Construction of multifunctional hydrogel based on the tannic acid-metal coating decorated MoS dual nanozyme for bacteria-infected wound healing.

Bacterial infection, tissue hypoxia and inflammatory response can hinder the infected wound repair process. To mitigate the above issues, tannic acid-chelated Fe-decorated molybdenum disulfide nanosheets (MoS@TA/Fe NSs) with dual enzyme activities were developed and anchored to a multifunctional hydrogel. The hydrogel exhibited excellent antibacterial ability owing to the combined effects of photothermal therapy (PTT), glutathione (GSH) loss, and the peroxidase (POD)-like activity (catalyse HO into ·OH under acid condition) of MoS@TA/Fe NSs. Benefitting from the catalase (CAT)-like activity, the hydrogel could decompose HO into O at neutral pH to relieve hypoxia and supply adequate O. POD-like activity was mainly attributed to MoS NSs, while CAT-like activity was primarily due to TA/Fe complex. Moreover, MoS@TA/Fe NSs endowed the hydrogel with outstanding anti-oxidant ability to scavenge redundant reactive oxygen species (ROS) and reactive nitrogen species (RNS) under neutral environment to maintain the balance of antioxidant systems and prevent inflammation. In addition, the hydrogel could inhibit the release of inflammatory factors for the anti-inflammatory property of TA. TA retained partial phenolic hydroxyl groups, which cross-linked the nanosheets to the network structure of the hydrogel and promoted the adhesion of hydrogels. Due to the dynamic boron ester bonds between polyvinyl alcohol (PVA), dextran (Dex), MoS@TA/Fe, and borax, the hydrogel demonstrated fast self-healing and rapid shape adaptability. This shape-adaptable adhesive hydrogel could fill the whole wound and closely contact the wound, ensuring that it achieved its functions with maximum efficiency. The MoS@TA/Fe nanozyme-anchored multifunctional hydrogel showed high potential for bacteria-infected wound healing.