Ultrasmall gold decorated bimetallic metal–organic framework based nanoprobes for enhanced chemodynamic therapy with triple amplification

Chemodynamic therapy (CDT) has shown potential for important applications in tumor precision therapy, but insufficient endogenous hydrogen peroxide (H2O2), overexpressed glutathione (GSH) and a weak Fenton-reaction rate greatly reduced the efficacy of CDT. Herein, a metal-organic framework (MOF) based bimetallic nanoprobe with self-supplying H2O2 was developed for enhancing CDT with triple amplification, in which ultrasmall gold nanoparticles (AuNPs) were deposited on Co-based MOFs (ZIF-67), and manganese dioxide (MnO2) nanoshells were coated to form a ZIF-67@AuNPs@MnO2 nanoprobe. In the tumor microenvironment, MnO2 depleted overexpressed GSH to produce Mn2+, and the bimetallic Co2+/Mn2+ nanoprobe accelerated the Fenton-like reaction rate. Moreover, by catalyzing glucose via ultrasmall AuNPs, the self-supplying H2O2 further promoted hydroxyl radical (˙OH) generation. Compared with those of ZIF-67 and ZIF-67@AuNPs, the ˙OH yield of ZIF-67@AuNPs@MnO2 obviously increased, due to which the cell viability decreased to 9.3%, and the tumor completely disappeared, indicating the enhanced CDT performance of the ZIF-67@AuNPs@MnO2 nanoprobe.