Luminal surface design of electrospun small-diameter graft aiming at in situ capture of endothelial progenitor cell.

If endothelial progenitor cells (EPCs), which circulate in blood flow, are captured on the luminal surface of an implanted artificial graft and sooner or later proliferate to form a fully endothelialized surface, such a small-diameter artificial graft must exhibit a high patency rate. This study aimed at designing a luminal surface of elastomeric electrospun mesh graft, which is capable of selective capture of EPCs under arterial flow and has a high antithrombogenic potential until full endothelization is achieved. The designed luminal surface layer is composed of a photopolymerized gelatin gel layer that enables the release of impregnated heparin and selective adhesion of circulating EPCs via complexation between surface-fixed vascular endothelial growth factor (VEGF) and cellular VEGF receptor. Human mononuclear cells seeded and cultured on such a gel layer expressed endothelial cell surface markers. Confocal laser scanning microscopy observation revealed that VEGF is highly surface-enriched, and heparin is homogeneously distributed in the gel layer. A continuously slow release of heparin was observed. Thus, a prototype luminal surface was fabricated on electrospun segmented polyurethane tubes for in vivo study.