Gel-derived materials of a CaO-P2O5-SiO2 system modified by boron, sodium,magnesium, aluminum, and fluorine compounds

Bioactive glass-ceramic materials of the CaO-P2O5-SiO2 system modified by a dding boron, magnesium, sodium, fluorine, and aluminum were obtained using the sol-gel method. Gel-derived materials were produced in the pellet form obtained by compression of powders as well as in coatings on glass slides. The materials obtained were examined in vitro with regard to the ability of calcium phosphate layer to form on the material surface as the result of c ontact with simulated body fluid (SBF). SBF pH changes and calcium solubili ty in this solution were determined and scanning electron microscopy, energ y-dispersive X-ray analysis, and infrared spectroscopy studies were conduct ed before and after contact of the materials with SBF. The gels modified by aluminum were amorphous, whereas the sodium and fluorine additives promote d the bulk crystallization of gel-derived materials. The ability of calcium phosphates to crystallize on the surface of gel-derived materials depended only slightly on the types of additives applied, and the character of this dependence was different from that observed in melted glasses. Moreover, t o estimate the biocompatibility of gel-derived coatings, we examined the pr oliferation, collagen synthesis, adhesion, and morphology of fibroblasts (N RK cells) cultured in the presence of gel-derived materials. The results of these experiments showed that none of the tested materials significantly r educed any cell function. (C) 2000 John Wiley & Sons, Inc. J Biomed Mater l ies, 52, 601-612, 2000.