Chitosan-based Janus dressing with asymmetric wettability for rapid hemostasis, antibacterial protection, and tissue regeneration in hemorrhagic wound management

Multifunctional wound dressings with rapid hemostasis, infection prevention, and tissue regeneration are crucial for treating hemorrhagic wounds. Inspired by the heterogeneous interfacial structure of natural skin, this study developed a chitosan(CS)-based Janus wound dressing with asymmetric wettability. The inner layer consists of methacrylated chitosan (CSMA), incorporating polydopamine-coated silica (PDA-SiO₂) nanoparticles to form a hydrophilic sponge with hemostatic, antioxidant, and pro-angiogenic properties. The outer layer is a thermoplastic polyurethane (TPU) nanofiber membrane integrated with antibacterial agent zeolitic imidazolate framework-8 (ZIF-8), creating a hydrophobic barrier to prevent bacterial invasion. In vitro tests confirmed effective bacterial resistance, while hemostasis assays demonstrated enhanced platelet and red blood cell aggregation, accelerating coagulation. In vivo evaluations using rat liver injury and tail amputation models confirmed superior hemostatic performance, with blood loss reduced by 0.44 g and 0.23 g, respectively, and bleeding time shortened by 41.52 s and 59.47 s compared to Gauze. Furthermore, in full-thickness skin wound models, accelerated healing was achieved through infection prevention, increased collagen deposition (20.82 % higher than Control), and stimulated angiogenesis (3.10 % higher CD31 expression). These findings highlight CM@PS/TZ as a promising Janus dressing integrating antibacterial activity, hemostasis, and pro-angiogenic effects, offering an innovative solution for hemorrhagic wound treatment.