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Relationship Between mTHPC Fluorescence Photobleaching and Cell Viability During In Vitro Photodynamic Treatment of DP16 Cells ¶
Author(s) -
Dysart Jonathan S.,
Patterson Michael S.,
Farrell Thomas J.,
Singh Gurmit
Publication year - 2002
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2002)0750289rbmfpa2.0.co2
Subject(s) - photobleaching , viability assay , fluorescence , photodynamic therapy , in vitro , chemistry , biophysics , photochemistry , biochemistry , biology , optics , organic chemistry , physics
An implicit dosimetric model has been proposed in which biological damage caused by photodynamic therapy (PDT) is monitored through the decrease in sensitizer fluorescence during treatment. To investigate this, in vitro experiments were performed in which DP16 cells were incubated in meta ‐tetra(hydroxyphenyl)chlorin (mTHPC) and then irradiated with 514 nm light. Photosensitizer concentration, fluence rate and oxygenation were independently controlled and monitored during the treatment. Fluorescence of mTHPC was continuously monitored via a charge‐coupled device–coupled spectrometer during treatment and, at selected fluence levels, cell viability was determined using a trypan blue exclusion assay. The relationship of cell viability to normalized fluorescence was obtained for the different treatment conditions. The relationship was independent of cell medium oxygenation, treatment fluence rate and sensitizer incubation concentration except at a high mTHPC concentration (4 μg/mL). This relationship suggests that fluorescence bleaching may be used to predict mTHPC PDT damage in vitro.