Long-term nitric oxide release for rapid endothelialization in expanded polytetrafluoroethylene small-diameter artificial blood vessel grafts

Abstract

Without a complete and confluent endothelial layer covering the luminal surface, expanded polytetrafluoroethylene (ePTFE) small-diameter (<6 mm) artificial blood vessels would fail in vivo due to thrombosis and restenosis. In order to promote rapid endothelialization and anticoagulation, we modified the surface of ePTFE by effectively grafting functional biomolecules, such as nitric oxide (NO) catalyst selenocystamine (SeCA) and vascular endothelial growth factor (VEGF), via dopamine coating. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results showed the successful incorporation of SeCA and VEGF. The release profile of NO, a cell-signaling molecule that regulates cell behavior and platelet aggregation, lasted beyond 35 days and could be controlled by the ratio of SeCA to dopamine. The biological results in terms of cell culture and antithrombogenic properties showed that the surface functionalization strategies promoted human coronary artery endothelial cell (HCAEC) growth and proliferation while preventing platelet adhesion and the formation of thrombi in vitro. A complete endothelial cell monolayer on ePTFE was found to form by day 10. This simple and effective surface functionalization method is beneficial for the eventual clinical application of small-diameter ePTFE blood vessel grafts.