Roberts J E, Bonar L C, Griffin R G, Glimcher M J
Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139.
Calcif Tissue Int. 1992 Jan;50(1):42-8. doi: 10.1007/BF00297296.
The properties of bone mineral change with age and maturation. Several investigators have suggested the presence of an initial or "precursor" calcium phosphate phase to help explain these differences. We have used solid state 31P magic angle sample spinning (MASS) nuclear magnetic resonance (NMR) and X-ray radial distribution function (RDF) analyses to characterize 11- and 17-day-old embryonic chick bone and fractions obtained from them by density fractionation. Density fractionation provides samples of bone containing Ca-P solid-phase deposits even younger and more homogeneous with respect to the age of mineral than the calcium phosphate (Ca-P) deposits in the whole bone samples. The analytical techniques yield no evidence for any distinct phase other than the poorly crystalline hydroxyapatite phase characteristic of mature bone mineral. In particular, there is no detectable crystalline brushite [DCPD, CaHPO4 2H2O less than 1%] or amorphous calcium phosphate (less than 8-10%) in the most recently formed bone mineral. A sizeable portion of the phosphate groups exist as HPO4(2-) in a brushite (DCPD)-like configuration. These acid phosphate moieties are apparently incorporated into the apatitic lattice. The most likely site for the brushite-like configuration is probably on the surface of the crystals.
骨矿物质的特性会随着年龄和成熟度而变化。几位研究者提出存在一种初始或“前体”磷酸钙相，以帮助解释这些差异。我们使用了固态³¹P魔角样品旋转（MASS）核磁共振（NMR）和X射线径向分布函数（RDF）分析来表征11日龄和17日龄的胚胎 chick 骨以及通过密度分级从它们中获得的组分。密度分级提供了含有Ca-P固相沉积物的骨样品，这些样品在矿物质年龄方面比全骨样品中的磷酸钙（Ca-P）沉积物更年轻且更均匀。分析技术没有提供除成熟骨矿物质特征性的 poorly 结晶羟基磷灰石相之外任何不同相的证据。特别是，在最新形成的骨矿物质中没有可检测到的结晶透钙磷石[DCPD，CaHPO₄·2H₂O小于1%]或无定形磷酸钙（小于8 - 10%）。相当一部分磷酸基团以透钙磷石（DCPD）样构型的HPO₄²⁻形式存在。这些酸性磷酸部分显然被纳入了磷灰石晶格。透钙磷石样构型最可能的位置可能在晶体表面。
