Food-borne melanoidin-based nanozyme mimics natural peroxidase for efficient catalytic disinfection

Nanozymes show great potential as broad-spectrum antibacterial agents in the field of anti-infection. Their feasibility of application has received great hindrance due to low catalytic performance, insufficient reactive oxygen species (ROS), complex material design, and biosafety issues. Herein, we discovered an Fe³⁺-centered Melanoidin/Fe³⁺ nanozyme that exhibited superior reaction rate and catalytic activity to horseradish peroxidase (HRP) through the carboxyl, nitrogenous structure of Melanoidin. Melanoidin/Fe³⁺ catalyzed the formation of hydrogen peroxide (H₂O₂) into highly toxic superoxide anion (O₂^-•), which promoted the antibacterial ability of H₂O₂. The results showed that Melanoidin/Fe³⁺ had an excellent antibacterial effect against methicillin-resistant Staphylococcus aureus (MRSA) in low concentration H₂O₂ system. Both the infection wound model experiment and the biocompatibility experiment showed that the Melanoidin/Fe³⁺ promoted wound healing and had impressive biosafety. Thus, Melanoidin/Fe³⁺ shows ideal promise for the design of artificial enzymes with catalytic properties comparable to those of natural enzymes and clinical antibacterial therapy.