Injectable Double-Crosslinked Adhesive Hydrogels with High Mechanical Resilience and Effective Energy Dissipation for Joint Wound Treatment

Due to the moist environment and inevitable movement, efficient wound closure and healing of vulnerable joint skin remains a great challenge. Herein, a poly(gamma-glutamic acid)-crosslinked amino-functionalized PEGylated poly(glycerol sebacate) (gamma-PGA/PEGS-NH2) adhesive hydrogel is reported. PEGS-NH2 and gamma-PGA not only forms covalent amide bonds with biological tissue surfaces to achieve strong moist adhesion but also establishes a stable chemically crosslinked network in bulk hydrogels to resist deformation. Furthermore, bioinspired gallic acid-modified chitosan (CS-GA) is introduced to enhance moist adhesion via multiple hydrogen bonds and establish a dynamic physically crosslinked network to dissipate energy. Consequently, this adhesive hydrogel strongly adheres to moist biological tissue, showing an adhesion six times higher than that of fibrin glue and comparable to that of strong cyanoacrylate glue. Moreover, benefiting from high mechanical resilience and effective energy dissipation, 200 cycles of loading-unloading mechanical tests conducted under an adhesive state and a full-thickness rat skin incision model applied on a dynamic nape further confirmed the desirable dynamic tissue adhesion and wound healing performance. Combining the above ideal features with their good injectability and shape-adaptability to complex contours, such adhesive hydrogels are demonstrated to be promising candidates for joint wound closure and healing in moist and dynamic physiological environment.