Core-shell Structure manganese-containing Nanozyme Hydrogel for Skin Injury Repair by Remodeling Microenvironment

Skin injury is a common pathological disaster; the common causes are cuts, scratches, burns, and so on. Blood vessels will be damaged and lose their normal functions. Finally, cellular apoptosis, tissue fibrosis, scar formation, and tissue dysfunction may happen. The generation of reactive oxygen species (ROS) and inflammatory responses following skin damage worsen the injury. Therefore, a novel skin patch Mn3O4@PDA/VEGF/PAM-HA was designed in this experiment to remove ROS, resist inflammation, and promote vascular reconstruction. In this work, the mechanical properties of the biomaterial mimicked the human skin, and the morphology provided the 3D structure for human skin tissue. In vitro, the biomaterial had good biocompatibility and did not result in toxicity to human umbilical vein endothelial cells (HUVEC) at suitable concentrations. We further verified the material's excellent ROS-scavenge and anti-inflammation abilities by fluorescence and probe, especially in HUVEC cells and macrophages. The result showed that cellular oxidative stress of HUVEC cells had decreased, and a large percentage of macrophage's phenotype had changed to M2. By supplementing vascular endothelial growth factor (VEGF), HUVEC could proliferate rapidly after injury, accelerating the regeneration of blood vessels and promoting the metabolism and nutrient exchange after injury. This multifunctional patch showed an excellent ability to anti-inflammation, ROS scavenging, and promote vascular regeneration, offering a new approach to skin damage repair.