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

Cerium oxide nanoparticles (CeO₂ 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 CeO₂ 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.