Preparation of hydroxyapatite spheres with an internal cavity as a scaffold for hard tissue regeneration.

Microparticulates are currently regarded as a useful matrix for the delivery of bioactive molecules and tissue cells. Herein, hydroxyapatite (HA) spherical microparticulates with an internal cavity were produced using an oil-in-water emulsion technique. The HA slurry in the organic solvent was formulated into spherical particles in a water bath containing a surfactant. Rapid evaporation of the solvent helped create a cavity within the microparticulates. The microparticulates were heat-treated at 1,200 degrees C to produce bioactive HA particles with a mean size of approximately 363 microm. Osteoblastic cells were observed to spread and grow favorably over the surface as well as within the cavity of the microparticulates. The currently developed HA microparticulates with an internal cavity are considered to be useful as a scaffolding matrix for bone tissue engineering and direct filling skeletal defects.