Rapid Endothelialization Enabled by Integrating Bi-oriented Topography and Salvianolic Acid B Modification on a Small-Diameter Fibrous Graft

The long-term reliability of small-diameter vascular grafts (SDVGs) is still largely confined by acute thrombosis, intimal hyperplasia and delayed endothelialization. In this study, a fibrous SDVG containing both physical and biochemical cues was developed to promote rapid endothelialization. The success of our method depends on the integration of a bi-oriented luminal surface with the conjugation of salvianolic acid B (Sal B) via aminolysis and subsequent amidation reaction. Specifically, longitudinally aligned poly (lactide acid-co-ε-caprolactone) (PLCL) microfibers having nano-grooved surface texture provided bi-oriented topographical cues to guide the elongation and migration of endothelial cells (ECs), whilst the incorporation of Sal B served as a biochemical signal to inhibit thrombosis, enhance EC growth and increase von Willebrand factor (vWF) expression in ECs. When implanted into a rat abdominal aorta defect model, the graft was able to facilitate luminal EC coverage, smooth muscle cells infiltration and collagen deposition without causing stenosis or thrombosis. The combination of bi-oriented topography with surface functionalization may become a platform design to maintain patency and accelerate in situ tissue regeneration of SDVG.