Desing and synthesis of BODIPY based photosensitizers for photodynamic therapy

Abstract

Photodynamic therapy is a promising modality for the non-invasive treatment of several cancerous and non-cancerous diseases. PDT is more preferable than other therapies due to its low damage to non-targeted tissues and its controllable characteristics. The therapy involves the activation of a photosensitizer under light illumination to generate singlet oxygen which is the cytotoxic agent employed against the cancerous tissues. Thus, there is currently a great effort to develop various photosensitizers. Among these, BODIPY based photosensitizers are distinguished due to certain characteristics, including excellent photostability, high extinction coefficients and high resistance to photobleaching. In this study, we aimed to synthesize and develop new BODIPY based photosensitizers for the use of photodynamic therapy agents. BODIPY skeleton was devised using the dibromoethylene unit from the 2,6-positions in order to enhance the π-conjugation system for red shift to longer wavelengths resulting in a deep penetration of tissue. Heavy atoms such as bromine were introduced to the BODIPY core to ensure the transition from singlet states to triplet states via intersystem crossing for the generation of singlet oxygen. Photophysical properties and spectroscopic measurements of photosensitizers were performed successfully. Finally the photodynamic activities of photosensitizers in cancerous cells were also investigated.