Layani J D, Cuisinier F J, Steuer P, Cohen H, Voegel J C, Mayer I
Unité INSERM U 424, Federation de Recherche Odontologie, 11 rue Human, 67085 Strasbourg Cedex, France.
J Biomed Mater Res. 2000 May;50(2):199-207. doi: 10.1002/(sici)1097-4636(200005)50:2<199::aid-jbm15>3.0.co;2-q.
Aluminum (Al)-containing calcium-deficient carbonated hydroxyapatites were produced by a precipitation method from aqueous solution with carbonate (0-6.1%) and aluminum (0.1-0.5%) concentrations close to those found in biological materials. Two series of apatites were prepared: one at pH 7.0 and another at pH 9. 0. High-resolution electron microscopy has shown that many of them possess structural defects such as screw dislocations, grain boundaries, and central defects. Samples with high carbonate content and high water and high Al(3+) content had a high amount of structural defects. Accordingly, a sample (7Al1) with a relatively high carbonate content (6.1%) and a sample (7Al6) without carbonate but with a relatively high water (2.0 mol) and Al(3+) content (0. 39%) presented the highest amount of structural defects, 54% and 47%, respectively. A sample (7Al13) with a low level of crystalline water (1 mol) and low carbonate (2.5%) showed a small amount of defects. The presence of water associated with Al(3+) induced a high number of crystals having a central defect with a great similarity to the so-called water layer of octacalcium phosphate (OCP). Observed images of all these crystals have shown good correspondence with the computer-simulated image based on the crystal structure of hydroxyapatite, indicating that the addition of Al(3+) and carbonate does not perturb the apatitic structure.
通过沉淀法从水溶液中制备了含铝的缺钙碳酸羟基磷灰石，其中碳酸盐（0 - 6.1%）和铝（0.1 - 0.5%）的浓度接近生物材料中的浓度。制备了两个系列的磷灰石：一个在pH 7.0下制备，另一个在pH 9.0下制备。高分辨率电子显微镜显示，其中许多磷灰石具有结构缺陷，如螺旋位错、晶界和中心缺陷。碳酸盐含量高、含水量高且铝（3+）含量高的样品具有大量结构缺陷。因此，碳酸盐含量相对较高（6.1%）的样品（7Al1）和不含碳酸盐但含水量相对较高（2.0 mol）且铝（3+）含量较高（0.39%）的样品（7Al6）分别呈现出最高的结构缺陷量，分别为54%和47%。结晶水含量低（1 mol）且碳酸盐含量低（2.5%）的样品（7Al13）显示出少量缺陷。与铝（3+）相关的水的存在导致大量晶体具有中心缺陷，这与所谓的磷酸八钙（OCP）的水层非常相似。所有这些晶体的观察图像与基于羟基磷灰石晶体结构的计算机模拟图像显示出良好的对应关系，表明添加铝（3+）和碳酸盐不会扰乱磷灰石结构。
