Synthesis and cellular biocompatibility of two kinds of HAP with different nanocrystal morphology

Two kinds of hydroxyapatite (HA) with different nanocrystal morphology were obtained via a simple aqueous precipitation method under different reactants molar ratios. Under Ca/P molar ratio of 1.67/1, rod-like crystal was produced, while under Ca/P molar ratio of 1.80/1, spherical crystal was produced. The spherical crystal was 40-60 nm in diameter, while the rod-like crystal was 40-55 nm in diameter and 79-100 nm in length. The influence of HA nanocrystal morphology on osteoblasts growth was assayed by MTT method and SEM. The results indicated that there was a significantly higher absorbency value on the surface of HA with spherical crystal in MTT assay than the latter. In the process of SEM observation, it is found that osteoblasts spread out a large quantity of nano-filopodias on spherical crystal surface, thus exhibiting much more active cell morphology. In conclusion, HA with spherical nanocrystal showed more favorable properties than that with rod-like one for osteoblasts.