Synthesis and dispersion of hydroxyapatite nanopowders

Spherical, rod and fibroid hydroxyapatite [HAp, Ca10(PO4)6(OH)2] nanoparticles were prepared and dispersed in aqueous media. Temperature and solution pH were the key factors to synthesis of different morphology and crystallinity. Processing conditions were selected from ternary diagram of pH, temperature and Ca:P ratio. High hydroxyl ion concentration (12.25 ≥ pH ≥ 10.5) and low temperature (298 K) favored isotropic non-confined spherical particles, intermediate concentration (9.5 ≥ pH ≥ 7.75) and low temperature (303 K) initiated the anisotropic growth of rod shaped particles but low concentration (7 ≥ pH ≥ 5.25) and high temperature (353 K) accelerated one-dimensional fibroid morphology. The dispersed HAp–citrate complex exhibited a constant zeta potential and size distribution for six months.