Almora-Barrios Neyvis, Austen Kat F, de Leeuw Nora H
Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom.
Langmuir. 2009 May 5;25(9):5018-25. doi: 10.1021/la803842g.
In view of the importance of the hydroxyapatite/collagen composite of both natural bone tissue and in synthetic biomaterials, we have investigated the interaction of three constituent amino acids of the collagen matrix with two major hydroxyapatite surfaces. We have employed electronic structure techniques based on the density functional theory to study a range of different binding modes of the amino acids glycine, proline, and hydroxyproline at the hydroxyapatite (0001) and (0110) surfaces. We have performed full geometry optimizations of the hydroxyapatite surfaces with adsorbed amino acid molecules to obtain the optimum substrate/adsorbate structures and interaction energies. The calculations show that the amino acids are capable of forming multiple interactions with surface species, particularly if they can bridge between two surface calcium ions. The binding energies range from 290 kJ mol(-1) for glycine on the (0001) surface to 610 kJ mol(-1) for hydroxyproline on the (0110) surface. The large adsorption energies are due to a wide range of interactions between the adsorbate and surface, including proton transfer from the adsorbates to surface OH or PO(4) groups. Hydroxyproline binds most strongly to the surfaces, but all three amino acids should be good sites for the nucleation and growth of the hydroxyapatite (0110) surface at the collagen matrix.
鉴于羟基磷灰石/胶原蛋白复合材料在天然骨组织和合成生物材料中的重要性，我们研究了胶原蛋白基质的三种组成氨基酸与两种主要羟基磷灰石表面之间的相互作用。我们采用基于密度泛函理论的电子结构技术，研究了甘氨酸、脯氨酸和羟脯氨酸在羟基磷灰石（0001）和（0110）表面的一系列不同结合模式。我们对吸附有氨基酸分子的羟基磷灰石表面进行了完全几何优化，以获得最佳的底物/吸附质结构和相互作用能。计算结果表明，氨基酸能够与表面物种形成多种相互作用，特别是当它们能够在两个表面钙离子之间架桥时。结合能范围从甘氨酸在（0001）表面的290 kJ mol⁻¹到羟脯氨酸在（0110）表面的610 kJ mol⁻¹。较大的吸附能是由于吸附质与表面之间存在广泛的相互作用，包括质子从吸附质转移到表面的OH或PO₄基团。羟脯氨酸与表面的结合最强，但所有三种氨基酸都应该是羟基磷灰石（0110）表面在胶原蛋白基质上成核和生长的良好位点。
