Biodegradable Fe(III)@WS2-PVP Nanocapsules for Redox Reaction and TME-Enhanced Nanocatalytic, Photothermal, and Chemotherapy

In this study, biocompatible Fe(III) species-WS2-polyvinylpyrrolidone (Fe(III) @ WS2-PVP) nanocapsules with enhanced biodegradability and doxorubicin (DOX) loading capacity are one-pot synthesized. In this nanocapsule, there exists a redox reaction between Fe(III) species and WS2 to form Fe2+ and WO42-. The formed Fe2+ could be oxidized to Fe3+, which reacts with Fe(III) @ WS2-PVP again to continuously produce Fe2+ and WO42-. Such a repeated endogenous redox reaction leads to an enhanced biodegradation and DOX release of DOX @ Fe(III) @ WS2-PVP. More strikingly, the Fe2+ generation and DOX release are further accelerated by the overexpressed H2O2 and the mild acidic tumor microenvironment (TME), since H2O2 and H+ can accelerate the oxidation of Fe2+. The continuously generated Fe2+ catalyzes a fast Fenton reaction with the innate H2O2 in tumor cells and produces abundant highly toxic hydroxyl radicals for nanocatalytic tumor therapy. Together with the high photothermal transforming capability, the DOX @ Fe(III) @WS2-PVP nanocapsules successfully achieve the endogenous redox reaction and exogenous TME-augmented tumor photothermal therapy, chemo and nanocatalytic therapy outcome. The concept of material design can be innovatively extended to the synthesis of biodegradable Fe(III) @ MoS2-PVP nanocomposite, thus paving a promising novel way for the rational design of intelligent theranostic agents for highly efficient treatment of cancer.