(719e) Non-Porphyrin Photosensitizers for Photodynamic Therapy: Biophysical and Preliminary Cell Studies

Photodynamic therapy (PDT) is based on a photodynamic reaction involving a light-sensitive substance (a photosensitizer) combined with the irradiation by a beam light at a visible or near infrared (NIR) wavelength to destroy the target cells. The efficacy of PDT depends on the photosensitizer (PS) and the wavelength of irradiation of the laser light. Widespread research is on to optimize the potency of PDT and propose newer non-porphyrin based PS. In this work, we have compared the efficacy of riboflavin and coumarin-based fluorophore probes to serve as potential PS.

We have investigated the ability of amphiphilic coumarin to serve as a potent photosensitizer using biophysical studies. These fluorophores are amphiphilic in nature and were hypothesized to traverse the phospholipid membrane found in mammalian cells. Through this work, we have examined the possibility of these novel fluorophores to bind and internalize into cell membranes. Preliminary studies reveal that these fluorophores are toxic to the cancer cells and non-toxic to normal cells. Our results from biophysical studies, also suggest that these amphiphilic molecules successfully attach themselves to the cells thereby serving as a diagnostic and therapeutic tool. It is observed that, the degree of destabilization of cell membrane increased with increasing the carbon chain length on the tail group of the fluorophores. These results have been compared with internalization behavior of riboflavin monophosphate, a well know fluorophore and photosensitizer.