【作者】 胡梦欣；

【导师】 徐志康；

【作者基本信息】 浙江大学 ， 高分子化学与物理， 2009， 博士

【摘要】 生物膜表面的“糖被”赋予了生物膜良好的亲水性和生物特异性，不但具有抵御外来物质非特异性黏附的性能，还具备选择性识别和吸附目标物质的功能，广泛参与了细胞分化、发育、免疫、老化、癌变等生命和疾病过程。“糖被”致密的糖基化层结构显著增强了它与目标分子间的亲和力，满足了各项生理活动的需求。在高分子分离膜表面构建类似于“糖被”的糖基化层，可实现对生物膜表面的仿生模拟，拓展分离膜的应用范围和领域。本论文建立了一种通用的糖基化方法，在聚丙烯微孔膜表面构建高密度糖基化层，以期实现对生物膜表面“糖被”的模拟，获得具有糖生物功能的聚丙烯微孔膜。具体研究工作主要围绕以下几个方面展开：1、以FeCl₃为必需光引发剂，结合传统光引发剂二苯甲酮（BP），采用紫外光辐照接枝法，成功引发了甲基丙烯酸羟乙酯（HEMA）在聚丙烯微孔膜上接枝聚合。FeCl₃和BP之间的“协同效应”大大提高了接枝密度。HEMA接枝改性膜具有良好的亲水性和血小板相容性，抗蛋白质污染的能力得到提高。2、建立一种糖基化方法，将乙酰化的单糖（葡萄糖和半乳糖）和二糖（麦芽糖和乳糖）引入HEMA接枝改性膜，得到四种不同的糖基化聚丙烯微孔膜。HEMA的高接枝密度和催化剂BF₃·Et₂O的高效性，大幅度提高了糖基密度。固定有大量糖基的HEMA接枝链较好地模拟了生物膜表面的聚糖结构，使糖基化聚丙烯微孔膜具有良好的仿生功能，显示了强烈的“糖苷集簇效应”。3、以葡萄糖糖基化聚丙烯微孔膜为亲和膜，选择性吸附分离Con A。发现亲和膜选择性吸附Con A的能力非常强，形成了多层吸附，其结合容量随糖基密度的增加而提高。葡萄糖和甲基-α-D-吡喃甘露糖苷溶液作为洗脱液时洗脱效果不理想，而1 M的HAc溶液则能洗脱90％-100％吸附的Con A。4、比较了大鼠肝细胞在糖基化聚丙烯微孔膜表面的培养情况。发现肝细胞在半乳糖和乳糖糖基化膜表面黏附数量与胶原涂敷膜表面相当。肝细胞在胶原涂敷表面呈扁平铺展状，与材料表面作用强烈，细胞间作用很弱；而在半乳糖和乳糖糖基化膜表面呈圆球形且形成了多细胞聚集体，与材料表面作用较弱，细胞之间作用强烈。更多还原

【Abstract】 The glycocalyx on the external cell membranes endows the cell membrane surfacewith well hydrophilicity and biocompatibility, which not only prevents undesirablenon-specific adhesion of foreign substance, but also possesses specific recognitionproperties for target molecules. It widely participates in biological processes, such ascellular differentiation, development, immune response, senescence, carcinogenesis. Thedense structure of carbohydrate layer in glycocalyx enhances the affinity betweencarbohydrates and their target molecules, which meets the demand of differentphysiological activities. To construct glycosylated layer on the surface of polymericmembrane is expected to biomimic the glycocalyx and expand the application fields ofmembranes.In this thesis, a versatile method was constructed to prepare high-density glycosylatedmicroporous polypropylene membranes （MPPMs） with glycobiological functions to mimicthe the glycocalyx of cell membranes. Our detailed works are mainly concentrated on thefollowing aspects:1. Using FeCl₃ and BP as photoinitiators, 2-hydroxyethyl methacrylate （HEMA） wassuccessfully grafted on MPPMs by UV-induced grafting polymerization. The synergisticeffect between FeCl₃ and BP greatly enhanced the grafting density （GD）. Thepoly（HEMA）-grafted MPPMs showed well protein resistance and potentialhemocompatibility due to the enhancement of hydrophilicity.2. Using poly（HEMA）-grafted MPPMs as supports, high density glycosylation ofmembranes was achieved by a versatile method with mono- and di-saccharides. The highGD of HEMA and high catalytic activity of BF₃·Et₂O greatly increased the binding degree（BD） of saccharide moieties. The poly（HEMA） chains hanging with a great number ofsaccharide moieties mimic the structure of glycan on the cell membrane, which showstrong "glycoside cluster effect" and endow the glycosylated MPPMs with goodglycobiological functions.3. The glucosylated MPPMs were used as affinity membranes for Con A separation onthe basis of the specific interactions between saccharide ligands and lectins. The bindingcapacity of glucosylated MPPMs increased by multilayer adsorption of Con A andincreased with BD of glucose. Compared with the competitive eluants, such as glucose andmethylα-mannopyranoside, 1 M Hac solution is more effective to elute the adsorbed Con A from the affinity membranes.4. The glycosylated MPPMs were taken as the substrates to culture hepatocytes invitro. The number of hepatocytes adhered on the poly（HEMA）-grafted and glucosylatedMPPMs was less, while that on the galactosylated and lactosylated MPPMs werecomparable with the collagen coating membranes. Hepatocytes became spreading on thecollagen coating MPPM, and had strong interaction with substrate. However, hepatocyteson the galactosylated and lactosylated MPPMs maintained spherical shapes and formedspheroid with multiple cells, showing weak interaction with substrate and stronginteraction between cell-cell.更多还原