DNA sequencing, immunoassays, capillary electrophoresis (CE) separations, etc. The major analytical advantages of these dyes are low background interference and high molar absorptivities. NIR dyes have additional advantages due to their sensitivity to microenvironmental changes. Spectral changes induced by the microenvironment are not desirable if the labels are used as a simple reporting group, e.g., during a biorecognition reaction. For these applications upconverting phosphors seem to be a better choice. There are several difficulties in utilizing upconverting phosphors as reporting labels. These are: large physical size, no reactive groups and insolubility in aqueous systems. This presentation will discuss how these difficulties can be overcome for bioanalytical and forensic applications. During these studies we also have investigated how to reduce physical size of the phosphor by simple grinding without losing activity and how to attach reactive moiety to the phosphor to covalently bind to the biomolecule of interest. It has to be emphasized that the described approach is not suitable for medical applications and the results of this research are not applicable in medical applications. For bioanalytical and forensic applications upconverting phosphors used as reporting labels have several advantages. They are excited with lasers that are red shifted respective to phosphorescence, resulting in no light scatter issues during detection. Also some phosphors are excited using eye safe lasers. In addition energy transfer to NIR dyes is possible, allowing detection schemes using donor-acceptor pairs. Data is presented to illustrate the feasibility of this phenomenon. If microenvironmental sensitivity is required, then specially designed NIR dyes can be used as acceptor labels. Several novel dyes have been synthesized in our laboratories for that purpose.

Proceedings Article | 14 February 2006 Open Access

Near-infrared probes: design and applications

G. Patonay, L. Strekowski, A. Raszkiewicz, J. Kim

Proceedings Volume 6097, 609709 (2006) https://doi.org/10.1117/12.647836

KEYWORDS: Near infrared, Luminescence, Chlorine, Molecules, Chromophores, Absorption, Analytical research, Chemistry, Sodium, Biological research

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Proceedings Article | 23 May 2005 Paper

Near-infrared fluorescent dyes for fiber optic sensing

Gabor Patonay, Jun Seok Kim, Martial Medou-Ovono, Lucjan Strekowski

Proceedings Volume 5855, (2005) https://doi.org/10.1117/12.623993

KEYWORDS: Near infrared, Luminescence, Ions, Metals, Fiber optics sensors, Optical fibers, Molecules, Sensors, Chemical analysis, Fiber optics

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Proceedings Article | 16 December 2004 Paper

Development of new near-infrared and leuco-dye optical systems for forensic and crime fighting applications

Gabor Patonay, Lucjan Strekowski, Jozef Salon, Martial Medou-Ovono, James Krutak, Jeffrey Leggitt, Heather Seubert, Rhonda Craig

Proceedings Volume 5616, (2004) https://doi.org/10.1117/12.567855

KEYWORDS: Near infrared, Luminescence, Blood, Pepper spray, Light sources, Forensic science, Chemistry, Optical filters, Rhodamine, Light emitting diodes

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SPIE Journal Paper | 1 October 2002 Open Access

DNA and protein applications of near-infrared dyes

John Sowell, Lucjan Strekowski, Gabor Patonay

JBO, Vol. 7, Issue 04, (October 2002) https://doi.org/10.1117/12.10.1117/1.1502262

KEYWORDS: Proteins, Luminescence, Capillaries, Laser induced fluorescence, Fluorescence spectroscopy, Near infrared, Molecules, Semiconductor lasers, Visible radiation, Light scattering

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Proceedings Article | 21 June 2002 Open Access

Near-infrared dyes in biotechnology and bioanalysis: overview and future trends

John Sowell, Lucjan Strekowske, Gabor Patonay

Proceedings Volume 4626, (2002) https://doi.org/10.1117/12.472077

KEYWORDS: Near infrared, Fluorescence spectroscopy, Luminescence, Proteins, Capillaries, Biotechnology, Molecules, Visible radiation, Laser induced fluorescence, Chemistry

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Fluorescence detection is one ofthe most popular detection methods used in bioanalytical analysis. Fluorescence detection methods offer the advantages ofhigh sensitivity combined with selectivity. Generally, the chromophore is attached to the species of interest and acts as a reporter molecule. Most fluorescence detection schemes involve the use ofvisible fluorophores, fluorescein being one ofthe most common. A problem often encountered with the used of fluorescence detection in the visible region of the spectrum is sample autofluorescence. Many compounds have intrinsic fluorescence in this region. Background fluorescence is present throughout the visible and UV region ofthe spectmm (fig 1). Consequently, background noise can be very high and, as a result, the overall sensitivity of the measurement is decreased. Very few molecules exhibit intrinsic fluorescence in the near infrared region of the spectrum (650-1 100 nm). As a result, the background noise associated with fluorescence detection in the visible region is nearly eliminated. Consequently, the near infrared region offers the potential for significant improvements in sensitivity, especially in situations where matrix autofluorescence is a concern. Near infrared fluorescence detection methods are therefor well suited to bioanalytical applications. Furthermore, light scatter, another source of interference, is decreased in the near infrared region due to its ii)dependence. Detection at 820 nm offers a six-fold reduction in light scatter over detection at 500 nm. Instrumentation associated with the use of near infrared dyes also offers some advantages over traditional instrumentation. Laser induced fluorescence is one ofthe most commonly used fluorescence detection methods, due to the high intensity associated with laser light. Lasers that operate in the visible region ofthe spectrum are often bulky, expensive, and have limited operational lifetimes. The advent of solid state diode lasers do not have any of the aforementioned disadvantages. They are mgged, inexpensive, compact, and have long operational lifetimes. The typical signal transducer for fluorescence measurements is the photomultiplier tube (PMT). However, PMT's make poor choices for signal transducers in the near infrared region due to their low quantum yields at these wavelengths. Consequently, Avalanche photodiodes (APD) are used. APD's offer high quantum efficiencies in the near infrared region. Additionally, they are rugged, cheap, and have long operational lifetimes.

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Proceedings Article | 7 May 1997 Paper

Analytical applications of near-infrared fluorescent probes

Gabor Patonay, Leila Tarazi, Abraham George, Koen Van Aken, Tadeusz Gorecki, Lucjan Strekowski

Proceedings Volume 2980, (1997) https://doi.org/10.1117/12.273562

KEYWORDS: Ions, Luminescence, Metals, Near infrared, Absorption, Semiconductor lasers, Fiber optics, Chromophores, Quantum efficiency, Absorbance

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Proceedings Article | 12 April 1996 Paper

NIR-PRFS fiber optic corrosion sensor

Robert Chin, William Halliday, Clay Cruce, Noe Salazar, Keith Jamison, Gabor Patonay, Lucjan Strekowski, Tadeusz Gorecki, Mokhtar Maklad

Proceedings Volume 2682, (1996) https://doi.org/10.1117/12.237663

KEYWORDS: Ions, Near infrared, Luminescence, Corrosion, Sensors, Metals, Aluminum, Fiber optics sensors, Fiber optics, Iron

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Proceedings Article | 9 October 1995 Paper

Near-infrared fluorescence sensor technology

Lawrence Evans, Guillermo Casay, Dong Dai, Gabor Patonay

Proceedings Volume 2504, (1995) https://doi.org/10.1117/12.224115

KEYWORDS: Ions, Metals, Luminescence, Semiconductor lasers, Near infrared, Sensors, Optical fibers, Absorption, Absorbance, Fluorescence spectroscopy

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Proceedings Article | 8 May 1995 Paper

New near-infrared dyes for applications in bioanalytical methods

Narasimhachari Narayanan, Garrick Little, Ramesh Raghavachari, Gabor Patonay

Proceedings Volume 2388, (1995) https://doi.org/10.1117/12.208471

KEYWORDS: Near infrared, Luminescence, Dysprosium, Absorbance, Proteins, Chemistry, Infrared radiation, Spectroscopy, Quantum efficiency, Chromophores

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Proceedings Article | 8 May 1995 Paper

Immunoassays for pesticide monitoring

Ingrid Wengatz, Ferenc Szurdoki, Anand Swamy, Lawrence Evans, Gabor Patonay, Eric Stimmann, Michael Delwiche, Donald Stoutamire, Shirley Gee, Bruce Hammock

Proceedings Volume 2388, (1995) https://doi.org/10.1117/12.208500

KEYWORDS: Near infrared, Semiconductor lasers, Sensors, Photodiodes, Luminescence, Molecules, Biopolymers, Absorbance, Fluorescence spectroscopy, Proteins

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Proceedings Article | 21 October 1994 Paper

Detection of toxic metal ions with near-infrared compounds

Guillermo Casay, Tibor Czuppon, Lawrence Evans, Gabor Patonay

Proceedings Volume 2293, (1994) https://doi.org/10.1117/12.190975

KEYWORDS: Ions, Metals, Near infrared, Luminescence, Semiconductor lasers, Molecules, Polymers, Absorbance, Diodes, Fiber optics

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Proceedings Article | 27 July 1994 Paper

Long-wavelength fluorescent probes--chemistry and semiconductor lasers: a difficult marriage

G. Casay, Tibor Czuppon, Gabor Patonay

Proceedings Volume 2138, (1994) https://doi.org/10.1117/12.181362

KEYWORDS: Semiconductor lasers, Near infrared, Luminescence, Metals, Optical fibers, Absorbance, Ions, Diodes, Light sources, Sensors

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Proceedings Article | 27 July 1994 Paper

Near-IR biosensor for evanescent wave immunoassays

Joel Golden, Lisa Shriver-Lake, Narasimhachari Narayanan, Gabor Patonay, Frances Ligler

Proceedings Volume 2138, (1994) https://doi.org/10.1117/12.181363

KEYWORDS: Biosensors, Near infrared, Luminescence, Semiconductor lasers, Proteins, Camera shutters, Fiber optics, Mirrors, Laser development, Sensors

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Proceedings Article | 10 March 1994 Paper

Investigation of a near-infrared fiber optic immunosensor

Maryam Daneshvar, Guillermo Casay, Malgorzata Lipowska, Gabor Patonay, Lucjan Strekowski

Proceedings Volume 2068, (1994) https://doi.org/10.1117/12.170650

KEYWORDS: Near infrared, Luminescence, Fiber optics, Sensors, Optical fibers, Polymethylmethacrylate, Fluorescence spectroscopy, Chemistry, Optical design, Visible radiation

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Proceedings Article | 18 May 1993 Paper

Near-infrared fluorescent probes

Guillermo Casay, Tibor Czuppon, Jacek Lipowski, Gabor Patonay

Proceedings Volume 1885, (1993) https://doi.org/10.1117/12.144722

KEYWORDS: Luminescence, Metals, Ions, Near infrared, Polymers, Optical fibers, Fiber optics, Lithium, Semiconductor lasers, Absorbance

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Proceedings Article | 30 April 1993 Paper

Near-infrared fluorescence in fiber optic applications

Guillermo Casay, Tibor Czuppon, Narasimhachari Narayanan, Gabor Patonay

Proceedings Volume 1796, (1993) https://doi.org/10.1117/12.143498

KEYWORDS: Luminescence, Fiber optics, Metals, Near infrared, Molecules, Ions, Semiconductor lasers, Absorption, Chromophores, Visible radiation

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Proceedings Article | 1 May 1992 Paper

Near-infrared laser diodes in monitoring applications

Gabor Patonay, Jyh-Myng Zen, Tibor Czuppon

Proceedings Volume 1637, (1992) https://doi.org/10.1117/12.59333

KEYWORDS: Near infrared, Semiconductor lasers, Molecules, Absorption, Luminescence, Chromophores, Environmental monitoring, Spectroscopy, Metals, Fluorescence spectroscopy

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Proceedings Article | 1 July 1991 Paper

Semiconductor lasers in analytical chemistry

Gabor Patonay, Miquel Antoine, A. Boyer

Proceedings Volume 1435, (1991) https://doi.org/10.1117/12.44230

KEYWORDS: Semiconductor lasers, Luminescence, Absorption, Near infrared, Spectroscopy, Chemistry, Molecules, Laser spectroscopy, Fluorescence spectroscopy, Chromophores

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Laser spectroscopy has become a widely used popular technique in analytical chemistry during the laser decade. Numerous studies have documented the results of the advantages of lasers (low detection limits, for example); however, most of the applications have focused on the use of relatively expensive lasers. Much less effort has been directed toward the development of analytical methods using semiconductor lasers. With the development of semiconductor lasers a new approach to laser enhanced analytical methods has become possible. Semiconductor lasers are a source of monochromatic, tunable coherent beams of light, characteristic of other types of lasers, with the additional benefit of compactness. At the present time semiconductor lasers are available only for the red and the near-infrared (NIR) region of the spectrum, a situation that required the development of new methods for giving analytically useful signals in the NIR spectral region. The shortwave NIR region of the spectrum is advantageous due to its relatively low interference. Fluorescence spectroscopy is an inherently sensitive technique; however, the analysis of complicated biological samples may require the simultaneous acquisition of absorption spectra. In this regard absorption measurement involves the use of multiple spectroscopic parameters to increase the specificity of the measurement. Laser diodes are excellent light sources for both absorption and fluorescence spectroscopy. Low detection limits may be achieved using the intracavity method for absorption measurements. Moreover, laser intracavity spectroscopy has an important advantage when implemented with laser diodes: the built-in integral monitoring photodiode (PIN) can be used as a detector. The advantages and disadvantages of different methods of laser diode control are discussed in this paper, as are several different analytical applications. Simultaneous fluorescence detection is also possible with an additional detector. Superior detection limits may be achieved using NIR laser diode excited fluorescence spectroscopy. In this paper the use of NIR laser diode spectroscopy in analytical chemistry is demonstrated.

Showing 5 of 31 publications

Proceedings Volume Editor (1)

SPIE Conference Volume | 27 July 1994

Longer Wavelength Lasers and Applications

Conference Committee Involvement (22)

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications XVI

25 January 2025 | San Francisco, California, United States

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications XV

30 January 2024 | San Francisco, California, United States

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications XIV

31 January 2023 | San Francisco, California, United States

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications XIII

6 March 2021 | Online Only, California, United States

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications XII

4 February 2020 | San Francisco, California, United States

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications XI

4 February 2019 | San Francisco, California, United States

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications X

29 January 2018 | San Francisco, California, United States

Reporters, Markers, Dyes, Nanoparticles, and Molecular Probes for Biomedical Applications IX

30 January 2017 | San Francisco, California, United States

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