Preparation of self-organized nano-structured apatite and the protein adsorption property

研究了纳米晶羟基碳酸盐磷灰石的选择性蛋白质吸附性能和碳酸盐离子周围的局部结构。羟基磷灰石晶格中碳酸盐离子的掺入使吸附BSA和β_2-MG的选择性发生了很大的变化。采用二维核磁共振波谱法对掺入的碳酸盐离子的化学状态进行了检测。在2D ^<13>C{^1H}或^<31>P{^1H}的Het-Cor核磁共振波谱中，至少观察到a位（OH）和b位（PO_4^3）中有4或5个可分配给碳酸盐离子的峰。由于碳酸盐离子在羟基磷灰石晶格的a和b位点的分布，表面电荷分布和极性基团（如OH）的减少特别有利于β_2-MG的吸附，而不是BSA的吸附。我们用湿化学方法制备了纳米晶含锌羟基磷灰石（ZnHAp），并研究了其对必需蛋白质的选择性吸附。以牛血清白蛋白（BSA）和致病蛋白如β_2-微球蛋白（β_2-MG）为模型蛋白。随着Zn含量的增加，znhap的晶型变小，其比表面积也随着Zn含量的增加而增大。此外，随着锌含量的增加，BSA在ZnHAp颗粒上的吸附量减少，尽管比表面积增加。随着磷灰石中Zn^<2+>离子含量的增加，BSA的吸附量基本不变，而β_2-MG的吸附量增加

The selective protein adsorption property and the local structure around carbonate ions of nanocrystalline hydroxy-carbonate apatite were examined. Considerable changes in the selectivity in the adsorption of BSA and β_2-MG were observed due to the incorporation of the carbonate ions in hydroxyapatite lattice. The chemical states of the incorporated carbonate ions were examined by the 2D NMR spectroscopy. At least four or five peaks assignable to carbonate ions in A-site(OH) and B-site(PO_4^3) were observed in 2D ^<13>C{^1H} or ^<31>P{^1H} Het-Cor NMR spectroscopy. The surface charge distribution and the decrement of polar groups such as OH groups due to the distribution of carbonate ions in both A-and B-sites of the hydroxyapatite lattice are particularly favorable for β_2-MG adsorption rather than for BSA adsorptionWe prepared nano-crystalline Zn-containing hydroxyapatite (ZnHAp) by the wet-chemical method and examined the selective adsorption of essential proteins, taking bovine serum albumin (BSA) and pathogenic protein such as β_2-microglobulin (β_2-MG) as model proteins. The increase of Zn content led to smaller crystallites and their specific surface area of ZnHAps increased with increasing the Zn content, accordingly. Furthermore, the amounts of BSA adsorption on ZnHAp particles decreased with increasing the Zn content in spite of the increase in the specific surface area. As the Zn^<2+> ion content in the apatites increased, the adsorbed amount of BSA was almost constant, whereas that of β_2-MG increased