Synthesis and characterization of mesoporous hydroxyapatite powder by microemulsion technique

The mesoporous hydroxyapatite (HAP) powder was synthesized by using the microemulsion (hexadecyltrimethyl ammonium bromide (CTAB)/cyclohexane/n-octyl alcohol) system. The optimal ratios of concentrations of CTAB, cyclohexane and n-octyl alcohol in the microemulsion on morphology of the HAP were studied. The effects of pHs and calcination temperatures on the phase composition of the HAP powder were discussed. The phase composition, morphology, mesoporous structure and the optical density (OD) were characterized and confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), N2 adsorption–desorption isotherms and Multiskan Spectrum, respectively. We further investigated the effect of the HAP powder with meso-structure on the proliferation of bone marrow mesenchymal stem cells (BMSCs) and MC3T3 in vitro, and in vitro study of drug release of mesoporous HAP powder. Through the optimized microemulsion system (CTAB 25 g/L/cyclohexane 125 mL/L/n-octyl alcohol 250 mL/L) at pH of 11.0, the mesoporous HAP was formed. The specific surface area of the HAP powder product is 13.62 m2/g with an average pore size of 19.56 nm after calcinating at 850 °C.