Extracellular vesicle-integrated gelatin sponges enhance angiogenesis and cell migration in wound healing

Wound healing remains a major global burden on healthcare systems. Extracellular vesicle (EV)-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 the lack of effective delivery systems for preserving EV stability and bioactivity at the target site following administration. Herein, we present 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). The GS was 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 the incorporation of EVs into the GS preserved and supported their biological activities, particularly by enhancing keratinocyte migration, a key process in re-epithelialization during wound healing. The pro-angiogenic potential of the 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, the EV-integrated GS significantly promoted neovascularization, providing functional validation beyond conventional in vitro assays. These models provided 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.