Natural gelatin / chitosan oligosaccharides / emodin eutectogels with multiple antibacterial effects for accelerated infected wound healing

Bacterial infections following skin injuries can lead to chronic, hard-healing wounds, and the overuse of antibiotics has made infection control a significant clinical challenge. Nature provides numerous antimicrobial agents, inspiring the design of novel antibacterial wound dressings; however, their solubility often presents additional hurdles. Herein, we leverage highly water-soluble chitosan oligosaccharide molecules dispersed within a gelatin-based gel network to overcome the poor solubility of chitosan, a known antibacterial agent. Notably, we first discovered that chitosan oligosaccharides can promote the solubility of poorly water-soluble antibacterial molecules like emodin through Schiff base reactions, thereby enabling synergistic antibacterial effects. The resulting eutectogel exhibits excellent antibacterial activity against both Staphylococcus aureus and Escherichia coli. Additionally, the gel demonstrates superior tensile strength, fracture strain, resistance to desiccation, and biocompatibility, with its outstanding overall performance laying a foundation for wound dressing applications. In animal models of infected wounds, the gel effectively accelerates wound healing, achieving wound closure rates of 166.9 % and 136.9 % of the control group on days 4 and 7, respectively. Mechanistic studies further reveal that the dressing promotes cellular proliferation, migration, and the regeneration of blood vessels and collagen, contributing to the wound healing process.