Synthesis of BODIPY photosensitizers and their photodynamic effect on cancer cells

Abstract

Objective: To design and synthesize photosensitizers with different substituents and to identify its physicochemical characteritics and photodynamic effect on cancer cells. Methods: Two kinds of BODIPY photosensitizers BPOI and BPCI were synthesized through condensation reaction between aldehyde and reactive hydrogen of pyrrole, followed with electrophilic substitution reaction. Physicochemical properties were characterized by 1H NMR, FT-IR and UV-visible absorption spectra and fluorescence emission spectra. The ability to produce reactive oxygen species was detected by BPDF and DCFH-DA. Photodynamic therapy effect on rat glioma C6 cells in vitro was determined by MTT method. Results: Two kinds of BODIPY photosensitizers BPOI and BPCI were successfully synthesized with different substituents, which were confirmed by 1H NMR, FT-IR. Both materials had low toxicity and could be readily taken up by tumor cells. The ability of synthesized photosensitizers to produce reactive oxygen species was strongly influenced by solvent polarity when the substituent was electron-donating group, while no effect was found when the substituent was electron-withdrawing group. Conclusion: Photosensitizer BPOI with electron-donating substituent produces reactive oxygen species with a slow rate in a highly polar environment, while greatly enhanced this effect in a low polarity environment, which is expected to be used for environmental-selective photodynamic therapy in tumor cells.