Studies Of The Biomineralization Synthesis Of Spherical Hydroxyapatite

Hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂, HA or HAP] can be widely used as the substitution of bone transplantation, and is a significant bio-medicine material. Spherical HA has fine ion exchange capability which can adsorb and reclaim excessive fluorine ion in the drinking water and heavy metal ion in industrial waste water, that can be used as new style environment functional mineral material. But the report about the synthesis of spherical nano and micro HA is few. This paper studied the preparation of spherical nano and micro HA by biomineralization.This study takes Ca(NO₃)₂·4H₂O and (NH₄)₃PO₄·3H₂O as reagents. Sphere-like nano-hydroxyapatite with diameter of 30-50 nm can be synthesized in the presence of a certain concentration (2-6%) polyethylene glycol 6000 (PEG) by biomineralization. With a certain concentration of polyvinylpyrrolidone K₃₀ (PVP) orβ-Cyclodextrin (β-CD) as template, by controlling the concentration of the organics we successfully synthesize the spherical HA by biomineralization. The size of the spherical HA is 30～50 nm and 2.0～3.0μm.The crystal phase of obtained samples was characterized by X-ray fluorescence (XRF), X-ray powder diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Thermogravimetric analyzers-microcomputer differential thermal analyzers (TG-DTA) and Electrical conductivity (EC). It is indicated that with the concentration of PEG increasing the surface energy will enhance, and the spherical HA will form easier to decrease surface energy, that is to say the shape of HA is more likely spherical. The reason of forming spherical HA is possibly different concentration of PVP solution has different stereochemistry. And with special molecule structure, theβ-CD induce the form of spherical micro HA.