Analysis on the Difference between Synthetic Hydroxyapatite and Bone Apatite

The composition and structure of bone apatite and synthetic hydroxyapatite powder prepared by precipitation method, sol-gel method was studied by FTIR, EMPA, AFM in this paper. The results showed that the composition and phase structure of apatite powder prepared by sol-gel method was most similar with that in the bone. The calcium phosphate ratios of apatite prepared by two kinds of wet precipitation was 1.69, and 1.73 respectively. The calcium phosphate ratio of apatite prepared by sol-gel methnd was 1.66. The apatite powder prepared by sol-gel method was hoped to be more bioactive and biocompatible compared with apatite powder prepared by wet precipitation method. The EMPA results proved that the bone consisted of Ca, P, O, Na, Mg, K, Cl,etc elements. The amount of apatite decreased while amount of collagen increased from the outer layer to inner layer of the bone. AFM results showed that HA particle, with the size about 150-450 nm in length, 100-150 nm in width, 15-40 nm in thickness, grown layer upon layer regularly. The long axis was not always parallel to the collagen fiber. The angle between collagen fiber and apatite lamellar was about 30-45 degree.