Synthesis of CoSnS2 hollow nanocubes with NIR-enhanced chemodynamic therapy and glutathione depletion for combined cancer therapy

Low concentrations of endogenous hydrogen peroxide (H2O2) and intrinsic oxidative stress defense system greatly limited the efficiency of Fenton and Fenton-like reactions driven by a single metal element. Moreover, the complex physiological environment and inherent self-healing function of tumors make it difficult for chemodynamic therapy (CDT) alone, driven by Fenton and Fenton-like reactions, to eliminate malignant tumors. Herein, a tumor microenvironment (TME) remodeling cobalt-stannous sulfide CoSnS2 (CSS) hollow nanocubes are presented for photothermal therapy (PTT)-improved CDT, in which two redox pairs (Co2+/Co3+ and Sn2+/Sn4+) are involved in catalyzing H2O2 to generate a large number of toxic hydroxyl radicals (˙OH) resulting in massive apoptosis of tumor cells. Importantly, two redox pairs (Co2+/Co3+ and Sn2+/Sn4+) promoted the depletion of glutathione (GSH), which reduced tumor antioxidant capacity and thus enhanced the CDT therapeutic impact of CDT. Furthermore, the CDT efficiency was greatly improved by the excellent photothermal effect (η = 47.23%). The combination of PTT and CDT achieved good therapeutic effects, which may provide a new perspective for the development of other anti-tumor strategies on the basis of improved CDT and modulation of TME.