【作者】 刘娜；

【导师】 陈晓农；

【作者基本信息】 北京化工大学 ， 高分子化学与物理， 2009， 硕士

【摘要】 在生物医用方面,材料生物相容性的研究一直是科研工作者关心的问题。生物相容性主要包括组织相容性和血液相容性。合成材料与血液接触后易导致凝血,这是由于血液蛋白的吸附,继而是血小板和其它血液有形成分的粘附,导致凝血酶生成,最后形成血栓。组织相容性表现为组织排异,感染等系列问题。大量研究表明,蛋白在材料表面的吸附是血栓形成,细胞吸附和细菌导致感染等一系列问题的诱因。因此,抑制非特异性蛋白吸附是改善材料表面生物相容性的有效途径。通过对材料或制品表面进行改性,在材料表面形成亲水阻隔层,使蛋白不与材料直接接触,进而改善生物相容性。在材料表面预吸附水溶性聚合物是改善材料生物相容性的方法之一。本研究以预吸附两亲性聚合物改善材料表面抗蛋白吸附性能,进而提高材料生物相容性为目的。首先制备了不同组成与结构的PNIPAM(聚异丙基丙烯酰胺)-b-PVP(聚乙烯基吡咯烷酮)梳状嵌段共聚物,用~1H-NMR、GPC、等方法对其进行了表征。用光散射、浊度测定、高速离心-液相浓度测定等方法研究了所制备的共聚物在单分散PS微球表面的预吸附和抗蛋白吸附行为;用接触角和X射线光电子能谱(XPS)测试的方法研究了共聚物在PS片状材料表面的预吸附行为及吸附稳定性。主要内容如下:1、VP的RAFT聚合验证,使用紫外吸光度法测定不同反应时间下溶液吸光度,得到转化率随反应时间基本成线性关系。2、用RAFT(可逆-加成-断裂-链转移)可控自由基聚合法结合大分子单体技术制备出具有不同支链长度和密度的PNIPAM-b-PVP梳状嵌段共聚物。3、考察所制备共聚物在PS片材表面的预吸附及吸附稳定性,研究结果表明共聚物预吸附到PS片材表面后,PS片材表面接触角均有所下降,且预吸附的片材在蒸馏水中,25℃和37℃下以30rpm频率振荡30天后不发生明显脱吸附。4、比较了不同结构和组成梳状嵌段共聚物的抗蛋白吸附效果。研究发现亲水链段和支链长度增加有利于抗蛋白吸附;但是亲水段含量过大时,疏水段含量相对较少,使其不能提供对材料表面足够的附着力,反而不利于抗蛋白吸附。更多还原

【Abstract】 In the field of biomedical aspects, the study of material biocompatibility has been a hotspot in scientific research. Biocompatibility mainly includes histocompatibility and hemocompatibility. Synthetic materials in contact with the blood may lead to blood coagulation, which is due to protein adsorption, followed by blood platelets and other formed elements adhesion, leading to thrombin produced, and finally the formation of thrombosis. A large number of studies show that protein adsorption is the inducement of thrombosis, cell adsorption and bacterial infection and a series of problems. Therefore, the inhibition of non- specific protein adsorption is an effective way to improve the biocom- patibility. Pre-adsorption water-soluble polymer on the surface of materials is one of the methods to improve the biocompatibility.The purpose of this study is pre-adsorption of amphiphilic polymers on the surface to resist protein adsorption and thus improve the biocompatibility. Several PNIPAM-PVP comb block copolymers were synthesized by RAFT. ~1H-NMR and GPC were used to characterize those new kinds of amphiphilic copolymers. Their properties of pre-adsorption and protein adsorption resistance on monodisperse PS microsphere were investigated by dynamic light scattering, UV quantitative analysis and turbidity determination. Contact angle and X-ray photoelectron spectroscopy (XPS) were used to measure the pre-adsorption and adsorption stability of the copolymer on PS sheet samples. The main contents are as followed:1、The verification of RAFT polymerization is investigated. UVabsorbance determination was used to measure the relationship betweenmonomer conversion and reaction time which showed a linearrelationship in this study.2、PNIPAM-PVP with different graft length and density weresynthesized by using RAFT controllable free radical polymerizationtechnique and PVP macromonomer technology.3、The results of pre-adsorption and adsorption stability ofcopolymer on PS sheet samples showed contact angle decreased afterpre-adsorption and no remarkable desorption was observed by 30rpmfrequency shaking 30 days at 25℃or 37℃.4、More content of hydrophilic branches in the copolymer resultedin a better protein resistance. However, it is not conducive to the effect ofprotein adsorption resistance with excessive hydrophilic segment and less hydrophobic segment so that it can not provide enough adhesion to the surface.更多还原