Detailed description:
The theoretical composition of hydroxyapatite is Ca10 (PO4) 6 (OH) 2, Ca / P of 1.67, but due to the processes of preparation, the real composition is quite complex. HA is hexagonal crystal, is L6PC symmetric and P63 / m space group, its structure is a hexagonal prism, with the c axis perpendicular to the plane is a hexagon, a, b-axis angle of 120o;, its lattice parameters is a = 9.43 ~ 9.38Å;, c = 6.88 ~ 6.86Å;, z = 2, unit cell contains 10 Ca2+, 6xPO43-and 2 of OH-. HA surface has a surface of several possible states: (1) When a crystalline surface OH, OH with 2 Ca (Ⅱ) ion is connected, when the HA in aqueous solution, the position of this surface at least in a moment OH vacancy , by two Ca (Ⅱ) ion with a positive charge, forming a suction position, this position can be adsorbed PO43-or phosphate groups on the macromolecule or a carboxyl group. (2) When the Ca ions in the surface of the crystal, since Ca (Ⅰ) and 6 charged negatively charged O atom, when the HA in aqueous solution, the surface of Ca (Ⅰ) position vacancies in a moment, in Ca (Ⅰ) position to form a strong adsorption sites, can absorb Sr3 +, K + and other cations and the group of protein molecules, and in the Ca (Ⅱ) position is the formation of a weaker adsorption sites. (3) PO43-in crystal surface, H2O through hydrogen bonding with PO43-ions.
main application：1.after hydroxyapatite implanted into the bone, because of its good affinity to the bone tissue, can induce undifferentiated mesenchymal cells to differentiate into bone cells, which is directly attached to the surface of hydroxyapatite
2. from the chemical composition, it composed of Calcium and phosphate, these two components are the most common constituent of bone tissue and bone tissue is a crystalline calcium hydroxyapatite and phosphate amorphous form, thus hydroxyapatite stone bone substitute material, not only in composition, but also in the structure of human bone tissue is consistent with calcium, it can be used for artificial joint to replace the bone
3.the bio-ceramic materials clinical application:artificial joint, bone substitute, toothpaste, food and other applications.
