Magnesium incorporation into hydroxyapatite
Magnesium incorporation into hydroxyapatite
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DOI：
10.1016/j.biomaterials.2010.11.017
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发表时间：
2011-03-01
期刊：
影响因子：
14
通讯作者：
Smith, Mark E.
中科院分区：
文献类型：
--
作者：
Laurencin, Danielle;Almora-Barrios, Neyvis;Smith, Mark E.
采用多核固体核磁共振、X射线吸收光谱和计算模型研究了镁在羟基磷灰石（HA）中的掺入。对类似于10%镁取代的HA进行了高磁场Ca-43固态核磁共振和Ca K边XAS研究，提供了镁在Ca（II）位置优先取代的直接证据。H-1和P-31固体核磁共振谱表明，在这种取代的磷灰石相中，阴离子的环境是无序的。密度泛函理论（DFT）和原子间势计算镁取代HA结构与这些观察结果一致。事实上，在Ca（II）网站的低水平的Mg的掺入被认为是更有利的能量，从这些优化的结构计算的NMR参数与实验数据是一致的。计算提供了直接洞察HA晶格的结构修改，由于Mg周围的M中心点中心点O距离的强烈收缩。最后，广泛的原子间势的计算也表明，局部集群的镁内的HA晶格是可能发生的。磷灰石中镁环境的这种结构特征将有利于更好地理解这种阳离子的生物学作用。(C)2010爱思唯尔有限公司版权所有。
The incorporation of Mg in hydroxyapatite (HA) was investigated using multinuclear solid state NMR, X-ray absorption spectroscopy (XAS) and computational modeling. High magnetic field Ca-43 solid state NMR and Ca K-edge XAS studies of a similar to 10% Mg-substituted HA were performed, bringing direct evidence of the preferential substitution of Mg in the Ca(II) position. H-1 and P-31 solid state NMR show that the environment of the anions is disordered in this substituted apatite phase. Both Density Functional Theory (DFT) and interatomic potential computations of Mg-substituted HA structures are in agreement with these observations. Indeed, the incorporation of low levels of Mg in the Ca(II) site is found to be more favourable energetically, and the NMR parameters calculated from these optimized structures are consistent with the experimental data. Calculations provide direct insight in the structural modifications of the HA lattice, due to the strong contraction of the M center dot center dot center dot O distances around Mg. Finally, extensive interatomic potential calculations also suggest that a local clustering of Mg within the HA lattice is likely to occur. Such structural characterizations of Mg environments in apatites will favour a better understanding of the biological role of this cation. (C) 2010 Elsevier Ltd. All rights reserved.