Injectable Photothermal PDA/Chitosan/β‐Glycerophosphate Thermosensitive Hydrogels for Antibacterial and Wound Healing Promotion

Controlling infections while reducing the use of antibiotics is what doctors as well as researchers are looking for. As innovative smart materials, photothermal materials can achieve localized heating under light excitation for broad‐spectrum bacterial inhibition. A polydopamine/chitosan/β‐glycerophosphate temperature‐sensitive hydrogel with excellent antibacterial ability is synthesized here. Initially, the hydrogel has good biocompatibility. In vitro experiments reveal its noncytotoxic property when cocultured with gingival fibroblasts and nonhemolytic capability. Concurrently, the in vivo biocompatibility is confirmed through liver and kidney blood markers and staining of key organs. Crucially, the hydrogel has excellent photothermal conversion performance, which can realize the photothermal conversion of hydrogel up to 3 mm thickness. When excited by near‐infrared light, localized heating is attainable, resulting in clear inhibition impacts on both Staphylococcus aureus and Escherichia coli, with the inhibition rates of 91.22% and 96.69%, respectively. During studies on mice's infected wounds, it is observed that the hydrogel can decrease S. aureus’ presence in the affected area when exposed to near‐infrared light, and also lessen initial inflammation and apoptosis, hastening tissue healing. These findings provide valuable insights into the design of antibiotic‐free novel biomaterials with good potential for clinical applications. Photothermal temperature‐sensitive hydrogels using polydopamine as a photothermal agent are synthesized to achieve heating under near‐infrared (NIR) light excitation. On the basis of good biocompatibility, bacteriostatic effect without antibiotic addition under NIR light excitation can be realized and healing of infected wounds is accelerated.