Phosphorylcholine coating enhances biocompatibility of expanded polytetrafluoroethylene used in polymeric prosthetic heart valves / 中国组织工程研究

ABSTRACT

BACKGROUND:Our preliminary study found that the monocusp valves made of ultramicropore expanded polytetrafluoroethylene (ePTFE) revealed no significant thrombus, calcification, or degradation 20 weeks after implanted into the descending aorta and the left pulmonary artery in sheep, which verified the good property of ePTFE. However, the surface of ePTFE in the left pulmonary artery was covered with obvious neointima. OBJECTIVE: To assess the biocompatibility of phosphorylcholine-coated ePTFE. METHODS:ePTFE surface was modified by phosphorylcholine derivative. Then the changes of surface shape, tensile stress at yield and elasticity modulus, water contact angle, and protein absorption capacity of ePTFE after surface modification were observed. (1) Hemolytic test the leaching solution of phosphorylcholine-coated ePTFE, leaching solution of uncoated ePTFE, normal saline, and distiled water were added to the diluted human blood, respectively. (2) Platelet count test the phosphorylcholine-coated ePTFE, uncoated ePTFE, high density polyethylene, and Zymosan A were added to the whole blood samples from healthy volunteers, respectively. (3) Platelet activation test the phosphorylcholine-coated ePTFE, uncoated ePTFE, γ-Globulins, and Zymosan A were added to the whole blood samples from healthy volunteers, respectively. RESULTS AND CONCLUSION: The mean micropore diameter of ePTFE was significantly decreased after phosphorylcholine coating (P significantly strengthened after phosphorylcholine coating (P ePTFE in biomechanical properties and hemolytic test. The platelet count test and platelet activation test demonstrated that phosphorylcholine coating significantly improved anti-thrombus function of ePTFE. So, phosphorylcholine coating can enhance anti-thrombus function, suppress protein adsorption, and improve biocompatibility of ePTFE.