A glutathione and hydrogen sulfide responsive photosensitizer for enhanced photodynamic therapy

Photodynamic therapy (PDT) has been appeared as a promising clinical diagnosis and treatment for malignant tumor. However, its non-specific distribution and phototoxicity to normal tissues and skinspartially hinders the clinical applications of PDT in cancer diagnosis and therapy. Herein, 2,4-dinitrobenzenesulfonyl chloride, a commonly used quenching agent, is introduced to conjugate with 5,10,15,20-tetra(4-hydroxyphenyl)porphyrin for maximizing therapeutic effects and minimizing side effects of the photosensitizer. Owing to the conjugated 2,4-dinitrobenzenesulfonyl chloride, our designed photosensitizer TDBP can be activated by glutathione (GSH) and hydrogen sulfide (H2S) in solution and cancer cells, and then obtain recuperative fluorescence and photosensitive activity. Moreover, TDBP can achieve enhanced phototoxicity to GSH and H2S overexpressed cancer cells and reduced phototoxicity to normal cells and skins. Overall, the dual responsive photosensitizer developed here is a promising candidate for precisely therapy on GSH and H2S overexpressed cancer cells.