Tri-layer hydrogel scaffold supporting co-culture paracrine signaling for accelerated skin repair

Abstract

The clinical management of complex skin wounds still lacks biomaterials that provide mechanical stability, pro-angiogenic signaling, and rapid tissue integration in a single platform. We engineered a tri-layer scaffold consisting of electrospun polycaprolactone fibers for initial structural support, a fibrin hydrogel for cell adhesion, and an alginate shell that creates a mildly hypoxic, nutrient-permissive niche. Co-seeding the scaffold with adipose-derived stem cells (ADSCs) and human umbilical vein endothelial cells (HUVECs) maintained high cell viability, strengthened paracrine crosstalk, and up-regulated genes involved in extracellular-matrix remodeling and angiogenesis in vitro. In a mouse dorsal-wound model the cell-laden construct accelerated closure, rebuilt a well-stratified epidermis and dermis, and generated dense microvascular networks compared with scaffold-only and single-cell controls. Histology confirmed organized collagen deposition with strong laminin and involucrin expression, indicating mature skin regeneration. The scaffold also displayed high swelling capacity, allowing it to conform to dynamic wound beds while managing exudate. These results show that a mechanically tuned tri-layer scaffold integrated with stem–endothelial co-culture can coordinate angiogenesis and tissue repair, supporting its potential for treating difficult cutaneous wounds.