An NIR photothermal-responsive hybrid hydrogel for enhanced wound healing

Moderately regulating vascularization and immune microenvironment of wound site is necessary to achieve scarless wound healing of the skin. Herein, we have prepared an angiogenesis-promoting and scar-preventing band-aid with a core-shell structure, that consists of MXene-loaded nanofibers (MNFs) as the core and dopamine-hyaluronic acid hydrogel (H) as the shell (MNFs@V–H@DA) to encapsulate a growth factor (vascular endothelial growth factor, VEGF, abbreviated as V) and H₂S donor (diallyl trisulfide, DATS, abbreviated as DA). The continuous release of DA from this system produced H₂S, which would successfully induce macrophages to polarize into M2-lile phenotype, regulating the immune microenvironment and inhibiting an excessive inflammatory response at the wound sites. It is conducive to the proliferation of skin cells, facilitating the wound healing. In addition, an appropriate amount of VEGF can be released from the MXene nanofibrous skeleton by adjusting the time of near-infrared (NIR) light exposure, preventing excessive neovascularization and extracellular matrix deposition at the wound sites. Collectively, this NIR photothermal-responsive band-aid achieved scarless wound healing through gradient-controlled vascularization and a related immune sequential reaction of damaged skin tissue.