Studing of created structural changes in hydroxyapatite indirect Magnesium and Carbonate addition

Natural hydroxyapatite is nanostructured. Also, there exists a minute amount of magnesium ion in the composition of natural hydroxyapatite. The presence of this ion changesthe stoichiometric hydroxyapatite to more biodegradable nonstoichiometric hydroxyapatite. The doping of magnesium ions into the hydroxyapatite structure, which isof great interest for the developing of artificial bone, was performed starting from a wet chemical synthesis methodusing magnesium chloride 6-hydrate as Mg source. Chemicophysical characterizations tests were carried out onto the synthetic Mg-substituted (~30-70 nm particle size) powders in comparison with carbonated HA (~70-130 nm particle size) and stoichiometric HA (~130 nm particlesize). The crystallite size, the crystallinity index and unit cell parameters of Mg-substituted HA were computed from X-ray diffraction patterns and then compared with stoichiometric HA. The homogeneity of composition was studied with SEM-EDAX technique. Results show thatmagnesium was incorporated in the composition of synthesized hydroxyapatite powder. In addition, presence of magnesium ion in the structure of hydroxyapatite results in reduction of crystallite size and the crystallinity index. The incorporation of magnesium ion in the structure ofhydroxyapatite cause to increase about 0.1% of a-axis and 0.3% reduction of c-axis of HA unit cell parameters in comparison with stoichiometric HA. It seems that low crystallinity of synthetic Mg-doped nonstoichiometric hydroxyapatite makes it more biocompatible and enhances the solubility of the material at the physiological pH values

کلیدواژه ها:

Hydroxyapatite ، Magnesium ، Carbonate ، Stiochiometric ، Fixed matrix