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 (H 2 O 2 ), 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 H 2 O 2 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 (MnO 2 ) nanoshells were coated to form a ZIF-67@AuNPs@MnO 2 nanoprobe. In the tumor microenvironment, MnO 2 depleted overexpressed GSH to produce Mn 2+ , and the bimetallic Co 2+ /Mn 2+ nanoprobe accelerated the Fenton-like reaction rate. Moreover, by catalyzing glucose via ultrasmall AuNPs, the self-supplying H 2 O 2 further promoted hydroxyl radical (˙OH) generation. Compared with those of ZIF-67 and ZIF-67@AuNPs, the ˙OH yield of ZIF-67@AuNPs@MnO 2 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@MnO 2 nanoprobe.