A Novel Polyvinyl Alcohol/Salecan Composite Hydrogel Dressing with Tough, Biocompatible, and Antibacterial Properties for Infected Wound Healing

Polysaccharide-based wound dressings face challenges in mechanical properties and effective wound repair for infected wound surfaces. This study presents a novel polyvinyl alcohol (PVA)/Salecan (Sal) composite hydrogel dressing with high toughness, biocompatibility, and wound healing capabilities, developed using an interpenetrating polymer network strategy. The primary network was formed through electrostatic interactions between polydopamine (PDA) and biocompatible polysaccharide Salecan, followed by incorporation of AgNO₃, which was in situ reduced to silver nanoparticles within the hydrogel. PVA was introduced as a secondary matrix, further reinforcing the hydrogel network through cyclic freeze-thawing. The resulting hydrogel exhibited a tensile strength of 0.31 MPa, an elongation at break of 158.9%, and a toughness of 31.16 J·m^-2, demonstrating enhanced mechanical performance compared to both Salecan/PDA and previously reported Salecan/Fe³⁺ hydrogel. Co-culture experiments showed the hydrogel's strong antibacterial effects, inhibiting 80.1% of <i>Escherichia coli</i> (<i>E. coli</i>) and 99.5% of <i>Staphylococcus aureus</i> (<i>S. aureus</i>). Fibroblast culture tests confirmed its excellent cytocompatibility. In vivo studies on infected wounds showed nearly complete healing in the <i>S. aureus</i> + hydrogel group within 12 days. Quantitative immunohistochemical analysis of CD31 revealed that hydrogel treatment significantly upregulated CD31 expression, indicating enhanced neovascularization. Complementary Western blot analysis further demonstrated that hydrogel-treated groups exhibited a marked downregulation of pro-inflammatory factors alongside CD31 upregulation. In summary, the PVA/Sal-based hydrogel represents a valuable strategy for reducing inflammation and promoting regeneration in the management of infected wounds.