Hydroxyapatite nanoparticle prepared by controlled precipitation from aqueous phase

Abstract

Hydroxyapatite nanoparticles (NPs) were prepared by controlled precipitation in the presence of stabilizers that confined growth and inhibited the aggregation of nanoparticles. Electrostatically stabilized NPs were prepared in the presence of sodium citrate; Tween 80 was used for steric stabilization. At low stabilizer concentrations, nanorods were formed of grown together, spheroidal hydroxyapatite NPs of ~20 nm in diameter. The rod length decreased as ether sodium citrate or Tween 80 concentration increased. When Cit^3–/Ca²⁺ = 3mol/mol, platelike NPs were formed 20–45 nm long and ~10 nm wide; for Cit^3–/Ca²⁺ = 4 mol/mol, NPs had sizes of 10–15 nm. At relatively high Tween 80 concentrations (>0.05 mol/L), foamlike structures were obtained.