The Research on the Synthesis and Bioactivity of Carbonate Hydroxyapatites

The composition and structure of carbonated hydroxyapatite (CHA) are much closer to those of inorganic minerals in natural bones. A series of experiments have been conducted to investigate the following aspects: (1) the mechanism of CHA synthesis by precipitation approach; (2) the biocompatibility and stability of CHA coatings. The results showed that an even single phase CHA crystals could be developed from Ca (NO)3-(NH4)2HPO4-NaHCO3-NH4OH system. Lastly, the surface of Ti-based CHA/UHMWPE coatings (2μm) was uniform and continuous with average bond strength of 32 MPa. 60 days after implanting the coatings into animals, the surface of the implanted material was totally covered by newly grown bone tissues whose structure was of no significant difference with normal bones, without changing coatings bond strength greatly. The result of the present work implied CHA coatings have excellent bioactivity and stability.