Dissecting the microenvironment around biosynthetic scaffolds in murine skin wound healing

Structural properties of biomaterials play critical roles in guiding cell behaviors and influence the immune response against them. We fabricated electrospun membranes with three types of surface topography (Random, Aligned, and Latticed). The aligned membranes showed immunomodulatory ability, and led to faster wound healing, reduced fibrotic response and enhanced regeneration of cutaneous appendages when used in skin wound repair. Based on that, we performed single-cell RNA sequencing analysis on cells from wounded mouse skin in the presence or absence of the Aligned scaffold. Keratinocytes, fibroblasts, and immune cells including neutrophils, monocytes, macrophages, dendritic cells, and T cells showed diverse cellular heterogeneity. More hair follicle progenitor cells, inner root sheath cells (anagen-related) and fibroblast subsets were found in the Aligned group, which corresponded to the improved regeneration of hair follicles and faster wound closure in the presence of scaffold. Immune responses towards the biomaterial differed from that of control group. In aligned samples, infiltrated macrophages and neutrophils were reduced, whereas more effector T cells were recruited. The time course of immune response was possibly advanced towards an adaptive immunity-dominant stage by the scaffold. The microenvironment around scaffold involved intricate interplay of immune cells and cutaneous cells, and wound healing was the comprehensive results of numerous influencing factors working together.