Properties of water confined in hydroxyapatite nanopores as derived from molecular dynamics simulations
Properties of water confined in hydroxyapatite nanopores as derived from molecular dynamics simulations
复制标题
DOI：
10.1007/s00214-015-1653-3
复制
发表时间：
2015-04
影响因子：
1.7
通讯作者：
T. Pham;T. Lemaire;E. Capiez-Lernout;M. Lewerenz;Q. To;J. K. Christie;D. Tommaso;N. H. Leeuw;S. Naili
中科院分区：
文献类型：
--
作者：
T. Pham;T. Lemaire;E. Capiez-Lernout;M. Lewerenz;Q. To;J. K. Christie;D. Tommaso;N. H. Leeuw;S. Naili
骨组织的特征是胶原-磷灰石基质内的纳米孔，液体可以在其中存在和流动。然而，对骨内流体流动的描述主要依赖于系统的宏观连续力学处理，因此，这些纳米孔的作用在很大程度上被忽视了。然而，忽略骨体积内流体的纳米级行为可能会导致流体动力学的总体描述出现很大的错误。在这项工作中，我们通过对羟基磷灰石（HAP）的两个平行表面之间的水进行原子分子动力学模拟来研究流体运动的纳米起源，羟基磷灰石是哺乳动物骨骼的主要矿物相。本研究中用于模拟hap -水体系的极化核壳原子间势模型已经通过从头计算和实验数据进行了广泛的评估。计算了承压水的结构特性（对分布函数）、动力学特性（自扩散系数）和输运特性（剪切黏度系数）与纳米孔尺寸和系统温度的关系。分析结果表明，水的动力学和输运性质受到约束的显著影响，这可以解释为水分子与表面的钙离子和磷酸盐离子相互作用导致了水在HAP表面的分层。利用分子动力学模拟，我们还计算了水在HAP表面的滑动长度，这是以前从未报道过的数值。
Bone tissue is characterized by nanopores inside the collagen-apatite matrix where fluid can exist and flow. The description of the fluid flow within the bone has however mostly relied on a macroscopic continuum mechanical treatment of the system, and, for this reason, the role of these nanopores has been largely overlooked. However, neglecting the nanoscopic behaviour of fluid within the bone volume could result in large errors in the overall description of the dynamics of fluid. In this work, we have investigated the nanoscopic origin of fluid motion by conducting atomistic molecular dynamics simulations of water confined between two parallel surfaces of hydroxyapatite (HAP), which is the main mineral phase of mammalian bone. The polarizable core–shell interatomic potential model used in this work to simulate the HAP–water system has been extensively assessed with respect to ab initio calculations and experimental data. The structural (pair distribution functions), dynamical (self-diffusion coefficients) and transport (shear viscosity coefficients) properties of confined water have been computed as a function of the size of the nanopore and the temperature of the system. Analysis of the results shows that the dynamical and transport properties of water are significantly affected by the confinement, which is explained in terms of the layering of water on the surface of HAP as a consequence of the molecular interactions between the water molecules and the calcium and phosphate ions at the surface. Using molecular dynamics simulations, we have also computed the slip length of water on the surface of HAP, the value of which has never been reported before.