PTFE Stent Membrane\nBased on the Electrospinning Technique\nand Its Potential for Replacing ePTFE

Expanded poly(tetrafluoroethylene) (ePTFE), obtained\nby the paste\nextrusion-stretching method, is a commonly used stent membrane material\nfor the treatment of arterial stenosis or aneurysm in clinical practice.\nHowever, the structure of ePTFE is nonfibrous, which is not friendly\nto cells, and the equipment consumes a lot of energy and often requires\nthe use of flammable and toxic lubricants. In this study, electrospinning\nwas used to prepare PTFE vascular stent membranes, following plasma\ntreatment, dopamine, and heparin grafting to obtain an anticoagulant\nsurface. The morphology, structure, axial and circumferential tensile\nstrength, porosity, water penetration pressure, and heparin-releasing\nbehaviors of the samples were studied at first. Then, the experiments\nof blood compatibility, cytotoxicity, and <i>in vivo</i> subcutaneous implantation were conducted. Results showed that the\nPTFE electrospun tubular membrane has submicrometer to nanoscale fiber\nstructures similar to the extracellular matrix. The axial and circumferential\ntensile strengths can reach 8.12 and 6.10 MPa, respectively, and the\naxial and circumferential elongations at break can reach 328.75% and\n285.28%, respectively. It maintains higher porosity and water penetration\npressure as well as a longer heparin-releasing period. It has a suitable\nhemolysis rate and superior anticoagulant properties. Dopamine and\nheparin modifications can facilitate the adhesion and proliferation\nof endothelial cells. Histological analysis of the PTFE electrospun\ntubular membrane showed no difference from the commercially available\nePTFE graft.