Kaflak Agnieszka, Kolodziejski Waclaw
Medical University of Warsaw, Faculty of Pharmacy, Department of Inorganic and Analytical Chemistry, ul. Banacha 1, 02-097 Warszawa, Poland.
Magn Reson Chem. 2008 Apr;46(4):335-41. doi: 10.1002/mrc.2207.
Kinetics of NMR cross-polarization (CP) from protons to phosphorus-31 nuclei was studied in the following samples: mineral of whole human bone, apatite prepared from bone, natural brushite, synthetic hydroxyapatite (hydrated and calcined), and synthetic carbonatoapatite of type B with 9 wt% of CO(3) (2-). In order to avoid an effect of magic angle spinning on CP and relaxation, the experiments were carried out on static samples. Parameters of the CP kinetics were discussed for trabecular and cortical bone tissue from adult subjects in comparison to the synthetic mineral standards. It was found that carbonatoapatite shows similar CP behavior to the bone mineral. Both materials undergo two-component CP kinetics. The fast-relaxing classical component is from the surface of apatite crystals and the slow-relaxing nonclassical component comes from the crystal interior. The components have been unambiguously assigned using inverse CP from phosphorus-31 to protons. The study provides information on a structured water layer, which covers crystal surface of carbonato- and bone apatite. The layer encompasses ca 40% of apatite phosphorus and its thickness is more than ca 2 nm.
在以下样品中研究了核磁共振（NMR）从质子到磷-31核的交叉极化（CP）动力学：整个人类骨骼矿物质、由骨骼制备的磷灰石、天然透钙磷石、合成羟基磷灰石（水合和煅烧）以及含9 wt%碳酸根离子（CO₃²⁻）的B型合成碳酸磷灰石。为避免魔角旋转对CP和弛豫的影响，实验在静态样品上进行。与合成矿物标准相比，讨论了成年受试者小梁骨和皮质骨组织的CP动力学参数。发现碳酸磷灰石的CP行为与骨矿物质相似。两种材料都经历双组分CP动力学。快速弛豫的经典组分来自磷灰石晶体表面，缓慢弛豫的非经典组分来自晶体内部。通过从磷-31到质子的反向CP明确确定了这些组分。该研究提供了关于覆盖碳酸磷灰石和骨磷灰石晶体表面的结构化水层的信息。该层包含约40%的磷灰石磷，其厚度超过约2纳米。
