Dr. Michael S. Wong Profile

Dr. Michael S. Wong

at Rice Univ

SPIE Involvement:

Author

SPIE Journal Paper | 1 November 2007 Open Access

Stability assessment of indocyanine green within dextran-coated mesocapsules by absorbance spectroscopy

Mohammad Yaseen, Jie Yu, Michael Wong, Bahman Anvari

JBO, Vol. 12, Issue 06, 064031, (November 2007) https://doi.org/10.1117/12.10.1117/1.2821423

KEYWORDS: Absorbance, Molecules, Polymers, Indocyanine green, Molecular aggregates, Particles, Absorption spectroscopy, Spectroscopy, Molecular interactions, Tumors

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Proceedings Article | 13 February 2007 Paper

Encapsulation of indocyanine green within nano-assembled capsules changes its optical properties

Mohammad Yaseen, Jie Yu, Michael Wong, Bahman Anvari

Proceedings Volume 6449, 644908 (2007) https://doi.org/10.1117/12.707211

KEYWORDS: Absorbance, Molecules, Indocyanine green, Molecular aggregates, Polymers, Optical properties, Absorption, Particles, Near infrared, Tissue optics

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SPIE Journal Paper | 1 January 2006 Open Access

Synchronous fluorescence spectroscopic characterization of DMBA-TPA-induced squamous cell carcinoma in mice

Parmeswaran Diagaradjane, Mohammad Yaseen, Jie Yu, Michael Wong, Bahman Anvari

JBO, Vol. 11, Issue 01, 014012, (January 2006) https://doi.org/10.1117/12.10.1117/1.2167933

KEYWORDS: Tissues, Tumors, Skin, Luminescence, Statistical analysis, Fluorescence spectroscopy, Spectroscopy, Collagen, Diagnostics, Biological research

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Proceedings Article | 28 April 2005 Paper

Synthesis of high-quality CdSe nanocrystals in heat transfer fluids

Subashini Asokan, Alessandra Carreon, Zuze Mu, Karl Krueger, Ammar Alkhawaldeh, Vicki Colvin, Michael Wong

Proceedings Volume 5705, (2005) https://doi.org/10.1117/12.597272

KEYWORDS: Quantum dots, Particles, Nanocrystals, Nanobiophotonics, Biomedical optics, Semiconductors, Nanoparticles, Optoelectronics, Industrial chemicals, Light emitting diodes

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Proceedings Article | 25 April 2005 Paper

Autofluorescence characterization of DMBA-TPA-induced two-stage carcinogenesis in mouse skin for the early detection of tissue transformation

Parmeswaran Diagaradjane, Mohammed Yaseen, Jie Yu, Michael Wong, Bahman Anvari

Proceedings Volume 5686, (2005) https://doi.org/10.1117/12.589328

KEYWORDS: Tissues, Skin, Luminescence, Tumors, Statistical analysis, Collagen, Diagnostics, Tissue optics, Fluorescence spectroscopy, Cancer

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The use of autofluorescence technique in the characterization of the sequential tissue transformation process in 7,12-dimethylbenz(a)anthracene and 12-O-tetradecanoylphorbol-13-acetate (DMBA & TPA) induced two-stage mouse skin carcinogenesis model in conjunction with a suitable statistical method is being explored. The fluorescence excitation emission matrix (EEM) from experimental group (n=40; DMBA/TPA application), control group (n=6; acetone application) and the blank group (n=6; no application of DMBA/TPA or acetone) were measured every week using Fluoromax3 spectrofluorometer coupled with a waveguide fiber optic bundle (JY Horiba, NJ). The EEM was recorded for 19 excitation wavelengths from 280 to 460 nm at 10 nm intervals and the fluorescence emission was scanned from 300 to 750 nm. During the tissue transformation the epithelial tissues underwent biochemical and structural changes that are manifested in the tissue fluorescence. To correlate the tissue morphology with the observed fluorescence differences in the fluorescence emission, animals were sacrificed and the tissue biopsies were subjected to histopathological evaluation. The fluorescence emission corresponding to different fluorophores was extracted from the EEM, and the spectral data were used in multivariate statistical algorithm for the earliest diagnosis of the onset of tissue transformation. The intrinsic fluorescence from tryptophan, NADH and prophyrins showed distinct differences in the spectral signature during the tissue transformation, due to the altered metabolic activities of the cells. The statistical analysis of the spectral data corresponding to each excitation wavelength showed better classification accuracy at 280, 320, 350 and 405 nm excitations, corresponding to tryptophan, collagen, NADH and porphyrins with the classification accuracy of 74.3, 68.1, 64.6 and 74.7 % respectively. The variations in the spectral signature and the results of the statistical analysis suggest that porphyrins, tryptophan and NADH can be targeted as potential tumor markers in the early detection of the tissue transformation process.

Proceedings Article | 15 April 2005 Paper

Photothermal and photochemical effects of laser light absorption by indocyanine green (ICG)

Mohammad Yaseen, Parmeswaran Diagaradjane, Brian Pikkula, Jie Yu, Michael Wong, Bahman Anvari

Proceedings Volume 5695, (2005) https://doi.org/10.1117/12.589702

KEYWORDS: Photodynamic therapy, Blood vessels, Absorption, Ear, Tissues, Photothermal effect, Indocyanine green, Collagen, Chromophores, Pulsed laser operation

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Indocyanine Green (ICG) is clinically used as a fluorescent dye for imaging purposes. Its rapid circulation kinetics and minimal toxicity has prompted investigation into ICG's utility as a photosentitizer for therapeutic applications. Traditionally, optically mediated tumor therapy has focused on photodynamic therapy, which employs a photochemical mechanism resulting from the absorption of low intensity CW laser light by localized photosensitizers such as Photofrin II, Benzoporphyrin Derivative (BPD), ICG. Treatment of cutaneous vascular malformations such as port-wine stains, on the other hand, is based on a photothermal mechanism resulting from the absorption of high intensity pulsed laser light by hemoglobin. In this study, we compared the effectiveness of combining photochemical and photothermal mechanisms during application of ICG in conjunction with laser irradiation with the intention that the combined approach may lead to a reduction in the threshold dose of pulsed laser light required to treat hypervascular malformations. The blood vessels in rabbit ears were used as an in vivo model for targeted vasculature. Irradiation of the ears with IR light (λ=785 nm, Δτ = 3 min, I_o = 120 mW) was used to elicit photochemical damage, while photothermal damage was brought about using pulses from a ruby laser (λ=694 nm, τ = 3 ms) with different fluences. For the combined modality, photochemical damage was induced first and followed by photothermal irradiation. This modality was compared with photothermal irradiation alone. The effectiveness of each irradiation scheme was assessed using histopathological analysis. We present preliminary data that suggests that pretreatment with photodynamic therapy before photothermal coagulation results in more severe vascular damage with lower photothermal fluence levels. The results of this study provide the foundation work for further exploration of the therapeutic potentials of photochemical and photothermal effects during application of ICG in conjunction with laser irradiation.

Showing 5 of 6 publications

Conference Committee Involvement (6)

Colloidal Quantum Dots/Nanocrystals for Biomedical Applications VI

22 January 2011 | San Francisco, California, United States

Colloidal Quantum Dots for Biomedical Applications V

23 January 2010 | San Francisco, California, United States

Colloidal Quantum Dots for Biomedical Applications IV

24 January 2009 | San Jose, California, United States

Colloidal Quantum Dots for Biomedical Applications III

19 January 2008 | San Jose, California, United States

Colloidal Quantum Dots for Biomedical Applications II

20 January 2007 | San Jose, California, United States

Showing 5 of 6 Conference Committees

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