Ligand-metal charge transfer and photothermal carbon dots synergistically enhance cerium dioxide nanozyme activity for diabetic infected wound healing

Cerium oxide nanoparticles (CeO 2 NPs), with intrinsic antioxidant, pro-oxidative activity under acidic conditions, and antibacterial properties, have been explored for diabetic wound therapy. However, their poor stability and limited catalytic efficiency remain major barriers. Here, we developed a facile strategy to anchor gallic acid (GA) onto CeO 2 NPs through metal–polyphenol coordination. This polyphenol shell markedly enhances nanoparticle stability and modulates the electronic structure via ligand–metal charge transfer, optimizing Ce valence states and oxygen vacancy ratios to boost nanozyme activity. To further improve therapeutic efficacy, photothermal carbon dots (CDs) with high light-to-heat conversion efficiency were incorporated. Beyond serving as photothermal agents, these CDs also exhibited intrinsic enzyme-like activities. In vivo, the resulting hybrid nanozyme accelerated diabetic wound healing by integrating antibacterial, antioxidant, anti-inflammatory, and immunomodulatory effects, while promoting epithelial regeneration and collagen deposition. This work highlights polyphenol–metal coordination as a versatile approach for stabilizing and optimizing metal-based nanozymes.