Biomimetic asymmetric Bletilla striata polysaccharide hydrogel with wet adhesion and antibacterial activity for active-passive treatment of infected wound

Developing biomimetic asymmetric wound dressings that mimic the structure and multifunctionality of natural skin remains challenging. Here, we report a natural polysaccharide-based asymmetric hydrogel (MP/AMBGZ) derived from Bletilla striata polysaccharide (BSP) via a facile one-pot, two-step strategy. Methacrylated BSP forms a biocompatible network, while gallic acid provides wet adhesion and antioxidant activity. ZnO nanoparticles incorporated into the inner layer enable Zn 2+ -mediated antibacterial activity and promote angiogenesis. Meanwhile, the outer MA-POSS layer forms a hydrophobic barrier that prevents bacterial adhesion. The hydrogel exhibits good mechanical properties, high swelling capacity, and excellent biocompatibility. In vitro studies demonstrate its cytocompatibility, antibacterial activity, hemostatic performance, and anti-inflammatory effects. In vivo experiments show rapid hemostasis and accelerated wound healing. In infected full-thickness wounds, MP/AMBGZ achieves near-complete closure within 14 days and promotes functional skin regeneration, including hair follicle formation. Overall, this work highlights the potential of BSP-based asymmetric hydrogels as multifunctional wound dressings for clinical applications.