Biomimetic asymmetric Bletilla striata polysaccharide hydrogel with wet adhesion and antibacterial activity for...

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 Zn²⁺-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.