Injectable Hydrogel Incorporated with Iron-Doped Carbon Dots Exhibiting Peroxidase-Like Activity for Antibacterial Therapy and Wound Healing

The increasing bacterial resistance highlights the necessity of developing superior antibacterial materials. Metal-doped carbon dots (CDs), a crucial branch of carbon-based nanozymes, exhibit efficient antibacterial properties using the reactive oxygen species (ROS) effect. In this study, iron-doped carbon dots (Fe-CDs) are synthesized with high peroxidase-like (POD-like) activity using natural hemin as a precursor for the first time. The formation of Fe-CDs remarkably improves the water solubility of hemin showing excellent biocompatibility. Additionally, iron is doped from hemin to the CDs surface, reducing the risk of trial-and-error associated with adding an external iron source. The Fe-CDs-hydrogel system is constructed via the incorporation of Fe-CDs into a dual-crosslinked injectable hydrogel, taking advantage of the synergistic effects. The system enhances the mechanical properties of hydrogel and serves as an excellent carrier for Fe-CDs. It exhibits effective antibacterial activity at low hydrogen peroxide (H 2 O 2 ) concentrations (10 −4 m ) via the activation of Fenton-like reaction-triggered POD-like catalytic activity and the electrostatic interactions. The system further demonstrates excellent healing efficacy in a bacteria-infected wound model by reducing inflammation levels and accelerating the regeneration of tissues. This study provides a novel approach for applying nanozymes in antibacterial therapy and wound healing.