Microenvironment-Adaptive Nanozyme for Accelerating Drug-Resistant Bacteria-Infected Wound Healing.

Reactive oxygen species (ROS) are favorable for antibacterial infection but their overproduction results in serious inflammatory response and aggravates the hypoxic state of the wound tissue, which is detrimental to healing stages of proliferation and remodeling. Here, an atomic-dispersion Fe-doped oxygen-deficient molybdenum oxide MoO 3- X (ADFM) bifunctional nanozyme, featuring implanted peroxidase-like and enhanced catalase-like activity, is developed for decomposing H 2 O 2 into strongly oxidizing hydroxyl radicals (•OH) for prevention of bacterial infection and into plentiful O 2 for healing stages. Therein, the introduction of Fe into MoO 3- X primarily produces an asymmetric electron density difference by elongating the bond length between metal atoms, synchronously stabilizing adsorption of •OH and weakening the adsorption of O 2 . ADFM also shows unimaginably high aqueous dispersity and pH-adaptive ROS regulation in the wound microenvironment, both of which are favorable for ADFM to fully exert enzyme-like activity for timely antibacterial and efficient wound-healing action. ADFM thus achieves efficient healing of drug-resistant bacteria-infected wounds in vivo, at an ultralow dosage of 30 µg mL -1 against 10 6 CFU mL -1 extended spectrum β-lactamases-producing Escherichia coli, exhibiting a wound-healing efficiency of ≈10 mm 2 per day, which sets a benchmark among these noble-metal-free nanozyme-based wound-healing agents.