Preparation and Morphology Control of Hydroxyapatite by Aqueous Precipitation

Hydroxyapatite, with excellent biocompatibility, biological activity, and biological affinity, is the main inorganic component of human bones and teeth. It can promote bone tissue regeneration and has important applications in bone tissue engineering fields such as bone defect repair and bone replacement. In this study, calcium acetate solution and diammonium dihydrogen phosphate solution had been mixed to prepare calcium phosphate through aqueous precipitation reaction. The testing results of scanning electron microscopy and X-ray diffraction show that the morphology of the product can be controlled by changing the pH, the temperature, and the method of adding reactant solution dropwise. When the temperature of the reaction system is 20℃, plate-like calcium hydrogen phosphate is mainly obtained; block-like hydroxyapatite is obtained when the temperature rised to 40℃; and needle shaped hydroxyapatite is obtained at 60℃. The length and diameter of two-dimensional hydroxyapatite crystals become smaller when the temperature and the pH value of the reaction system increase.