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

考察了纳米晶羟基碳酸盐磷灰石对蛋白质的选择性吸附性能和碳酸盐离子周围的局域结构。羟基磷灰石晶格中碳酸盐离子的引入使牛血清白蛋白和β_2-MG的吸附选择性发生了较大的变化。用2D核磁共振波谱分析了碳酸根离子的化学状态。在2D^&lt；13&gt；C{^1H}或^&lt；31&gt；P{^1H}Het-Cor核磁共振谱中观察到至少四个或五个可归属于A位(OH)和B位(PO4^3)碳酸盐离子的峰。由于碳酸根离子在羟基磷灰石晶格的A-和B-位的分布，表面电荷分布和羟基等极性基团的减少特别有利于β_2-MG的吸附，而不利于牛血清白蛋白和致病蛋白如β_2-微球蛋白(β_2-MG)的吸附。随着锌含量的增加，纳米晶尺寸变小，其比表面积也随之增大。此外，虽然比表面积有所增加，但随着锌含量的增加，牛血清白蛋白在锌HAp颗粒上的吸附量减少。随着磷灰石中锌离子含量的增加，牛血清白蛋白的吸附量基本不变，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