NANOCRYSTALLINE HYDROXYAPATITE PREPARED AT DIFFERENT PRECURSOR CONCENTRATIONS: THERMAL STABILITY, MORPHOLOGY AND IN VITRO CELLULAR RESPONSE

Hydroxyapatite is widely used for the reconstruction of defective bones due to its similarity with the composition of bone mineral. In this research, nanocrystalline hydroxyapatite (HA) was synthesised using calcium hydroxide and phosphoric acid as starting precursors. Different concentrations of the reactants, viz. 0.5, 1.0, 1.5 and 2.0 molL -1 , were considered to investigate their effect on the thermal stability and morphology of the synthesised HA. The results showed that the synthesised HA exhibited rod-like shaped particles having sizes in the range of 73.4 to 114.5 nm in length and 14.9 to 20.7 nm in width. The HA produced at the reactant concentration of 0.5 and 1.0 molL -1 was thermally stable up to 1200 C and did not exhibit any secondary phase. However, the HA prepared at the 1.5 molL -1 concentration decomposed into tricalcium phosphate at 1000 C while the HA prepared at 2.0 molL -1 decomposed at 1200 C. It was also found that the size of the particles increased with increasing reactant concentrations. The HA produced from the reactant concentration of 1.0 molL -1 was found to be optimum in terms of the powder characteristics and the in vitro cell studies indicated that osteoblast cells proliferated well on the synthesised HA, thus confirming the biocompatible nature of the produced bioceramic.