Spatially heterogeneous epidermal growth factor release from microporous annealed particle (MAP) hydrogel for improved wound closure.

Microporous annealed particle (MAP) hydrogel has been a promising scaffold platform technology to promote immediate tissue integration in injured tissue environments. The addition of growth factors has the potential to accelerate tissue integration and enhance scaffold-mediated healing. Growth factor releasing scaffolds face the translational hurdle of limited solubilized protein shelf stability; however, to address this hurdle we present a lyophilized MAP scaffold which can be effectively rehydrated directly prior to use. Our new approach includes a heterogenous MAP scaffold wherein 5% of the microgels contain immobilized heparin loaded with epidermal growth factor (EGF) at 1 μg mL. We demonstrate that these scaffolds, which are directly loaded with EGF following lyophilization maintain equivalent properties to scaffolds loaded passively diffusion into water-swollen microgels, including EGF release profiles and cell migration studies that did not significantly differ. Further, these heterogeneous scaffolds exhibit a significant increase in cellular migration and quicker re-epithelialization . This progress on spatially heterogenous growth factor release from MAP scaffolds has great potential to improve complex wound treatment and advance the field of growth factor releasing scaffolds.