Temperature-sensitive micrometer-thick layers of hyaluronan grafted on microspheres
Temperature-sensitive micrometer-thick layers of hyaluronan grafted on microspheres
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DOI：
10.1021/ja0537474
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发表时间：
2006-02-01
影响因子：
15
通讯作者：
Addadi, L
中科院分区：
文献类型：
--
作者：
Joester, D;Klein, E;Addadi, L
巨型聚电解质糖胺聚糖透明质酸 (1-10 MDa) 是多种细胞的细胞周膜的主要成分，是早期细胞粘附事件的重要调节剂和介体。产生软骨的细胞（软骨细胞）的细胞周层厚度可达 5 μm，而非洲爪蟾肾上皮细胞 (M) 的细胞周层厚度可达 2 μm。我们有兴趣生成细胞周皮的模型系统，以便更多地了解透明质酸在生物或人造表面上的结构和功能。我们在此报告了模型系统的合成，其中将厚度高达 2 μm 的配位交联透明质酸涂层共价光接枝到聚苯乙烯微球上。在接近 100% 的相对湿度下，通过环境扫描电子显微镜 (ESEM) 直接对水合涂层进行成像。该过程的关键特征是三价镧系元素阳离子诱导的透明质酸的可逆逆温相变，可用于实现厚层接枝的足够密度。当用镧系元素离子（Gd3+ 或 Tb3+）标记时，微球接枝涂层表现出温度依赖性膨胀。通过湿式 ESEM，我们直接观察到随着温度升高 1 至 11 摄氏度，体积收缩 20%。
The giant polyelectrolyte glycosaminoglycan hyaluronan (1-10 MDa) is a major component of the pericellular coat on a variety of cells, where it is an important modulator and mediator of early cell adhesion events. This pericellular layer can reach 5 mu m thickness on cells that produce cartilage (chondrocytes), and up to 2 mu m on Xenopus laevis kidney epithelial cells (M). We are interested in generating model systems for the pericellular coat in order to learn more about the structure and function of hyaluronan on biological or artificial surfaces. We report here the synthesis of model systems where a coat of coordinatively cross-linked hyaluronan of up to 2 mu m thickness was covalently photografted onto polystyrene microspheres. The hydrated coat was imaged directly by environmental scanning electron microscopy (ESEM) at close to 100% relative humidity. The key feature of the procedure is the reversible reverse-temperature phase transition of hyaluronan induced by trivalent lanthanide cations, which is exploited to achieve sufficient density for grafting of thick layers. The microsphere-grafted coat shows a temperature-dependent swelling when labeled with lanthanide ions (Gd3+ or Tb3+). We directly observed a volume contraction of 20% with increasing temperature between 1 and 11 degrees C by wet-mode ESEM.