Correlation between the structure of water in the vicinity of carboxybetaine polymers and their blood-compatibility
Correlation between the structure of water in the vicinity of carboxybetaine polymers and their blood-compatibility
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DOI：
10.1021/la0515571
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发表时间：
2005-12-06
期刊：
影响因子：
3.9
通讯作者：
Yokoyama, Y
中科院分区：
文献类型：
--
作者：
Kitano, H;Tada, S;Yokoyama, Y
研究了不同相对分子质量的羧基甜菜碱均聚物(聚[1-羧基-N，N-dimethyl-N-(2‘-methacryloyloxyethyl)methanaminium内盐])及其与甲基丙烯酸正丁酯的无规共聚物(聚[1-羧基-N，BMA])在水溶液和薄膜中的结构和氢键，并用拉曼光谱的O-H伸缩和衰减全反射红外光谱进行了表征。聚(CMB-r-BMA)水溶液的拉曼光谱O-H伸缩的长程耦合对应的集体带(C值)的相对强度与纯水非常接近，而普通聚电解质水溶液的C值较小。根据C值可以计算出PolyCMB和Poly(CMB-r-BMA)(CMB，45mol%)(M-w分别为1.14×10(4)和1.78×10(4))中一个单体残基(N-corr值)引起的氢键坍塌数量。N-corr值远小于普通聚电解质，接近于聚乙二醇、聚N-乙烯基吡咯烷酮等非离子水溶性聚合物的N-corr值。此外，具有较大BMA含量(M-w=347 kD，CMB 27摩尔%)的水不溶聚合物(CMB-r-BMA)可以在ZnSe晶体上浇铸成薄膜(厚度约10微米)，用于ATR-IR分析。在聚(CMB-r-BMA)膜吸水初期，膜内水的O-H伸缩谱带与自由水的O-H伸展峰相似，而聚甲基丙烯酸甲酯(PMMA)和聚甲基丙烯酸丁酯(PBMA)膜中水的O-H伸展峰发生了剧烈变化。用密度泛函方法计算了与甜菜碱分子水合的水分子的理论振动频率，与实验结果一致，人血小板与聚(CMB-r-BUA)膜的粘附力远低于PMMA和PBMA。随着CMB残留量的增加，聚(CMB-r-BMA)膜上的血小板数量急剧减少，然后逐渐增加，这可能是由于膜的表面粗糙度增加所致。这些结果表明，具有两性离子结构的羧基甜菜碱单体残基不会显著干扰水分子在水溶液和薄膜体系中的氢键，从而使羧基甜菜碱聚合物具有良好的血液相容性。
The structure and hydrogen bonding of water in the vicinity of carboxybetaine homopolymer (poly[1-carboxy-N,N-dimethyl-N-(2'-methacryloyloxyethyl)methanaminium inner salt] (PolyCMB), and a random copolymer of CMB and n-butyl methacrylate, Poly(CMB-r-BMA), with various molecular weights were analyzed in their aqueous solutions and thin film with contours of O-H stretching of Raman and attenuated total reflection infrared (ATR-IR) spectra, respectively. The relative intensity of the collective band (C value) corresponding to a long-range coupling of O-H stretchings of the Raman spectra for aqueous solution of Poly(CMB-r-BMA) was very close to that for pure water, which is in contrast with the smaller C value in aqueous solution of ordinary polyelectrolytes. The number of hydrogen bonds collapsed by the presence of one monomer residue (N-corr value) of PolyCMB and Poly(CMB-r-BMA) (CMB, 45 mol %) (M-w 1.14 x 10(4) and 1.78 x 10(4), respectively) could be calculated from the C value. The N-corr values were much smaller than those for ordinary polyelectrolytes and close to those for nonionic water-soluble polymers such as poly(ethylene glycol) and poly(N-vinylpyrrolidone). Furthermore, a water-insoluble Poly(CMB-r-BMA) with a large BMA content (M-w = 347 kD, CMB 27 mol %) could be cast as a thin film (thickness, ca 10 mu m) on a ZnSe crystal for the ATR-IR analyses. At an early stage of sorption of water into the Poly(CMB-r-BMA) film, the O-H stretching band of IR spectra for the water incorporated in the film was similar to that for free water, which is in contrast with the drastic change in the O-H stretching band of water incorporated in polymer films such as poly(methyl methacrylate) (PMMA) and poly(n-butyl methacrylate) (PBMA). The theoretical vibrational frequency for water molecules hydrating a betaine molecule calculated by using a density functional method supported the experimental results, The adhesion of human platelets to Poly(CMB-r-BUA) films was much less than that to PMMA and PBMA. With an increase in the content of CMB residue, the number of platelets adhered to the Poly(CMB-r-BMA film drastically decreased and then gradually increased, probably due to the increase in the roughness of the film surface. These results suggest that the carboxybetaine monomer residues with a zwitterionic structure do not significantly disturb the hydrogen bonding between water molecules in both aqueous solution and thin film systems, resulting in the excellent blood-compatibility of the carboxybetaine polymers.