Self‐Supply of O₂ and H₂O₂ by a Nanocatalytic Medicine to Enhance Combined Chemo/Chemodynamic Therapy

Abstract

Combined chemo/chemodynamic therapy is a promising strategy to achieve an improved anticancer effect. However, the hypoxic microenvironment and limited amount of H₂O₂ in most solid tumors severely restrict the efficacy of this treatment. Herein, the construction of a nanocatalytic medicine, CaO₂@DOX@ZIF-67, via a bottom-up approach is described. CaO₂@DOX@ZIF-67 simultaneously supplies O₂ and H₂O₂ to achieve improved chemo/chemodynamic therapy. In the weakly acidic environment within tumors, CaO₂@DOX@ZIF-67 is broken down to rapidly release the Fenton-like catalyst Co²⁺ and the chemotherapy drug doxorubicin (DOX). The unprotected CaO₂ reacts with H₂O to generate both O₂ and H₂O₂. The generated O₂ relieves the hypoxia in the tumor and further improve the efficacy of DOX. Meanwhile, the generated H₂O₂ reacts with Co²⁺ ions to produce highly toxic •OH through a Fenton-like reaction, resulting in improved chemodynamic therapy.