Construction and function of robust and moist bilayer chitosan-based hydrogel wound dressing

The main limit of hydrogel used as an independent wound dressing is its poor water retention, brittleness, and weak skin adhesion. Focusing on it, the macromolecular cross-linked chitosan and polyacrylamide double network hydrogel (C-A) is chosen as a functional layer, another robust poly(vinyl alcohol)-polyacrylamide/glycerin (P-A) protective layer is designed to cover its surface, an interfacial reaction happens to link two layers tightly for achieving the function synergy. In this double-layer hydrogel (DH) dressing, the surface P-A layer with strong water locking ability could keep the wound surface moist for a long time, high strength and toughness make the dressing maintain integrity under large deformation and stress to strengthen wound protection, and the C-A layer with modest adhesion ensures the dressing fit the skin, the synergistic swelling ability could guarantee the fast absorption for the wound exudate. Moreover, in vitro and in vivo tests, the DH dressing exhibits excellent antibacterial and cytocompatibility, it could significantly accelerate skin tissue regeneration and wound closure than the commercial hydrocolloid dressings. In general, this DH dressing is easy to prepare and shows superior comprehensive performance, revealing the great potential for use as an independently applied wound dressing.