Fabrication and characterization of electrospun polycaprolactone/<i>Urechis unicinctus</i> derived-ECM composite scaffolds for small-diameter vascular grafts

Small-diameter vascular grafts (SDVGs; ≤6 mm inner diameter) often fail due to thrombosis, poor endothelialization, and low patency. To overcome these limitations, we developed electrospun composite scaffolds incorporating decellularized <i>Urechis unicinctus</i> ECM (UdECM), a marine invertebrate source rich in collagen, glycosaminoglycans, and elastin. UdECM was blended with polycaprolactone (PCL) at 1, 5, and 10 wt% and electrospun into fibrous matrices. We characterized scaffold hydrophilicity (water contact angle, water uptake), mechanical properties, and cell behaviors (<i>e.g.</i>, viability, proliferation, tube formation) using EA.hy926 endothelial cells, and performed <i>in vitro</i> blood clotting assays. UdECM-containing scaffolds exhibited improved hydrophilicity and mechanical strength compared to pure PCL, with the 10 wt% UdECM scaffold demonstrating the highest stiffness while retaining suitable elongation. Endothelial cells grown on UdECM-enhanced scaffolds showed increased viability and tube formation, indicative of a pro-angiogenic environment. Anticoagulant tests revealed reduced blood cell adhesion with higher UdECM content. These findings underscore the potential of marine-derived ECM to enhance the functionality of synthetic vascular grafts by promoting both endothelialization and thromboresistance.