Construction of hyperbranched polylysine-modified antibacterial polyurethane foam dressings and their promotion of infected deep burn wound healing

Abstract

Foam dressings are vital for exuding wounds, yet antibacterial modification remains challenging and relies heavily on cytotoxic silver compounds. To address these challenges, in this study we developed a process for the antibacterial modification of polyurethane foam dressings using hyperbranched polylysine. The modification process consisted of a simple five-step procedure (soaking–drying–reacting–washing–drying) that did not compromise the foam's intrinsic properties, including hydrophilicity, pore structure, and mechanical performance. The optimized modified foam achieved above 99.9% killing of both methicillin-resistant Staphylococcus aureus and Escherichia coli under experimental conditions, competitive to the commercial silver-containing dressing. The HBPL-modified foam dressings also exhibited Grade 0 cytotoxicity and a hemolysis ratio below 1%, showing good biosafety far better than that of silver dressings. In an infected burn wound model in vivo, the modified foam dressings achieved complete wound closure within 21 d, similar to that of silver dressing. More importantly, the healing quality was significantly improved, including enhanced inflammation resolution, angiogenesis, and collagen remodeling. Given the convenience of operation and the success of modification, the method to prepare antibacterial foam dressings proposed here has great potential for applications in real world.