【作者】 梁博；

【导师】 万昌秀；

【作者基本信息】 四川大学 ， 生物医学工程， 2005， 硕士

【摘要】 聚砜（Polysulfone,PSF）作为血浆分离（Plasmapheresis）的膜材料具有十分优良的生物相容性、化学稳定性和机械强度等性能,与其他合成材料相比已广泛受到临床医学界的欢迎。但是聚砜的疏水性使其在血浆分离过程中出现严重的膜污染问题——主要是蛋白质在聚砜膜上的不可逆吸附,可以使超滤膜的通过率下降30%以上,一旦蛋白质的构象发生变化还会诱发血液凝固和免疫系统活化等一系列有害结果。目前国内外防止蛋白质污染研究得最多的方法是利用物理或化学方法对膜表面进行亲水性改性。通过对表面的改性既可以保持材料本体结构固有的机械强度,又能使其具有必需的表面性能,达到功能性和生物相容性的统一。其中在材料表面周定聚乙二醇（Poly（ethylene glycol）,PEG）的研究己广泛丌展,已有许多文献和专利发表。在90年代有人发现单层聚乙二醇刷抗蛋白质污染的能力远比一般多层涂层效果好。本论文以溶剂旋涂法所制成的聚砜薄膜作为改性材料,采用紫外辐照法,以对叠氮苯甲酸（4-Azidobenzoic acid,AzBA）为光活性分子,将PEG聚合物接枝到聚砜薄膜表面,为下一步在聚砜超滤膜上接枝PEG分子层打下基础。 本论文以萘钾为催化剂,用聚乙二醇单甲醚（Methoxy poly（ethylene glycol）,MPEG）和对甲苯磺酰氯在N₂保护下,合成了对甲苯磺酰基聚乙二醇（MPEG-OT_s）。再根据经典的Gabriel法,在邻苯二甲酰亚氨钾盐和水合肼的作用下,将MPEG-OT_s转化为MPEG-NH₂,最后产物用二氯甲烷/乙醚混合液重结晶三次,得到了高纯度结晶的MPEG-NH₂,同时通过核磁共振和高效液更多还原

【Abstract】 As a membrane material used in plasmapheresis, polysulfone (PSF) has advantages in aspects of biocompatibility, chemo stability, mechanical strength, which make it popular in the field of biomedical materials. But the hydrophobic of PSF would cause serious fouling during the process of plasmapheresis, resulting in the irreversible adsorption of proteins on membranes, and reducing their permeability at least 30%. Once the conformation of the absorbed proteins changed, severe injuries would take place, such as blood coagulation and activation of immunosystem. In order to prevent the fouling of proteins, most efforts of current researches are focused on hydrophilic modification of membrane surfaces. Through the hydrophilic modification, researchers expect to obtain biocompatible surfaces and maintain the intrinsic bulk properties of the material. Among these researches, physisorption and covalent attachment of poly(ethylene glycol) on surface of various materials has long been studied widely and there’re a lot of papers and patents being published in the past three decades. In 1990’s, it was found that the capability of mono-layered PEG brush to resist protein fouling was much greater than that of multi-layered PEG. In this paper, spin coated PSF films were used as the material to be surface-modified by grafting brush-like PEG with 4-azidobenzoic acid photocoupler. Achievement of UV irradiation grafting of MPEG on polysulfone films may provide the foundation for further advancement in tethering brush-like PEG on ultrafiltration Psf membrane.By using potassium naphthalene as catalyst, MPEG-OTs was synthesized from MPEG and 4- tolylsulfonyl chloride. According to Gabriel’s method, MPEG-NH2was synthesized from MPEG-OTs and potassium phthalimide, and purified by means of recrystallization in dichloromethane//ether mixture at least three times until crystal pure product obtained. And analyses of Aldrich’s MPEGs used in this study show that these polymers contain only undetectable amounts of bifunctional PEG.On the other hand, the glass coverslips are spin-coated with a 3%(w:w) solution of polysulfone in 1,2-dichlorobenzene( 1 Os at 1000 rpm and consecutively for 50s at 3000 rpm). Then we measured the relative spectral energy distribution of self-designed 365nm UV-radiation apparatus, the radiation intensity distribution with light filter and temperature.4-azidobenzoic acid (AzBA) which was prepared by the addition of sodium azide to the acidic diazonium chloride from 4-aminobenzoic acid was purified in ethanol water solution (ethanol: H2O= 6(v): 4(v)), and got crystal pure. Furthermore, AzBA was grafted to the polysulfone films under the following conditions: in the darkroom, adjust the concentration of AzBA to 25.8g/l, with the amount was lml; keep Psf films wet during UV irradiation for lOmin. By the results of XPS and AFM analysis, AzBA has been grafted on polysulfone successfully. Then used l,3-(3-dimethylaminopropyl)ethylcarbodiimide(EDC) as photocoupler, MPEG-NH2 through its amino group reacted with the -COOH of AzBA forming amide bond and grafted on.From water contact angle and protein absorption measurements, there was a improvement of hydrophilicity of the PSF films grafted with MPEG . Efficiency of reacting of AzBA and MPEG-NH2 by X-ray photoelectron spectroscopy was 72%. With atomic force microscope (AFM), very low roughness of the grafting layer indicates the high density of MPEG . The presence of a PEO-brush was demonstrated using ellipsomtry.更多还原