Near-infrared light-responsive on-demand puerarin-releasing injectable hydrogel for promoting healing of infected wounds.

Wound infection is a serious clinical challenge, often accompanied by persistent inflammatory response and the threat of increased bacterial resistance, there is an urgent requirement to develop a wound dressing with potent antimicrobial as well as immunomodulatory effects. In this study, we developed a multifunctional wound dressing to promote healing of infected wounds by doping puerarin-loaded mesoporous polydopamine nanoparticles into a carboxymethyl chitosan/sodium alginate oxide-based hydrogel. The hydrogel has good injectability, adhesion, and self-healing capabilities, and can be well matched to irregular wounds and against external injuries. The loaded PUE is rapidly released from the hydrogel in response to near-infrared (NIR) laser irradiation, which has a controlled release property. In addition, under NIR laser irradiation, the hydrogel with good photothermal properties exerted good antimicrobial properties through localized high temperature, and exhibited good antioxidant, immune microenvironment modulation, and pro-angiogenic effects through accelerated released PUE. In the E. coli-infected full-thickness skin wounds healing experiments, the hydrogel can effectively kill bacteria, regulate the immune microenvironment, promote collagen deposition and angiogenesis, and significantly accelerate the wound healing, showing promising applications.