Novel selenium-containing photosensitizers for near-infrared fluorescence imaging-guided photodynamic therapy

Benzopyran nitrile dyes cannot be used as qualified photosensitizers due to the low quantum yield of triplet state. The benzopyran derivatives containing selenium instead of oxygen atom based on the heavy atom effect are expected to become potential agents for photodynamic therapy. In this paper, a series of selenium-containing photosensitizers (PSX) were prepared according to this strategy. PSX can effectively produce both singlet oxygen and superoxide anions upon laser irradiation. PSX exhibited the emission wavelength at 500-800 nm and near-infrared (NIR) fluorescence imaging in HeLa cells. Excellent biocompatibility and phototoxicity further indicated that PSX could be used as efficient photosensitizers for NIR fluorescence imaging and photodynamic therapy.