Construction And Evaluation Of Phospholipid/Peptide Biomimetic Multifunctional Coating On 316L Biomedical Stainless Steel

316L Stainless Steel performed well in its mechanical properties, corrosion resistance and biocompatibility, which made it a better biomaterial and it has been widely applied in biomedical field. However, the ion releasing from the material surface and the surface thrombosis have caused many issues in biocompatibility after the implanting of cardiovascular devices. The improvement ought to be focused on the blood compatibility of materials and the regulation which between material itself and the surrounding tissue.2-methacryloyloxyethyl phosphorylcholine (MPC) is the main component of phospholipid molecules. The hydrophilic choline phosphate group and the hydrophobic methacrylate group formed to the structure of MPC, meanwhile, the ethenyl from methacrylate group could provide a great platform for MPC to forming different phospholipid polymers with corresponding function, by which a great blood compatibility could be accomplished.To improve the blood compatibility and get the surface endothelialized of 316L stainless steel, several phospholipids biomimetic polymers were designed and synthesized. Three different monomers MPC, Methacrylic Acid (MA) and N-2-(3,4-dihydroxylphenyl)ethyl methacrylamide (DMA) were prepared to synthesize four different phospholipid polymers (PDMMPC5-I, PDMMPC5-II, PDMMPC7-I, PDMMPC7-II). The DMA monomer was synthesized firstly with dopamine and methacrylic anhydride. Secondly, the four phospholipid polymers were obtained by random copolymerization reaction. At the same time, we prepared the POMMPC polymer by oxidizing the PDMMPC7-I. The PC group, carboxyl group and phenolic hydroxyl group were commonly found from the four phospholipid polymers described above. The phenolic hydroxy groups could anchor the polymer stably on the surface of material, PC group would suppress the adhesion of platelet and the laminin could grafting with carboxy group, based on which the POMMPC polymer and the peptide (RK-13) would grafted by self-assembly method. The construction of LBL coating meliorated the biocompatibility of 316L stainless steel.By using FTIR,1H NMR, UV-Vis characterization methods, the monomer DMA and four phospholipid polymers were successful synthesized and detected:DMA was obtained at the yield of 70% and the Molar aggregation ratio of four phospholipid polymers have close value to the Molar feed ratio.The QCM detection is focused on the immobilization amount of four polymers and the results showed that polymer PDMMPC5-I has more immobilized amount because the high ratio of DMA. The stability test proved that four phospholipid polymers were steadily exist on the surface after immersed in PBS buffer for 2 months. Blood experiment to these polymers could be concluded that PDMMPC7-I and PDMMPC5-I have better compatibility abilities to blood. Considering the immobilization amount and blood compatibility, PDMMPC5-I was choosed as the surface modified coating.Above all, the Layer-by-Layer self-assembly method was applied to the construction of Ln/POMMPC/(RK-13) coating on 316L stainless steel. The XPS, WCA and QCM results demonstrated the LBL coating was successful established. After the preliminary test of hemocompatibility and cytocompatibility, the modified surface would reduce the degree of platelet activation and promote the adhesion and proliferation of endothelial cells and endothelial progenitor cell, by which a relatively and ideally bioactive surfaces could be achieved.