Biomimetic cellulose polysaccharide hydrogel with in situ "epidermal armor" for hemostasis, antimicrobial protection, and wound healing.

The skin serves as a critical barrier against infection and external damage. Effective wound management demands prompt hemostasis and infection control. Inspired by the hierarchical "epidermis-dermis" architecture of human skin, this work introduces a biomimetic bilayer hydrogel dressing. The hydrogel (named Fe@S/C) combines a dermis-mimetic layer of a double-crosslinked network of silk fibroin (Silk-GMA) and oxidized carboxymethyl cellulose (OXCMC-MA) with an in situ-formed epidermis-mimetic "Armor" antimicrobial protective layer via Fe3+ coordination. The hydrogel exhibits favorable mechanical flexibility and wet adhesion. It demonstrates excellent hemostatic efficacy, achieving rapid blood coagulation in vitro and in vivo. The hydrogel achieves a 96% bacterial reduction at 0.1 M Fe3+, as confirmed through in vitro assays and in vivo infection models. The hydrogel's electrical conductivity (0.566 S/m) and sensitivity (gauge factor = 1.17) enable real-time monitoring of physiological movements. Histological analysis reveals accelerated wound healing with reduced inflammation and organized collagen deposition. This strategy addresses key limitations of traditional dressings by integrating multiple functionalities, enhancing therapeutic outcomes, and offering a promising solution for advanced wound management.