Département de Chimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC, Canada H3C 3J7.
Biomacromolecules. 2009 Apr 13;10(4):900-6. doi: 10.1021/bm801423p.
Poly(ethylene glycol) (PEG) arms are grafted onto a cholic acid core via anionic polymerization, yielding star-shaped polymers with a unique asymmetric structure with facial amphiphilicity. Well-defined cholic acid-PEG(4) stars (polydispersity index, ca. 1.05) with tunable molar masses (ca. 1000-13,000) were obtained and characterized by the use of size exclusion chromatography, MALDI-TOF mass spectrometry, NMR spectroscopy, and thermal analysis. The asymmetric star polymers were found to aggregate differently from cholic acid salt. The critical aggregation concentrations of the star polymers were determined by surface tension measurements, and spherical aggregates of the polymers with different PEG chain lengths were observed by transmission electron microscopy using the freeze-fracture etching technique. The elongated aggregates formed by the sodium salt of cholic acid were also observed. The hydrodynamic diameters of the aggregates were also measured using dynamic light scattering technique. The formation of aggregates makes them interesting systems as potential drug carriers.
聚乙二醇（PEG）臂通过阴离子聚合接枝到胆酸核心上，得到具有独特不对称结构和表面两亲性的星形聚合物。通过使用尺寸排阻色谱法、MALDI-TOF 质谱法、NMR 光谱法和热分析，获得了具有可调节摩尔质量（约 1000-13000）和良好定义的胆酸-PEG（4）星形聚合物（多分散指数，约 1.05）。不对称星形聚合物的聚集方式与胆酸盐不同。通过表面张力测量确定了星形聚合物的临界聚集浓度，并通过使用冷冻断裂蚀刻技术的透射电子显微镜观察到具有不同 PEG 链长的聚合物的球形聚集体。还观察到胆酸钠形成的伸长聚集体。使用动态光散射技术测量了聚集体的水动力直径。聚集体的形成使它们成为潜在药物载体的有趣系统。
