Extracellular Vesicle-Integrated Gelatin Sponges Enhance Angiogenesis and Cell Migration in Wound Healing

Abstract

Wound healing remains a major global burden on healthcare systems. Extracellular vesicles (EVs)-based therapies have emerged as promising cell free approaches due to their ability to deliver bioactive cargo. However, their clinical transition is largely limited by lack of the effective delivery systems for preserving EV stability and bioactivity at the target site following administration. Herein, we present a clinically relevant, biocompatible and biodegradable gelatin sponges (GS) as a functional biomaterial platform for EVs derived from rat bone marrow mesenchymal stromal cells (rt‑BM‑MSCs). GS were fabricated via glutaraldehyde crosslinking followed by lyophilization to obtain a stable and highly porous architecture suitable for EV loading. This intrinsic porous structure enabled efficient EV loading and incorporation within the scaffold. Biological function assays demonstrated that incorporation of EVs into GS preserved and supported their biological activity, particularly by enhancing keratinocyte migration, a key process in re-epithelization during wound healing. Pro-angiogenic potential of EV‑integrated GS was further evaluated using ex vivo aortic ring and ex ovo Chorioallantoic Membrane (CAM) assays, which mimic microvascular sprouting and functional vascular network, respectively. In both models, EV-integrated GS significantly promoted neovascularization, providing functional validation beyond conventional in vitro assays. These models provide physiologically relevant evidence of vascularization, a key process underlying granulation tissue formation and wound repair. Importantly, GS integration enhanced EV efficacy indicating that the biomaterial microenvironment actively modulates EV bioactivity and improves angiogenic outcomes.