Document Server@UHasselt >
Research >
Research publications >

Please use this identifier to cite or link to this item: http://hdl.handle.net/1942/15201

Title: Modifying excitation light dose of novel photosensitizer PVP-Hypericin for photodynamic diagnosis and therapy
Authors: Penjweini, Rozhin
Loew, Hans G.
Eisenbauer, Maria
Kratky, Karl W.
Issue Date: 2013
Abstract: Conventional photodynamic diagnosis (PDD) and therapy (PDT) makes use of photosensitizers that are excited by continuous light irradiation of specific wavelengths. In the case of PDT, the overdose of continuous excitation may lead to an expansion of necrosis in cancer cells or morbidity in healthy surroundings. The present study involves 5-h fluorescence imaging of living human lung epithelial carcinoma cells (A549) in the presence of a novel photosensitizer, PVP-Hypericin (PVP: polyvinylpyrrolidone) to optimize the excitation light doses for PDD and PDT. A number of time-lapse imaging experiments were performed using a low-power blue LED operating in either continuous or pulsed mode. The irradiances I* were 1.59, 6.34 and 14.27 mW/cm(2), the pulse lengths L being 0.127, 1.29, 13, 54.5, 131 and 60,000 ms. Then, the relation between irradiance, various exposure times, photobleaching and phototoxicity of PVP-Hyperycin was investigated. Results showed a nonlinear relationship between the amounts of excitation dose, cell viability and toxicity. For all experimental I*, minimal phototoxicity and photobleaching was detected when cells were exposed to brief pulses of light (L <= 13 ms). On the other hand, pulsed excitation with I* = 14.27 mW/cm(2) and L = 131 ms induced high percentages of apoptosis comparable to the long exposures of L = 60,000 ms and the continuous excitation. Thus, replacement of continuous excitation by a pulsed method seems applicable for PDT. (C) 2013 Elsevier B.V. All rights reserved.
Notes: Univ Vienna, Fac Phys, A-1090 Vienna, Austria. Hasselt Univ, Biomed Res Inst, B-3590 Diepenbeek, Belgium. Med Univ Vienna, Dept Therapeut Radiol, A-1090 Vienna, Austria. Med Univ Vienna, Canc Res Inst, A-1090 Vienna, Austria.
URI: http://hdl.handle.net/1942/15201
DOI: 10.1016/j.jphotobiol.2012.12.013
ISI #: 000317882100016
ISSN: 1011-1344
Category: A1
Type: Journal Contribution
Validation: ecoom, 2014
Appears in Collections: Research publications

Files in This Item:

Description SizeFormat
artikel1.78 MBAdobe PDF

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.