Accelerated transformation of brushite to octacalcium phosphate in new biomineralization media between 36.5 °C and 80 °C

This study investigated the hydrothermal transformation of brushite (dicalcium phosphate dihydrate, DCPD, CaHPO4 center dot 2H(2)O) into octacalcium phosphate (OCP, Ca-8(HPO4)(2)(PO4)(4)center dot 5H(2)O) in seven different newly developed biomineralization media, all inspired from the commercial DMEM solutions, over the temperature range of 36.5 degrees C to 90 degrees C with aging times varying between 1 h and 6 days. DCPD powders used in this study were synthesized in our laboratory by using a wet-chemical technique. DCPD was found to transform into OCP in the Ca2+, Mg2+, Na+, K+, HCO3- Cl- and H2PO4- containing aqueous biomineralization media in less than 72 h at 36.5 degrees C, without stirring. The same medium was able to convert DCPD into OCP in about 2 h at 75-80 degrees C. again without a need for stirring. Samples were characterized by using powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). (C) 2011 Elsevier B.V. All rights reserved.