Microenvironment-feedback hydrogel for precise sequential repair of acute infectious wounds

The healing of acute infected wounds is a multi-stage and sequential biological process. Traditional antibacterial dressings are usually a simple superposition of antibacterial properties and active ingredients, lacking effective coupling with the wound microenvironment, and it is difficult to accurately match the continuous process of infected wound healing. In this study, a pH-responsive hydrogel of sodium alginate and carboxymethyl chitosan interpenetrating network was constructed, and tannic acid (TA) and zinc-doped bioglass (BAG) were loaded through hydrogen bonding and hydrophobic interactions. In the acidic environment of infection, the enhancement of intermolecular non-covalent interaction leads to the contraction of hydrogel network and the rapid release of TA. In the alkaline environment of healing, the weakening of intermolecular interaction leads to the expansion of hydrogel network and the continuous release of Zn 2+ and Ca 2+ . In vitro biological evaluation showed that the hydrogel had an effective antibacterial effects against E.coli and S.aureus , and effectively regulated immune response. In addition, the hydrogel effectively removed excessive ROS and significantly increase the activity of cellular antioxidant enzymes, thereby accelerating the wound healing process in animal experiment. This microenvironment-responsive hydrogel provides a new therapeutic strategy for precise sequential repair of acute infectious wounds.