Biomimetic Modification Of PTFE Surface And Its Biocompatibility Study

Endothelialization on the surface of artificial blood vessele materials is a promosingapproach to inhibit the subsequent thrombus generation and smooth muscle cell hyperplasia.Recently studies have showed that, the appropriate functioned modification on surface wassupposed to promote endothelial cells adhension and retention.This work aimed to construct an ECM-like bio-functioned layer on PTFE(Polytetrafluoroethylene) surface for endothelial cells attachment and proliferation. Firstly,low temperature plasma was used to activate the PTFE and a bio-functioned layer modifiedwith collagen and heparin was formed via covalent bond sequentially. Contact angle assaryimplied that the hydrophilicity of the surface had been improved, also XPS experiments haveconfirmed the existence of0.4%S elements. The surface functionalized PTFE showed goodblood compatibility, as indicated by extended APTT, no hemolysis and anti-platelet adhesionactivity. Collagen modification equally improved the adhension behavior of both endothelialcells (HUVECs) and smooth muscle cells (HASMCs), i.e., the numbers of cells attached tothe surface increased5times, which showed no selectivity. However, heparin modificationendowed selectivity of the surface for cell adhension, i.e., the amount of endothelial celladhesion was further increased by40%, while the amount of smooth muscle cell adhesionwas reduced65%, given an adhesion ratio of2.5:1.Collagen and heparin were immobilized on the dopamine-modified PTFE surface bySchiff base and Michael addition reaction. Indeed, the amounts of collagen and heparinimmobilized on PTFE surface were significantly increased as indicated by XPSmeasurements. As a result, the hydrophilicity as well as blood comtability was greatlyimproved. Interestingly, cell adhension and cell selecticity properties were improved as well.The number of HUVECs on collagen and heparin modified surface was10times than onPTFE. The HASMCs selectivity of the surface was improved to4:1, indicated heparin playedan important role in regulating surface-cell communication.In comparison, low temperature plasma method was mild, however, it was instable andwith low efficiency due to RF fatigue. The dopamine modify method was convenient andcould immobilize more collagen and heparin. This functionalized surface showed moreevident regulation effect of cell adhesion behavior. Our study provided a clue for artificialvascular endothelialization and anti-smooth muscle cell proliferation.