One-Pot Approach to Fe²⁺ /Fe³⁺ -Based MOFs with Enhanced Catalytic Activity for Fenton Reaction

Smart theragnostic nanoplatforms exhibit great promise in clinical tumor treatment. The Fe-based Fenton reaction in tumor sites may generate reactive oxygen species to kill cancer cells with negligible side effects on normal tissues. However, its efficiency and duration are limited by the low intracellular concentration of H₂ O₂ , weak acidicity of tumor tissue, and low catalytic activity of conventional Fenton reagents. Herein, a facile strategy is proposed to efficiently overcome these obstacles. An efficient enzymatic/Fenton-starvation nanoreactor PMs loaded with glucose oxidase and perfluoropentane (PGPMs) is constructed through synthesizing methoxy-PEG-carboxymethy-modified iron (Fe²⁺ /Fe³⁺ )-based metal-organic frameworks (PMs), followed by loading glucose oxidase (GOx) and perfluoropentane (PFP). PGPMs accumulating in the tumor tissue exhibit tumor microenvironment-responsive biodegradable behavior and unusual catalytic activity for Fenton reaction advantageous over Fe³⁺ -based MOFs. Meanwhile, encapsulation of GOx into PGPMs further significantly increases the catalytic activity for Fenton reaction and also induces starvation therapy. PGPMs also exhibit considerable capabilities of ultrasound and tumor microenvironment-responsive T2 MR imaging applicable for contrast-enhanced diagnosis. Both in vitro and in vivo studies demonstrate the great diagnostic and therapeutic potentials of this nanoreactor in tumor.