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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.