Selective monitoring and treatment of neuroblastoma cells with hydrogen sulfide activatable phototheranostic agent

Activity-based photosensitizers (aPSs) are highly attractive as they offer improved selectivity and better therapeutic outcome in the scope of photodynamic therapy (PDT). Here, a hydrogen sulfide (H2S) responsive iodinated resorufin-based PS (RHS) was developed to treat neuroblastoma cancer cells selectively. RHS was shown to be a phototheranostic agent as it turned on its fluorescence signal and singlet oxygen (1O2) generation capability after reacting with H2S. RHS exhibited remarkable sensitivity towards H2S and proved to be highly cytotoxic in H2S rich SH-SY5Y human neuroblastoma cells upon light irradiation. In contrast, no photocytotoxicity was observed in H2S deficient nonmalignant fibroblast L929 cells. RHS marks the first example of a resorufin-based H2S activatable phototheranostic agent, which paves the way for effective treatment of neuroblastoma through PDT modality.