The antibacterial and hemostatic activity of Gastrodia elata polysaccharide-based hydrogel embedded with drug-carrying microspheres accelerates diabetic wound healing

The emergence of chronic diabetic wounds can cause skin bleeding and wound infection, which will be lifethreatening in severe cases. Developing an effective dressing that quickly stops bleeding, reduces bacterial infection, and promotes wound healing is a crucial strategy for treating diabetic wounds. Here, we prepared a Gastrodia elata polysaccharide (GEP)-based hydrogel for type 2 diabetic skin wound healing. Gastrodin (GAS) was firstly grafted onto the chitosan (CS) skeleton through a free radical grafting method, and then mixed with oxidized Gastrodia elata polysaccharide (OGEP) to obtain a novel hydrogel. Afterward, epigallocatechin gallate (EGCG)-coated microspheres were added to the above hydrogel. The characterization of the composite hydrogel showed good porosity, degradability, and rheological properties, as well as excellent antibacterial, antioxidant, and hemostatic activities, which suggested that it could be used as a good wound dressing. Therefore, we used it for diabetic wound healing in mice. It showed that the novel composite hydrogel could significantly accelerate chronic wound healing in a high-sugar environment. Combined with the pathological analysis and in vitro experiment, we believed that the mechanism of the hydrogel accelerating wound healing was related to promoting angiogenesis, reducing the expression of inflammatory factors, promoting skin collagen deposition, and increasing tissue remodeling. All results indicated that this novel hydrogel had great potential in chronic diabetic wound repair.