NMR of Biopolymer-Apatite Composites: Developing a Model of the Molecular Structure of the Mineral-Matrix Interface in Calcium Phosphate Biomaterials
NMR of Biopolymer-Apatite Composites: Developing a Model of the Molecular Structure of the Mineral-Matrix Interface in Calcium Phosphate Biomaterials
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DOI：
10.1021/cm101730f
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发表时间：
2010-11-23
影响因子：
8.6
通讯作者：
Trasler, Christine M.
中科院分区：
文献类型：
--
作者：
Bradley, Joanna V.;Bridgland, Lydia N.;Trasler, Christine M.
纳米颗粒羟基磷灰石（HAPS）复制一些亚纳米长度尺度的硬组织的分子间相互作用的特点已经制备的核磁共振（NMR）结构解析。在酸性多糖（硫酸软骨素、硫酸皮肤素、透明质酸、硫酸葡聚糖、聚半乳糖醛酸）和亲水性聚氨基酸（聚-L-谷氨酸、聚-L-天冬酰胺、聚-L-赖氨酸）的存在下，在生理pH和温度下从稀水溶液中沉淀HAps。HAp在其P-31 NMR性质、X射线粉末衍射中的宽反射以及由含有水和磷酸氢盐的较不有序表面包围的有序结晶核心的共存方面类似于骨。C-13{P-31}旋转回波双共振（REDOR）NMR，探测碳磷接近低于约。1 nm，表明所有的HAps是分子复合材料，其中每个生物聚合物形成密切的分子间缔合与矿物离子。矿物质磷和多糖的环碳、聚-L-谷氨酸和聚-L-天冬酰胺的侧链末端羧酸酯和酰胺羰基以及聚-L-赖氨酸的侧链碳之间的REDOR效应紧密地概括了天然骨中所见的那些。这样的模型HAp-生物聚合物复合材料将被证明是有用的，在生物矿化中的生物聚合物的作用的研究，并在高分辨率的生物矿物结构阐明。
Nanoparticulate hydroxyapatites (HAps) reproducing some of the subnanometre length scale intermolecular interactions characteristic of hard tissue have been prepared for nuclear magnetic resonance (NMR) structural elucidation. HAps were precipitated at physiological pH and temperature from dilute aqueous solutions, in the presence of acidic polysaccharides (chondroitin sulfate, dermatan sulfate, hyaluronic acid, dextran sulfate, polygalacturonic acid), and of hydrophilic poly aminoacids (poly-L-iglutamate, poly-L-asparagine, poly-L-lysine). The HAp resembles that of bone with respect to its P-31 NMR properties, broad reflections in X-ray powder diffraction, and the coexistence of an ordered crystalline core, surrounded by a less ordered surface containing water and hydrogen phosphate. C-13{P-31} rotational echo double resonance (REDOR) NMR, which probes carbon phosphorus proximities below ca. 1 nm, shows that all the HAps are molecular composites in which each biopolymer forms intimate intermolecular associations with mineral ions. REDOR effects between mineral phosphorus and ring carbons of the polysaccharides, and the side-chain terminal carboxylate and amide carbonyls of poly-L-glutamate and poly-L-asparagine, and the side chain carbons of poly-L-lysine, closely recapitulate those seen in native bone. Such model HAp-biopolymer composites will prove useful in studies of the role of biopolymers in biomineralization, and in high resolution biomineral structure elucidation.