PTFE Stent Membrane Based on the Electrospinning Technique and Its Potential for Replacing ePTFE

Expanded poly(tetrafluoroethylene) (ePTFE), obtained by the paste extrusion-stretching method, is a commonly used stent membrane material for the treatment of arterial stenosis or aneurysm in clinical practice. However, the structure of ePTFE is nonfibrous, which is not friendly to cells, and the equipment consumes a lot of energy and often requires the use of flammable and toxic lubricants. In this study, electrospinning was used to prepare PTFE vascular stent membranes, following plasma treatment, dopamine, and heparin grafting to obtain an anticoagulant surface. The morphology, structure, axial and circumferential tensile strength, porosity, water penetration pressure, and heparin-releasing behaviors of the samples were studied at first. Then, the experiments of blood compatibility, cytotoxicity, and in vivo subcutaneous implantation were conducted. Results showed that the PTFE electrospun tubular membrane has submicrometer to nanoscale fiber structures similar to the extracellular matrix. The axial and circumferential tensile strengths can reach 8.12 and 6.10 MPa, respectively, and the axial and circumferential elongations at break can reach 328.75% and 285.28%, respectively. It maintains higher porosity and water penetration pressure as well as a longer heparin-releasing period. It has a suitable hemolysis rate and superior anticoagulant properties. Dopamine and heparin modifications can facilitate the adhesion and proliferation of endothelial cells. Histological analysis of the PTFE electrospun tubular membrane showed no difference from the commercially available ePTFE graft.