AuPt Nanoparticle-Based Injectable Hydrogel as Cascade Nanozyme for Accelerating Bacteria-Infected Wound Healing

Bacterial infections have been the main obstacle of wound healing in clinic. Conventional antibiotics have been widely used for bacterial infections therapy. However, the misuse and long-term use of antibiotics could induce drug resistance, resulting in the reduced antibacterial effect. Recently, the nanozyme-based combination therapy mode has emerged as a promising strategy to achieve enhanced antibacterial effect with different antimicrobial mechanisms. Inspired by this, a gold/platinum nanoparticle-based injectable hydrogel with nanozyme and photothermal properties was developed for accelerating bacteria-infected wound healing. In detail, gold/platinum nanoparticles (AuPt NPs) were prepared by reducing metal precursors in the presence of ascorbic acid. Then, AuPt NPs and GOx were incubated with thiol-terminated four-arm polyethylene glycol to form injectable AuPt/GOx gel. The AuPt/GOx gel possessed a cascade catalytic activity: GOx converted glucose into gluconic acid and hydrogen peroxide (H2O2) and subsequently promote peroxidase-like reaction of AuPt NPs to transfer H2O2 into a more toxic hydroxyl free radical for destroying bacteria. More than that, AuPt/GOx gel displayed a good photothermal effect. The wound healing rate in AuPt/GOx gel + glucose + NIR group was the fastest, which is attributed to the synergistic effect of nanozyme activity and photothermal effect. This work provides a safe and robust strategy for bacterial infection therapy.