Adhesion and Proliferation of Osteoblastic Cells on Hydroxyapatite-dispersed Ti-based Composite Plate

Biocompatibility of a novel and more stable hydroxyapatite (HA)-dispersed titanium (Ti)-based composite was investigated, using the mouse osteoblast precursor cell line MC3T3-E1. Surface of powders and plates was observed by scanning electron microscopy. Distribution of calcium and phosphorus on the surface of the composite was evaluated by an electron beam microanalyzer. Crystal structure was analyzed by X-ray diffractometer. Cell viability was determined by WST-1 assay. HA was stable against the compressive force, shearing stress and sintering heat at 800°C, but it slightly decomposed at 1100°C. With the increase of HA in the composites, the adhesion/proliferation of MC3T3-E1 cells was reduced. The growth inhibition by HA does not seem to be due to materials released from the plate, but rather to the contact to the surface of the plate. Sintering of the HA plate at 1100°C increased the number of attached viable cells. On the other hand, culturing on the synthesized calcium phosphate (apatite containing carbonic acid) increased the number of attached cells to a greater extent. HA inhibits the growth of osteoblastic cells, but sintering at 1100°C changes the surface properties of the composite so as to stimulate cell growth.