Synthesis and characterization of bioinspired nano-hydroxyapatite by wet chemical precipitation

In this work, nanometric hydroxyapatite was added with mineral traces naturally present in mammalian bones. It was synthesized by wet chemical precipitation using Ca(OH)(2) obtained from eggshells as a precursor. Subsequent calcination was performed at a low temperature of 250 degrees C to remove reaction by-products but avoiding the crystal size transition to micrometric sizes. Synthetic hydroxyapatite crystals exhibited irregular-spherical morphologies with a Feret's diameter ranging from 10 to 90 nm. Most importantly, this hydroxyapatite contains levels of Ca, Mg, P, Na, S, Sr, K, Si, Fe, Al, and Ba, close to those reported for mammalian bones. The analysis of the commercial synthetic hydroxyapatite revealed that its crystals form micrometric-like-flakes clusters that do not have additional ions but only Ca and P.