Promotion of Endothelial Cell Adhesion and Antithrombogenicity of Polytetrafluoroethylene by Chemical Grafting of Chondroitin Sulfate

Polytetrafluoroethylene (PTFE) is one of the polymers extensively applied in biomedicine. However, the application of PTFE as a small-diameter vascular graft results in thrombosis and intimal hyperplasia because of the immune response. Therefore, improving the biocompatibility and anticoagulant properties of PTFE is a key to solving this problem. In this study, a hydroxyl group-rich surface was obtained by oxidizing a benzoin-reduced PTFE membrane. Then, chondroitin sulfate (CS), an anticoagulant, was grafted on the surface of the hydroxylated PTFE membrane using 3-aminopropyltriethoxysilane. The successful modification of the membrane in each step was demonstrated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Hydroxylation and the grafting of CS greatly increased the hydrophilicity and roughness of membrane samples. Moreover, the hydroxylated PTFE membrane enhanced the adhesion ability of endothelial cells, and the grafting of CS also promoted the proliferation of endothelial cells and decreased platelet adhesion. The results indicate that the PTFE membranes grafted with CS are able to facilitate rapid endothelialization and inhibit thrombus formation, which makes the proposed method outstanding for artificial blood vessel applications.