Research On The Synthesis Of New Block Phospholipid Biomimetic Polymers And Application In Titanium Surface Modification

Titanium and its alloys have high mechanical strength, corrosion resistance, good biocompatibility and other features, has been widely applied in the field of biomedical materials. But titanium and its alloys as the biomedical metallic materials and the preparation of implant devices and artificial organs, its anticoagulant properties to be further improved.2-methacryloyloxyethyl phosphorylcholine (MPC) is an amphiphilic phospholipid molecule, which consists of a phosphorylcholine polar head and methacrylate components. Which phosphorylcholine group (PC) is a major component of the outer membrane of biological cells, PC groups at the same time with both positive and negative charges, with superior hydrophilic performance, effectively prevent the adsorption of proteins, exhibit good biocompatibility; and vinyl presence allows MPC polymerized into different types and functions of phospholipid polymer, phospholipid polymer having bionic structure, so as to meet a variety of biomedical functional requirements.In this paper, based on the purpose of improving the blood compatibility of titanium, two kinds of ABA triblock copolymer PMPC-PTSMA-PMPC were designed and synthesized using the MPC and TSMA monomers. The copolymer synthesized in two steps, the first step in the use of MPC monomer and chain transfer agent, get the homopolymer PMPC which containing the chain transfer agent. The second step is based on the first step, add in the second monomer TSMA, after a period of reaction,so as to get the ultimate goal of synthesizing ABA type triblock polymer PMPC-PTSMA-PMPC.By using the FTIR, H1NMR, GPC-vis characterization methods, the polymers’ structure and molecular weight were identified. Test results show that in the first step reaction, by controlling the ratio of chain transfer agent and initiator, three polymer PMPC successfully synthesized, the molecular weight of the three polymers are more than 100KD, respectively 192KD,188KD,147KD, and choose the best of the three which has a better degree of polymerization,as a raw material of the next step polymeriation. The second-stage reaction, in the regulation of the amount of the monomer TSMA and the amount of macromolecular chain transfer agent which is synthesized by the first step, successfully synthesized two different molecular weight copolymer PMPC-PTSMA-PMPC, theirs molecular weight are 134KD and 159KD.Then, we use covalent grafting method to construct a triblock copolymer coating on the titanium surface after activation. In the meantime, try use protic and aprotic solvents to fixing polymer coating, preferably to get greater grafted amount and get a more uniform modification layer. Infrared spectroscopy (FTIR), water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS) analysis to characterize the polymer coating, the results prove we successfuliy construct a multifunction layer; The modified layer morphology was observed by scanning electron microscopy (SEM), the results show that after two different solvents fixed the surface which topography has no significant difference.The blood test results displayed that the modified surface can inhibit platelet adhesion and degeneration.So, in the building of a phosphorylcholine polymer biomimetic modified coating on titanium surface can effectively improve the blood compatibility of titanium.