An Antibacterial And Anti-inflammatory Hydrogel For Bacterial-infected Wound Healing

Bacterial infection will attack the wound,aggravate inflammation,impair angiogenesis at the wound site and block the transport of oxygen and nutrients necessary for wound healing,which is the main reason for the difficulty in wound healing.It is difficult to achieve the purpose of antibacterial activity and immunomodulation simultaneously with a single treatment method.Here,we reported an M2 macrophage-polarized anti-inflammatory hydrogel Gel/BP/Zn O with favorable antibacterial activity for the combined treatment of bacterial infection wounds.The cross-linked network of the hydrogel was composed of 6%(W/V)methacrylated gelatin(Gel MA)and 2%(W/V)oxidized dextran(o Dex),in which was loaded with black phosphorus(BP)nanosheets and zinc oxide nanoparticles(Zn O NPs).The hydrogel loaded with BP nanosheets and Zn O NPs exhibited the synergistic antibacterial activity of photothermal and zinc ions with an irradiation of 808 nm NIR laser.Meanwhile,trace zinc released from the hydrogel regulated the immune response in the wound microenvironment by manipulating the polarization of macrophages.A larger proportion of M2 macrophages secreted anti-inflammatory factors such as IL-4,TGF-β1,etc.and cytokines such as VEGF,which can promote cell proliferation and migration in wound repair and facilitate neovascularization.Under the combined treatment of photothermal stimulation and immune factors,more neovascularization and shorter inflammation appeared in infected full-thickness defect wounds of mouse skin,which greatly accelerated wounds closure.Therefore,the combined treatment of antibacterial activity and anti-inflammatory properties of hydrogel Gel/BP/Zn O+NIR is suggested to be a hopeful approach for bacterially infected chronic wounds.