Influence of different divalent ions cross-linking sodium alginate-polyacrylamide hydrogels on antibacterial properties and wound healing

Hydrogels are widely used as debriding agents on account of providing a moist environment for wound healing, however the lack of mechanical strength, angiogenesis and antibacterial property limits their applications. In this study, we synthesized novel divalent ion cross-liking hydrogels (copper, zinc, strontium and calcium) and compared the mechanical performance, swelling ratio, antibacterial properties and biocompatibility in vitro and vivo. Thereinto, among the four divalent ions cross-linked hydrogels, copper ion crosslinking exhibited the maximum breaking strength, while strontium and zinc ion cross-linked hydrogels exhibited an excellent mechanical strength. In addition, the swelling ratio and pore size of no-ion cross-linked hydrogels was larger than ion cross-kinked hydrogels. In vitro, the improvements on wound healing after hydrogel application were evaluated by histological and molecular assays by detecting VEGF and TGF-β expression. In vitro and in vivo study results showed that zinc cross-kinked hydrogel had a spectrum of antibacterial activities, cell viability, mechanical strength and the ability of wound closure by promoting fibroblasts migration, vascularization, collagen deposition and the formation of granulation tissue.