新型嵌段磷脂仿生聚合物的合成及其用于钛表面改性研究

发布时间：2018-04-21 03:01

本文选题：钛材 + 2-甲基丙烯酰氧乙基磷酸胆碱(MPC)　；参考：《西南交通大学》2015年硕士论文

【摘要】：钛及其合金具有机械强度高、耐腐蚀、生物相容性好等特点,已经广泛的应用于生物医用材料领域。但钛材作为制备植入器械和人工器官的生物医用金属材料,其抗凝血性能还有待进一步提高。2-甲基丙烯酰氧乙基磷酸胆碱(MPC)是一种两亲性的类磷脂分子,它由磷酸胆碱极性头和甲基丙烯酸酯部分组成。其中磷酸胆碱基团(PC基团)是生物细胞外层膜的主要成分,PC基团同时带有正、负两种电荷,具有超强的亲水性,有效阻止了蛋白质的吸附,表现出良好的生物相容性；而乙烯基的存在,可以使MPC聚合成不同类型和功能的类磷脂聚合物,类磷脂聚合物具有仿生结构,可以满足多种生物医学的功能需求。本论文基于改善钛材的血液相容性的目的,合成了两种由MPC单体和TSMA单体聚合而成的ABA型三嵌段共聚物PMPC-PTSMA-PMP C。该共聚物分两步合成,第一步利用MPC单体和链转移剂合成含链转移剂的MPC的均聚物PMPC,第二步是将单体TSMA与第一步合成的聚合物再次进行聚合,合成最终目标ABA型三嵌段聚合物PMPC-PTSMA-PMPC。利用红外光谱(FTIR)、核磁共振(H1NMR)、凝胶渗透色谱(GPC)等表征手段表征了聚合物的结构及分子量。聚合物的检测结果表明,第一步反应中,通过控制链转移剂和引发剂的比例,成功合成了三种PMPC聚合物,三种聚合物的分子量均超过了100KD,分别为192KD、188KD、147KD,并优选出了其中聚合度较好的一种,进行下一步聚合。第二步反应中,通过调控加入的第一步合成的大分子链转移剂的量和TSMA单体的量,成功合成了两种不同分子量的共聚物PMPC-PTSMA-PMPC,分子量分别为134KD和159KD。然后,通过共价接枝的方法将合成的三嵌段共聚物固定到活化之后的钛表面。在此期间,尝试使用质子(CH3OH)和非质子(DMF)两种溶剂将聚合物固定,以期优选出接枝量较大、较为均一的表面改性层。红外光谱(FTIR)、水接触角(WCA)和X射线光电子能谱(XPS)等表征分析结果证明,多功能层组装成功；通过扫描电子显微镜(SEM)观察改性层的形貌,结果显示经过CH30H溶剂固定的涂层聚合物含量较多,而DMF做溶剂时固定的聚合物量很少。初步的血液相容性试验表明,改性后的表面能抑制血小板粘附和激活,对纤维蛋白原的粘附和激活也有一定的抑制作用。所以,在钛表面构建磷酸胆碱聚合物仿生改性涂层可以有效的改善钛材的血液相容性。
[Abstract]:Titanium and its alloys have been widely used in biomedical materials due to their high mechanical strength, corrosion resistance and biocompatibility. However, the anticoagulant properties of titanium, as biomedical metal materials for the preparation of implants and artificial organs, need to be further improved. MPCs are amphiphilic phospholipid molecules. It consists of a polar head of choline phosphate and a portion of methacrylate. The PC group of choline phosphate group is the main component of the outer membrane of biological cells. The PC group has both positive and negative charges and has super hydrophilicity, which effectively prevents the adsorption of protein and shows good biocompatibility. The existence of vinyl can make MPC polymerize into phospholipid polymers of different types and functions. Phospholipid polymers have biomimetic structure and can meet the functional needs of many biomedicine. In order to improve the blood compatibility of titanium, two kinds of ABA triblock copolymers, PMPC-PTSMA-PMP C, which were polymerized by MPC monomer and TSMA monomer, were synthesized in this paper. The copolymer was synthesized in two steps. In the first step, the homopolymer PMPCs of MPC containing chain transfer agent were synthesized by using MPC monomer and chain transfer agent. In the second step, the monomer TSMA was polymerized again with the polymer synthesized in the first step, and the final target ABA triblock polymer PMPC-PTSMA-PMPCwas synthesized. The structure and molecular weight of the polymer were characterized by FTIR, NMR and GPC. The results showed that in the first step, three kinds of PMPC polymers were successfully synthesized by controlling the ratio of chain transfer agent and initiator. The molecular weights of the three kinds of polymers were all over 100 KD, respectively, and the one with better degree of polymerization was selected for further polymerization. In the second step, two copolymers, PMPC-PTSMA-PMPCs with different molecular weights, were successfully synthesized by adjusting the amount of macromolecular chain transfer agent and TSMA monomer. The molecular weights of the copolymers were 134KD and 159KD, respectively. The synthesized triblock copolymers were then immobilized onto the activated titanium surface by covalent grafting. During this period, two kinds of solvents, proton CH3OH) and non-protonated DMF, were used to immobilize the polymer in order to select a relatively uniform surface modification layer with large grafting amount. The results of FTIR, water contact angle (WCA) and X-ray photoelectron spectroscopy (XPS) show that the multifunctional layer was successfully assembled, and the morphology of the modified layer was observed by scanning electron microscope (SEM). The results show that the amount of polymer fixed by CH30H solvent is more than that by DMF solvent. Preliminary blood compatibility test showed that the modified surface could inhibit platelet adhesion and activation and fibrinogen adhesion and activation. Therefore, the biomimetic coating of choline phosphate polymer on titanium surface can effectively improve the blood compatibility of titanium.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB324

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