Multifunctional Dual Ionic-Covalent Membranes for Wound Healing

Wound healing generally has four stages: hemostasis, inflammation, proliferation, and remolding. Most wound dressings only just take one or two phases into account. Herein, to develop a novel wound dressing that works at different stages, the blended alginate sodium/carboxymethyl chitosan membranes with a hydrogel-like structure are fabricated through a freeze-drying process together with a dual-ion (Sr²⁺ and Zn²⁺) cross-linking approach. The fabricated membranes show excellent properties in the swelling ratio, water vapor transmission rate, tensile strength, sustained release, cell adhesiveness, and biocompatibility, proving its general performance for application in wound healing. In particular, the membranes with optimal ion concentrations of 45 mM Sr²⁺ and 0.74 mM Zn²⁺ presented the antibacterial activity and accelerating function of wound healing. More specifically, the formation of epithelium and blood vessels is evidently advanced compared with a commercial dressing in vivo experiment, and the expression of main growth factors such as epidermal growth factor, basic fibroblast growth factor, vascular endothelial growth factor, and transforming growth factor is upregulated which also have good effects on the remolding of skin. The prepared wound dressings in this study have good effects on each stage of wound healing, which is important for the healing of chronic wounds. It provides more choices for wound healing, especially for chronic wound healing.