Thermoresponsive in Situ Forming Hydrogel with Sol-Gel Irreversibility for Effective Methicillin-Resistant Staphylococcus aureus Infected Wound Healing

An in situ forming hydrogel has emerged as a promising wound dressing recently. As physically cross-linked hydrogels are normally unstable, most in situ forming hydrogels are chemically cross-linked. However, big concerns have remained regarding the slow gelation and the potential toxicity of residual functional groups from cross-linkers or the polymer matrix. Herein, we report a sprayable in situ forming hydrogel composed of poly(N-isopropylacrylamide(166)-co-n-butyl acrylate(9))-poly(ethylene glycol)-poly(N-isopropylacrylamide(166)-co-n-butyl acrylate(9)) copolymer (P (NIPAM(166)-co-nBA(9))-PEG-P (NIPAM(166)-co-nBA(9)), denoted as PEP) and silver-nanoparticles-decorated reduced graphene oxide nanosheets (Ag@rGO, denoted as AG) in response to skin temperature. This thermoresponsive hydrogel exhibits intriguing sol-gel irreversibility at low temperatures for the stable dressing of a wound, which is attributed to the inorganic/polymeric dual network and abundant coordination interactions between Ag@rGO nanosheets and PNIPAM. The biocompatibility and antibacterial ability against methicillin-resistant Staphylococcus aureus (MRSA) of this PEP-AG hydrogel wound dressing are confirmed in vitro and in vivo, which could transparently promote the healing of a MRSA-infected skin defect.