Gelatin-Based Injectable Hydrogels Loaded with Copper Ion Cross-linked Tannic Acid Nanoparticles for Irregular Wound Closure Repair

It is often difficult to close and repair irregular wounds such as gums with traditional dressings that have a fixed shape, while injectable hydrogels that can be molded in situ offer tremendous advantages in treating complex, large wounds and can better seal or fill a variety of irregular wounds. While the majority of injectable hydrogels developed in current research have poor mechanical properties and biocompatibility and obstacles to clinical applications, this paper reports an injectable hydrogel that can be molded in situ with appropriate mechanical properties, excellent biocompatibility, and antibacterial activity. Under UV irradiation, a methacrylate-gelatin/poly(vinyl alcohol) loaded with copper ion cross-linked tannic acid nanoparticle (GelMA/PVA-TA/Cu(2+)NPs) precursor solution could rapidly gel within 45 s and adhere stably to the wound tissue by topological adhesion and hydrogen bonding. Through hydrogen bonding and physical entanglement, TA/Cu(2+)NPs are anchored in the GelMA/PVA interpenetrating network to form the GelMA/PVA-TA/Cu(2+)NPs composite hydrogel. This injectable hydrogel, which can quickly achieve photocurable in situ molding, can not only achieve closure and repair of irregular wounds but also has appropriate swelling characteristics, absorbing tissue exudate and blocking bacteria, while providing a good moist environment for wounds and continuously promoting wound healing. Cytotoxicity tests and wound healing experiments have shown that GelMA/PVA-TA/Cu(2+)NPs injectable hydrogels have good biocompatibility and wound closure and repair ability and have promising applications in the treatment of irregularly wounded orifices.