Natural biopolymers derived hydrogels with injectable, self-healing, and tissue adhesive abilities for wound healing

Developing a biocompatible and multifunctional adhesive hydrogel with injectability and self-healing ability for promoting wound healing is highly anticipated in various clinical applications. In this paper, we present a novel natural biopolymer-derived hydrogel based on the aldehyde-modified oxidized guar gum (OGG) and the carboxymethyl chitosan (CMCS) for efficiently improving wound healing with the encapsulation of vascular endothelial growth factor (VEGF). As the hydrogels are synthesized via the dynamically reversible Schiff base linkages, it is imparted with excellent self-healing ability and good shear thinning behavior, which make the hydrogel be easily and conveniently injected through a needle. Besides, the physiochemical properties, including porous structure, mechanical strength and swelling ratio of the hydrogel can be well controlled by regulating the concentrations of the OGG. Moreover, the hydrogel can attain strong adhesion to the tissues at physiological temperature based on the Schiff base between the aldehyde group on the hydrogel and the amino group on the tissue. Based on these features, we have demonstrated that the VEGF encapsulated hydrogel can adhere tightly to the defect tissue and improve wound repair in the rat model of defected skin by promoting cell proliferation, angiogenesis, and collagen secretion. These results indicate that the multifunctional hydrogel is with great scientific significance and broad clinical application prospects.