Polycationic silk fibroin chelating nano-hydroxyapatite promotes angiogenesis for burn wound healing.

The regeneration of deep burn wounds, which cause dermal tissue necrosis, remains a significant clinical challenge. Herein, we report a skin dressing fabricated by integrating nano-hydroxyapatite (nHA) with a polycationic silk fibroin (CSF) to promote burn wound healing via enhanced angiogenesis. The nHA was firmly incorporated into the CSF matrix through metal-phenolic coordination, improving the mechanical robustness and stability of the composite. The CSF-nHA dressing significantly promoted the proliferation of NIH-3T3 fibroblasts and enhanced the recruitment and migration of human umbilical vein endothelial cells (HUVECs) in vitro. Furthermore, the dressing demonstrated a remarkable pro-angiogenic capacity, as validated by the tube formation assays. In a rat model with deep partial-thickness burns, treatment with the CSF-nHA dressing resulted in the formation of highly vascularized neo-tissue. This enhanced vascularization facilitated superior collagen deposition, tissue regeneration, and accelerated wound closure. This study combined inorganic nHA nanoparticles with bioactive CSF macromolecules, offering a promising strategy for the management of burn wounds by promoting rapid revascularization.