Study On The Porous Hydroxy Apatite Containing Magnesium In Ultra-Fine Crystal And The Bioactivity

Porous HA with ultra-fine grain containing Mg was prepared by high-temperature sintering, which Mg had been taken as the hole maker. The effect of the magnesium on the porosity of the porous hydroxyapatite were studied, as well as the effect of the sintering temperature and time on the mechanical properties of the porous hydroxyapatite. The biological activity of porous hydroxyapatite in vitro had been studied. The microstructure and composition of HA were analyzed by TEM, SEM and XRD. The varieties of magnesium ions in SBF were carried out by atomic absorption spectrometry. The biological compatibilities both HA and porous HA had been studied in the paper.The experimental results shows that the porosities of the porous HA increased with the amount of magnesium, and the porosities could be increased more than 62% when the contents of Mg is 20wt%, which were beneficial to the growth of the new bone. The compressive strength and bending strength of the porous HA could be enhanced by in creasing of the sintering temperature and sintering time. The main phase was HA and MgO and the grain size of HA in porous HA was sub-micron when adding pure magnesium into sintering body, which indicated that the Mg were not only to preserve the biological activity of porous material, and also overcome the shortcomings of the grain grow in the course of high-temperature sintering of HA.SBF experiments showed that the surface and fracture of the porous HA could form the calcium phosphate and calcium magnesium phosphate, which illuminated that the porous HA containing magnesium had the ability of forming bone-like apatite. The concentration of magnesium ions were always been in the range between 25 to 50ppm, though with the soaking time longer, which were in the range of the normal human body and in line with the amount of magnesium ions that the body needs .Osteoblasts were trained with Mg-HA materials, MgO-HA materials and pure HA composite materials. The rate of the cell adhesion were to 46% after 24 hours. In 3 days, 6 days, 9 days, the experimental results of the cell proliferation of Tetrazolium salt (MTT) and scanning electron microscopy (SEM) shows that the best of activity of cell of three kinds of materials were that the Mg-HA, then MgO-HA material, and pure HA material was the last.The experimental results of the planting materials in the rabbits show that the porous HA containing magnesium in the body were gradually degraded, and was replaced by a large number of new bone, non-immune inflammation occurred, which had excellent in biocompatibility and osteogenic activity, and a large number of new bone were formed when implanting one month. The porous HA containing magnesium had good ability of inducing bone form and was a promising bone repair scaffolds.