Injectable and antibacterial ε-poly(l-lysine)-modified poly(vinyl alcohol)/chitosan/AgNPs hydrogels as wound healing dressings

A series of injectable and antibacterial hydrogels based on ε-poly (l-lysine)-modified poly (vinyl alcohol) (CPVA-g-EPL)/chitosan (CS)/Ag complexes was fabricated using oxidized dextran as a crosslinker. As-prepared hydrogels CPVA-g-EPL/CS exhibited swelling ratios of approximately 33.9–55.4 g g−1 and macroporous structure with average pore size of 54–102 μm in dry state. The concentration of bacteria (Escherichia. coli and Staphylococcus. aureus) after treating with hydrogels for 4 h decreased by four orders of magnitude compared with that after blank control treatment, indicating excellent antibacterial property. After adding Ag nanoparticles (AgNPs), the antibacterial activities of hydrogels (i.e., CPVA-g-EPL/CS/AgNPs) were further enhanced. Moreover, the prepared hydrogels possessed good biocompatibility against the mouse fibroblast. In a mouse skin defect model, histological examination showed increased thickness, integrity of the epidermal tissue and formation of the collagen fibers, implying that these hydrogels remarkably accelerated the wound healing process. Thus, this kind of injectable hydrogel can be a good candidate as wound healing dressings applied in wound therapy.