Preparation of Hydroxyapatite-based Composites and Bone-like Layer Growth and Adhesion of Osteoblast-like Cells on the Composites

Abstract

Porous hydroxyapatite (HAp)/α-tricalcium phosphate (α-TCP) composites were prepared by a colloidal process. After the colloidal process, polymethyl methacrylate (PMMA) was added to the slurry, followed by dehydration. Numerous spherical pores were introduced in the composites by mixing PMMA, which was burned out during sintering. The shape, size and volume fraction of pores could be controlled by those of PMMA added to the composites. Calcium-deficient hydroxyapatite (DAp) was synthesized by hydrolysis of α-TCP at different pH. Ca/P ratio of DAp increased with increasing pH during the hydrolysis. Bone-like crystals were formed on DAp which soaked in SBF in vitro. The adhesion of MC3T3-E1 osteoblast-like cells was also influence by pH. High solubility and negative charge of DAp, especially synthesized at lower pH resulted in the fast formation and the good adhesion.