Lack of OH in nanocrystalline apatite as a function of degree of atomic order: implications for bone and biomaterials
Lack of OH in nanocrystalline apatite as a function of degree of atomic order: implications for bone and biomaterials
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DOI：
10.1016/s0142-9612(03)00487-3
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发表时间：
2004-01-01
期刊：
影响因子：
14
通讯作者：
Silva, MJ
中科院分区：
文献类型：
--
作者：
Pasteris, JD;Wopenka, B;Silva, MJ
使用激光拉曼微探针光谱，我们表征了几种天然和合成磷酸钙相的羟基化程度和原子顺序状态，包括生物（人骨、加热的人骨、小鼠骨、人和野猪牙本质以及人和野猪牙釉质）、地质和合成来源的磷灰石。人们普遍认为，所有研究的相都是羟基磷灰石，即一种含有 OH 的矿物，其组成为 Ca-10(PO4)(6)(OH)(2)。然而，我们观察到，对于纳米晶体样品，磷灰石晶格中的 OH 掺入减少了。在生物样品中，骨（最纳米结晶的生物磷灰石）的拉曼光谱中未检测到OH带，而牙本质中出现弱OH带，牙釉质中出现强OH带。我们同意其他人使用核磁共振、红外光谱和非弹性中子散射的观点，即与一般医学术语相反，骨磷灰石没有羟基化，因此不是羟基磷灰石。从晶体学角度来看，这一观察是出乎意料的。因此，目前尚不清楚哪些原子占据 OH 位以及晶体内如何保持电荷平衡。对于在拉曼光谱中显示 OH 带的非骨磷灰石，羟基浓度（基于 3572 Deltacm(-1) OH 峰与 960 Deltacm(-1) P-O 磷酸盐峰的面积比）和原子有序度的结晶度（基于 960 Deltacm(-1) P-O 磷酸盐峰的相对宽度）之间存在很强的相关性。样品。我们假设身体在生化上对其不同的磷灰石沉淀物（骨、牙本质、牙釉质）施加特定的原子顺序和结晶度状态（以及羟基浓度），以增强它们执行组织特异性功能的能力。 (C) 2003 Elsevier Ltd. 保留所有权利。
Using laser Raman microprobe spectroscopy, we have characterized the degree of hydroxylation and the state of atomic order of several natural and synthetic calcium phosphate phases, including apatite of biological (human bone, heated human bone, mouse bone, human and boar dentin, and human and boar enamel), geological, and synthetic origin. Common belief holds that all the studied phases are hydroxylapatite, i.e., an OH-containing mineral with the composition Ca-10(PO4)(6)(OH)(2). We observe, however, that OH-incorporation into the apatite crystal lattice is reduced for nanocrystalline samples. Among the biological samples, no OH-band was detected in the Raman spectrum of bone (the most nanocrystalline biological apatite), whereas a weak OH-band occurs in dentin and a strong OH-band in tooth enamel. We agree with others, who used NMR, IR spectroscopy, and inelastic neutron scattering, that-contrary to the general medical nomenclature-bone apatite is not hydroxylated and therefore not hydroxylapatite. Crystallographically, this observation is unexpected; it therefore remains unclear what atom(s) occupy the OH-site and how charge balance is maintained within the crystal. For non-bone apatites that do show an OH-band in their Raman spectra, there is a strong correlation between the concentration of hydroxyl groups (based on the ratio of the areas of the 3572 Deltacm(-1) OH-peak to the 960 Deltacm(-1) P-O phosphate peak) and the crystallographic degree of atomic order (based on the relative width of the 960 Deltacm(-1) P-O phosphate peak) of the samples. We hypothesize that the body biochemically imposes a specific state of atomic order and crystallinity (and, thus, concentration of hydroxyl) on its different apatite precipitates (bone, dentin, enamel) in order to enhance their ability to carry out tissue-specific functions. (C) 2003 Elsevier Ltd. All rights reserved.