In Vitro Studies of Photosensitizer fluorescence changes on singlet oxygen mediated photobleaching

Abstract

Abstract:The effects of photosensitizer concentration on the singlet oxygen mediated photobleaching have been investigated in keratinocytes. Cells having different photosensitizers concentration were identified on the basis of the fluorescence signal amplitude and their fluorescence decay then studied to see if there was a correlation with concentration. The experimental results shows that the photobleaching was more rapid at the higher concentration as compared to lower concentration which mean that singlet oxygen plays a vital role in the rapid m-tetrahydroxyphenylchlorin (mTHPC) induced fluorescence photobleaching causing the sensitizer to degrade.

The Photosensitizer Temoporfin (mTHPC) – Chemical, Pre‐clinical and Clinical Developments in the Last Decade†‡

“…Moreover, changes in fluorescence behavior of temoporfin and changes in its absorption spectrum can be used to characterize the immediate surroundings of the photosensitizer (366,368,393,554). Analysis of temoporfin fluorescence in PDT investigations is closely associated with the photobleaching of the photosensitizer, where the photosensitizer is destroyed by photochemical reactions under illumination (42,(556)(557)(558). Photobleaching of temoporfin has been investigated in detail by Bonnett et al (559,560) and has been reviewed before (42).…”

“…Photobleaching of temoporfin has been investigated in detail by Bonnett et al (559,560) and has been reviewed before (42). In a series of publications, Atif reported on photobleaching studies in keratinocytes treated with PDT with temoporfin (554,557,558,561). These investigations found that photobleaching of temoporfin is increasing with the higher local concentrations of the photosensitizer (558).…”