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首页> 外文学位 >Surface modification through atom transfer radical polymerization grafting for the preparation of protein-resistant materials.
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Surface modification through atom transfer radical polymerization grafting for the preparation of protein-resistant materials.

机译：通过原子转移自由基聚合接枝进行表面改性，以制备抗蛋白质材料。

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摘要

Surface-initiated atom transfer radical polymerization (ATRP) is a recently developed controlled/living radical polymerization technique for surface grafting of end-tethered polymer chains with controlled pattern, chain length, density, and functionality. These parameters are important in understanding the molecular mechanism of resistance to protein adsorption and cell adhesion to polymer grafted surfaces. The main focus of this thesis is the synthesis of phosphory1choline (PC)- and poly(ethylene oxide) (PEO)-based model surfaces with varying graft densities and chain lengths via surface-initiated ATRP, and the effects of graft density and chain length on their non-biofouling behaviours, including protein adsorption and platelet adhesion.; 2-Methacryloyloxyethyl phosphorylcholine (MPC, MW 295 g/mol) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA, MW 300 g/mol, PEO side chains of average length n = 4.5) were chosen as model monomers containing PC and PEO side chains of comparable length and were grafted on silicon wafer surfaces. The graft density and chain length of poly(MPC) and poly(OEGMA) were controlled via the surface density of the ATRP initiator and the ratio of monomer to sacrificial initiator. The graft density was systematically varied from 0.06 to 0.39 chains/nm2, and the chain length from 5 to 200 monomer units for both poly(MPC)- and poly(OEGMA)-grafted silicon wafer surfaces. The compositions of the grafted surfaces were confirmed by x-ray photoelectron spectroscopy (XPS).; Fibrinogen and lysozyme, two proteins of significantly different size, were used as models to study protein interactions with the grafted surfaces. Adsorption was measured using radiolabelling methods in single protein solutions and binary mixtures in TBS buffer. It was found that adsorption to both poly(MPC) and poly(OEGMA) surfaces decreased with increasing graft density and chain length, and that graft density is more important than chain length in determining protein resistance.; The effect of polymer type, i.e., poly(MPC) versus poly(OEGMA), on protein adsorption was also of great interest since PC and PEO are among the most effective motifs used for modifying surfaces to prevent protein adsorption. It was found, somewhat surprisingly, that for a given chain length and density, adsorption from TBS buffer on both polymer surface types was basically the same.; To investigate further the effect of polymer type on protein adsorption, we determined the water content and thickness of poly(MPC) and poly(OEGMA) layers in D2O using neutron reflectometry. It was found that both poly(MPC) and poly(OEGMA) grafted chains were highly stretched, and that the water fractions in poly(MPC) and poly(OEGMA) layers having similar graft density were comparable. We concluded that the water content of poly(MPC) and poly(OEGMA) layers is strongly correlated to their protein resistance.; The interactions of these surfaces with proteins and platelets in plasma and whole blood were also investigated. These media are more relevant to the application of the surfaces as blood-contacting biomaterials. It was found that both poly(MPC) and poly(OEGMA) surfaces of high graft density (0.39 chains/nm 2) adsorbed identical and extremely low levels of proteins and platelets; however, at low graft density (0.10 chains/nm2), poly(OEGMA) was more effective than poly(MPC) in resisting protein adsorption and platelet adhesion.
机译：表面引发的原子转移自由基聚合（ATRP）是最近开发的受控/活性自由基聚合技术，用于对末端束缚的聚合物链进行表面接枝，并控制图案，链长，密度和官能度。这些参数对于理解抗蛋白质吸附和细胞粘附至聚合物接枝表面的分子机制很重要。本文的主要重点是通过表面引发的ATRP合成具有不同接枝密度和链长的磷酸胆碱（PC）和聚环氧乙烷（PEO）基模型表面，以及接枝密度和链长的影响其非生物污染行为，包括蛋白质吸附和血小板粘附。选择2-甲基丙烯酰氧基乙基磷酰胆碱（MPC，MW 295 g / mol）和低聚（乙二醇）甲基丙烯酸甲酯甲基醚（OEGMA，MW 300 g / mol，PEO侧链平均长度n = 4.5）作为包含PC和PEO的模型单体相当长度的侧链，并被嫁接到硅晶片表面。聚（MPC）和聚（OEGMA）的接枝密度和链长是通过ATRP引发剂的表面密度和单体与牺牲引发剂的比例来控制的。对于聚（MPC）-和聚（OEGMA）-接枝的硅晶片表面，接枝密度系统地从0.06-0.39链/ nm2变化，链长从5-200个单体单元变化。接枝表面的组成通过X射线光电子能谱法（XPS）确认。纤维蛋白原和溶菌酶这两种大小截然不同的蛋白质被用作研究蛋白质与移植表面相互作用的模型。使用放射性标记方法在单一蛋白质溶液和TBS缓冲液中的二元混合物中测量吸附。结果发现，随着移植物密度和链长的增加，对聚（MPC）和聚（OEGMA）表面的吸附均降低，并且在确定蛋白抗性时，移植物密度比链长更重要。聚合物类型，即聚（MPC）与聚（OEGMA）对蛋白质吸附的影响也引起了极大的关注，因为PC和PEO是用于修饰表面以防止蛋白质吸附的最有效基序之一。令人惊讶地发现，对于给定的链长和密度，两种聚合物表面类型上来自TBS缓冲液的吸附基本相同。为了进一步研究聚合物类型对蛋白质吸附的影响，我们使用中子反射测定法确定了D2O中的poly（MPC）和poly（OEGMA）层的水含量和厚度。发现聚（MPC）和聚（OEGMA）接枝链均被高度拉伸，并且具有相似接枝密度的聚（MPC）和聚（OEGMA）层中的水分数是可比的。我们得出的结论是，聚（MPC）和聚（OEGMA）层的水分含量与其蛋白抗性密切相关。还研究了这些表面与血浆和全血中蛋白质和血小板的相互作用。这些介质与表面作为接触血液的生物材料的应用更为相关。结果发现，移植物密度高（0.39链/ nm 2）的聚（MPC）和聚（OEGMA）表面均吸附相同且极低水平的蛋白质和血小板。然而，在低移植物密度（0.10链/ nm2）下，poly（OEGMA）在抵抗蛋白质吸附和血小板粘附方面比poly（MPC）更有效。

著录项

  • 作者

    Feng, Wei.;

  • 作者单位

    McMaster University (Canada).;

  • 授予单位 McMaster University (Canada).;
  • 学科 Engineering Chemical.
  • 学位 Ph.D.
  • 年度 2007
  • 页码 267 p.
  • 总页数 267
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化工过程（物理过程及物理化学过程）;
  • 关键词

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