Shark skin and mussel-inspired polyurethane hydrogel sponge for wounds with infection and exudate

Inspired by the antifouling properties of shark skin and the bioadhesion of mussels, our study presents a three-layer biomimetic wound dressing with hierarchical wettability and rapid exudate drainage capabilities. The shark skin-inspired hydrophobic modified polyurethane (PU) sponge provides antifouling properties and serves as a bacterial barrier. The mussel-inspired dopamine-functionalized carboxymethyl chitosan hydrogel (CMCS-DOP) absorbs exudates and forms an in situ hydrogel, effectively capturing and eliminating bacteria. The porous sponge layer in direct contact with the wound facilitates rapid exudate drainage, preventing excessive wound hydration. This hierarchical structure coordinates exudate transport and bacterial removal. The fabricated PCD hydrogel sponge dressing (PCD dressing) exhibits a wettability transition (contact angle: 3°-35°-101°) and a water vapor transmission rate of 1021-797-691 g/m². It demonstrates potent bactericidal effects against Staphylococcus aureus and Escherichia coli, with survival rates of only 13 % and 14 %, respectively, and bacterial-blocking efficiencies of 89 % and 94 %. In a chronic bacterial infection wound model, the PCD dressing outperforms conventional clinical dressings, increasing the wound healing rate by 25.8 %, reducing inflammation, and enhancing angiogenesis and collagen deposition. Notably, the PCD mitigates oxidative stress at the wound site by regulating the polarization of anti-inflammatory macrophages. This exudate-draining and responsive dressing offers a promising strategy for promoting the healing of wounds with high exudate levels.