Synthesis And Biocompatibility Of Surface Modified Polyurethane With Different Charge Types Hydrophilic Structure

Polyurethane materials were widely used in the biomedical field, played an important role in artificial blood vessels and vary equipments of diagnosis and treatment. However, when the polyurethane material in contact with biological tissue, some side-reactions will occur, what limits its direct application in the biomedical aspects. Improve the blood compatibility of the polyurethane material is an essential research task for biomaterial research and development. The modified polyurethane biomaterials are the solution to the blood compatibility of an important method. In this research work, three types of hydrophilic monomers of different charge type were grafted to the surface of Polyurethane films by chemical method, in order to improve the anti-thrombogenicity.We chemically induced graft polymerization of Sodium-vinylbenzene sulfonate(SS)、Sodium-methacrylate(MA)、2-(Methacryloyloxy)ethyltrimethyl ammonium chloride(DMC)、Diallyldimethyl ammonium chloride(DMDAAC)、Sulfa betaine (DMAPS) and Dual ion onto the surface of polyurethane films.The effects of grafting temperature, grafting time, concentrations of monomer and initiator on the grafting rates were studied in detail, determining an optimal reaction conditions. Then series characterization of the modified polyurethane have done to characterize the structure of the grafted polyurethane, such as Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetry (TG) and surface water contact angle measurement have done respectively. The results show that:the three different charge-type hydrophilic monomers were successfully grafted on the surface of the polyurethane film and the hydrophilic of modified polyurethane film have a significant improvement.Moreover, the blood compatibility of the materials of the ungrafted PU films and PU-g-PSS, PU-g-PMA,PU-g-PDMC,PU-g-PDMDAAC,PU-g-PDMAPS and PU-g-Dual ion films were evaluated by hemolysis test, protein adsorption experiments, and platelet adhesion test. The hemolysis rate of PU-g-PSS, PU-g-PMA, PU-g-PDMC, PU-g-PDMDAAC, PU-g-PDMAPS and PU-g-Dual ion films accorded with international standard, the amount of the adsorbed protein has significantly reduced and there were little platelet adhered on the grafted PU films. The results indicated that PU-g-PSS, PU-g-PMA, PU-g-PDMDAAC, PU-g-PDMC, PU-g-PDMAPS and PU-g-Dual ion films could be expected to find wide application in the medical treatment in future.Finally, the anti-clotting mechanisms of three different charge type hydrophilic monomer modified polyurethane film were studied. By means of the Ubbelodhe viscosimeter and circular dichroism, the interaction between Polyurethane materials and bovine serum albumin (BSA) solutions was investigated. The results indicated that PU-g-PMA films can keep the natural molecule conformation of BSA in the course of contacts. The experiments have provided evidence to the hypothesis of "Maintaining Natural Behavior".