A novel hydrogel with inherent antibacterial and hemostatic properties for burn wound healing.

The skin is the immune system's first line of defense. Extensive skin burns can lead to tissue necrosis, sepsis, and even death. Anti-infectious care of burn wounds is a major challenge in clinical medicine. However, the extensive use of antibiotics led to the emergence of multi-drug-resistant bacteria and silver dressings with antibacterial effects are also cytotoxic. We used the natural cationic antibacterial agent ε-polylysine (EPL) to graft Epigallocatechin-3-gallate (EGCG) to synthesize EPL-EGCG. Then, we used methacrylated gelatin (GelMA) with arginine-glycine-aspartate-rich acid (RGD) sequence and EPL-EGCG form interpenetrating polymer network hydrogels with excellent swelling properties. The hydrogel's inherent antibacterial properties and photo-cross-linking properties can cover irregular burn wounds and isolate bacteria to prevent infection. In addition, we used polydopamine (PDA) to coat GelMA microspheres with excellent hemostatic efficacy and load platelet-rich plasma (PRP) to enhance the hemostatic efficacy of the microspheres and impart inflammation-regulating functions. The hydrogel showed excellent hemostatic efficacy in rat liver injury and tail vein injury models. In the rat infected burn model, the hydrogel exhibited favorable antimicrobial, pro-angiogenic, and anti-inflammatory phenotype polarization of macrophages. Our study shows that GelMA/EPL-EGCG/GM-PDA@PRP hydrogel application has excellent antibacterial, hemostatic and anti-inflammatory effects, providing a new treatment strategy for wound care before burn skin grafting.