Abstract
Hydroxyapatite (HA) and HAβalumina (HA/Al~2~O~3~) composites, with Al~2~O~3~ contents of 5, 10, 20, and 30%, were synthesized using a wet precipitation method and sintered at 900 and 1300Β°C. We investigated the effect of sintering temperature and relative concentration of HA and Al~2~O~3~ on the chemical composition, surface morphology, and cytotoxicity of the composite powders. The XRD results show that in the 1300Β°C composites, HA partially decomposed into CaO which combined with Al~2~O~3~ to form different calcium aluminates. For the 900Β°C composites the CaO phase was not detected, though a Ca/P ratio larger than 1.67 measured by XPS suggests that CaO was present in trace amounts. SEMβEDX analysis indicated that the HA microstructure was affected by the sintering temperature, and this HA is present on the surface of Al~2~O~3~ particles. The cytotoxicity of the composites was assessed indirectly using the MTT assay. The shortβterm effect of leachables was quantified by exposing a L929 mouse fibroblast cell line to the degradation products released by the composites after immersion in the cell culture medium. Degradation products were less toxic to Lβ929 at lower extract concentrations (10, 50%) than at 100% concentration. Cell viability was also influenced by leachable size. Β© 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007