Dr. Aliaksandr Karotki Profile

Dr. Aliaksandr Karotki

at Univ Health Network

SPIE Involvement:

Author

Publications (7)

Proceedings Article | 26 October 2007 Paper

Development and application of biological techniques to two-photon photodynamic therapy

Mamta Khurana, Aliaksandr Karotki, Eduardo Moriyama, Margarete Akens, Brian Wilson

Proceedings Volume 6796, 67960O (2007) https://doi.org/10.1117/12.778503

KEYWORDS: Photodynamic therapy, Blood vessels, In vivo imaging, In vitro testing, Confocal microscopy, Luminescence, Tissues, Sapphire lasers, Eye models, Microscopes

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Proceedings Article | 9 July 2007 Paper

Fluorescence from upper excited states of porphyrins with one- and two-photon excitation

M. Kruk, M. Drobizhev, A. Karotki, A. Rebane

Proceedings Volume 6727, 67272F (2007) https://doi.org/10.1117/12.752487

KEYWORDS: Luminescence, Absorption, Molecules, Optical amplifiers, Quantum efficiency, Spectroscopy, Zinc, Fluorescence spectroscopy, Molecular photonics, Atomic, molecular, and optical physics

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SPIE Journal Paper | 1 May 2007 Open Access

Complete blood vessel occlusion in the chick chorioallantoic membrane using two-photon excitation photodynamic therapy: implications for treatment of wet age-related macular degeneration

Kimberley Samkoe, Aisling Clancy, Aliaksandr Karotki, Brian Wilson, David Cramb

JBO, Vol. 12, Issue 03, 034025, (May 2007) https://doi.org/10.1117/12.10.1117/1.2750663

KEYWORDS: Blood vessels, Content addressable memory, Photodynamic therapy, Blood circulation, Blood, Tissues, Laser therapeutics, Quantum dots, Microscopes, Video

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Proceedings Article | 27 February 2007 Paper

Two-photon photodynamic therapy and its potential application to age related macular degeneration

Aliaksandr Karotki, Mamta Khurana, Stuart Bisland, Eduardo Moriyama, E. Rand Simpson, Melanie Campbell, Hazel Collins, Harry Anderson, David Cramb, Brian Wilson

Proceedings Volume 6427, 64270R (2007) https://doi.org/10.1117/12.701086

KEYWORDS: Photodynamic therapy, Blood vessels, Luminescence, In vitro testing, Absorption, In vivo imaging, Aluminum, Tissues, Oxygen, Visualization

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Proceedings Article | 8 September 2006 Paper

In vitro studies of the efficiency of two-photon activation of photodynamic therapy agents

Mamta Khurana, Aliaksandr Karotki, Hazel Collins, Harry Anderson, Brian Wilson

Proceedings Volume 6343, 634306 (2006) https://doi.org/10.1117/12.706554

KEYWORDS: Photodynamic therapy, In vitro testing, Femtosecond phenomena, Absorption, Continuous wave operation, Tissues, Microscopes, Luminescence, Sapphire lasers, Pulsed laser operation

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Proceedings Article | 14 October 2005 Paper

Two-photon excitation photodynamic therapy with Photofrin

Aliaksandr Karotki, Mamta Khurana, James Lepock, Brian Wilson

Proceedings Volume 5969, 596915 (2005) https://doi.org/10.1117/12.628132

KEYWORDS: Photodynamic therapy, Absorption, Luminescence, Femtosecond phenomena, Sapphire lasers, Photosensitizer targeting, Tissue optics, Oxygen, Continuous wave operation, Microscopes

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Proceedings Article | 12 October 2005 Paper

Singlet oxygen production by amphiphilic C60 derivatives and its correlation to cell cytotoxicity in vitro

Grace So, Aliaksandr Karotki, Sarika Verma, Tanya Hauck, Brian Wilson, Kenneth Pritzker, Long Chiang

Proceedings Volume 5969, 59690D (2005) https://doi.org/10.1117/12.629268

KEYWORDS: Oxygen, Fullerenes, Photodynamic therapy, Luminescence, In vitro testing, Melanoma, Absorption, Cancer, Materials science, Molecules

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Fullerene derivatives have appealing properties that can potentially be used in materials science and medical applications. In particular, fullerenes are known to produce reactive oxygen species upon their excitation with light. This makes them particularly attractive as photosensitizers for photodynamic therapy (PDT). Photodynamic therapy is a new modality of treatment of cancer as well as some non-cancerous conditions. It involves the combined actions of a drug (photosensitizer) and light to produce a cytotoxic effect. Water-soluble hexa(sulfo-n-butyl)[60]fullerenes (FC₄S) was reported recently to generate singlet oxygen (¹O₂) and superoxide radical (O₂^-·) upon its excitation with light, making it a promising candidate for PDT treatments. Recently, we synthesized new amphiphilic fullerene derivatives, namely, [60]fullerene-diphenylaminofluorene-oligo(ethylene glycol) conjugates, C₆₀(>DPAF-PEG600) and C₆₀(>DPAF-PEG2000), as potential photosensitizers. In this paper we compare FC₄S to PEG-based fullerenes in terms of their singlet oxygen photosensitization ability. We measured time-resolved kinetics of singlet oxygen luminescence photosensitized by excitation of fullerenes via a 10 ns pulsed laser at 523 nm. For FC₄S we observed "normal" kinetics with a monoexponential decay profile giving a time constant 3.8 us in water. In contrast, for the case of C₆₀(>DPAF-PEG600) and C₆₀(>DPAF-PEG2000), a non-monoexponential decay profile with a long tail (~ 10² μs) in water was observed. We hypothesize that this is due to formation of vesicles by PEG fullerenes in aqueous solution. To investigate photodynamic activity of these fullerene derivatives in vitro, we used HeLa human adenocarcinoma and B16 mouse melanoma cell lines. FC₄S showed clear photodynamic effects in both cell lines. The total fluence required to kill 50% of the cells at the drug concentration of 20 μM was 36 Jcm^-2 for HeLa cells and 72 Jcm^-2 for B16 cells. Neither PEG-based fullerene derivatives showed any appreciable photodynamic activity, possibly, due to low efficiency of singlet oxygen generation.

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