| Polyester(ployethylene terephthalate)material is one of the most commonly used biomedical materials.The excellent mechanical properties,acid and alkali resistance,corrosion resistance,and its biocompatibility are better than other synthetic fibers,therefore the polyester is widely used in artificial blood vessels,artificial ligament and other medical materials.However,polyester fiber is a kind of chemically inert polymer which will easily cause intimal hyperplasia if without modification.Therefore,overcoming the natural inertness of the polyester fiber and improving the biocompatibility of biomedical devices are urgent problem in the field of biomedical research.In this study,a coating process was proposed to improve the biocompatibility of polyester fabrics.First,the polyester fabric was treated with alkali reduction treatment,and then two substances,polyurethane and gelatin,were sequentially coated on the surface of the polyester.The effects of alkali treatment and coating process on the physicochemical properties and biocompatibility of polyester fabrics were investigated.The characteristic groups and elemental compositions of the materials were characterized by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy(XPS)and other testing methods,and the coating conditions of polyurethane and gelatin on polyester fabrics were explored.The surface growth morphology of human umbilical vein endothelial cells on the modified fabric was observed,and cell proliferation was evaluated.The hemolysis rate,platelet adhesion degree,recalcification time and other test methods were used to characterize the improvement of the blood compatibility of polyester fabrics by the two coating substances.The results show that alkali treatment can effectively increase the carboxyl group content of polyester fabrics,therefore enhancing the binding ability between polyester fabrics and coating substances.The optimal process of alkali treatment in this experiment is to use dodecyldimethylbenzyl ammonium chloride(1227)as alkali weight loss accelerator,which the concentration is 0.09 g/L.The alkali treatment temperature is 80 ℃,and the alkali concentration is 5 g/L.The weight reduction rate of polyester fabric in aboved method is1.36±0.22%,the content of carboxyl group increased from 18.3 mol/t to 50.7 mol/t,and the tensile strength of polyester fabric decreased from 90.4 MPa to 78.6 MPa.The two groups of samples with and without alkali treatment both were coated.The results showed that the gelatin coating changed the hydrophilicity of the material,and the contact angle decreased from 113° to 82°,which improves adhesion of tissue proteins to polyester fabric surfaces.No significant difference was shown in two groups.The hemolysis rate of the coated materials was lower than 2%.The platelet adhesion experiment showed that the synergistic effect of the polyurethane and gelatin composite coating effectively reduced the platelet adhesion.Recalcification time and APTT test on the surface of the material show that the coated fabrics have good anticoagulation properties.Human umbilical vein endothelial cells are more adhered on the polyester fabric coated with gelatin than other samples,and the spreading degree of the cells on the surface of the polyester material increases significantly after culturing for five days.This study demonstrates that the gelatin and polyurethane composite coating can effectively improve the hemocompatibility and cytocompatibility of the material.This is of great significance to improve the clinical application of artificial blood vessel materials and other medical materials made of polyester fiber. |
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