Advanced Polyurethane Foam-Based Hybrid Dressing with Controlled Release of Silver Ions for Treating Infected Wounds

Wound infections impede healing and account for nearly half of chronic wound cases (∼6.7 million people), posing significant clinical and economic burdens on healthcare. Antibiotics treat infections, but their misuse has accelerated antimicrobial resistance. A holistic approach to wound infection management includes exudate handling, potent antibacterial activity, mitigating multidrug resistance, regulating therapeutic release, and promoting healing. However, existing therapeutic options remain insufficient to address wound healing's multifactorial nature. This study presents silver ion (Ag⁺) exchange-based hybrid dressing formulated from an aliphatic diisocyanate-based prepolymer instead of conventional diisocyanates, biocompatible foaming agents, and a crosslinker-free hyaluronic acid coating. According to BS EN 13726 and ASTM D3574-17 standards, the dressing showed excellent exudate handling capacity, burst and sustained release of Ag⁺, and comfort wear characteristics. Despite low Ag⁺ concentrations (40-60 wt.%), the dressing demonstrated excellent antimicrobial efficacy (>99%) against Staphylococcus aureus and its drug-resistant strain in in vitro and in vivo studies, comparable to a leading commercial dressing (Biatain). In a full-thickness S. aureus-infected Wistar rat model, the dressing facilitated complete wound closure by day 18 and enhanced tissue regeneration, as evidenced by hematoxylin and eosin staining, Masson's trichrome, and immunohistochemical evaluations. Overall, dressings regulate infection and expedite healing, underscoring their significance in clinical wound care.