XRD, SEM-EDS, and FTIR studies of in vitro growth of an apatite-like layeron sol-gel glasses

A glass with a composition (in mole %) of: SiO2 (70), CaO (26), and P2O5 (1 ) was obtained using a sol-gel method. The in vitro bioactivity of the glas s was assessed by determining the changes in surface morphology and composi tion after soaking in simulated body fluid (SBF) for periods of up to 14 da ys at 37 degrees C. X-ray diffraction, scanning electron microscopy, X-ray energy dispersive spectroscopy, and FTIR analyses of the glass surface afte r different soaking periods in SBF demonstrated the growth of an apatite-li ke layer on the glass surface. in the first stage, an amorphous calcium pho sphate layer was formed; after 7 days this surface consisted of spheres, wi th diameters ranging between 2 and 15 mu m, composed of needle-like apatite crystallites (250 x 100 nm) with a crystallinity similar to that of a biol ogical apatite. (C) 1999 John Wiley & Sons, Inc.