Novel phenothiazine-based amphiphilic Aza-BODIPYs for high-efficient photothermal therapy

Photothermal therapy (PTT) is one of innovative therapeutics types that have been widely applied in cancer treatment, antibiosis and insecticide. It is of significance to investigate photothermal conversion agents (PCAs) with outstanding photothermal conversion ability, photostability and biocompatibility. Here, we developed three novel phenothiazine-based aza-BODIPYs for high-efficient PTT applications. Phenothiazine, as the electron-donating moiety, was introduced into aza-BODIPY core to achieve red-shifted absorption band (∼20–40 nm) with λmax at 730–745 nm and high molar extinction efficient (105 M−1 cm−1). TEG linker was decorated for further increasing the hydrophilicity and biocompatibility of aza-BODIPYs. After self-assembly, the nanoparticles exhibited the preferable photothermal conversion efficient (53–63%) and high photostability with the appropriate hydrated sizes (60–110 nm) and homogenous morphologies. Finally, the aza-BODIPY nanoparticles can significantly decrease the HeLa cell viability under 808 nm laser irradiation, but have the negligible cytotoxicity in dark environments. The series of phenothiazine-based aza-BODIPY PCAs have much potential for the more applications of clinic photothermal therapy in future.