P. Li et al., EFFECTS OF IONS IN AQUEOUS-MEDIA ON HYDROXYAPATITE INDUCTION BY SILICA-GEL AND ITS RELEVANCE TO BIOACTIVITY OF BIOACTIVE GLASSES AND GLASS-CERAMICS, Journal of applied biomaterials, 4(3), 1993, pp. 221-229
Hydroxyapatite induction by a synthesized pure silica hydrogel was exa
mined in various simulated body fluids (SBFs) having different magnesi
um, calcium, and phosphate ion concentrations as well as pH values. Th
e silica hydrogel generated biologically active apatite on its surface
by taking up calcium and phosphorous ionic groups from a surrounding
SBF that was prepared to emulate the human plasma in inorganic composi
tion. The induction period for apatite nucleation on the surface of th
e silica was largely decreased with the addition of a small amount of
the calcium or phosphate ions to the SBF and with an increase in pH, b
ut increased with the addition of magnesium ion. Bioactivity of bioact
ive materials like Bioglass(R) and glass-ceramic A-W was well interpre
ted in terms of the rate of apatite formation reflected in these resul
ts. Moreover, the results provide the basic knowledge for designing ne
w bioactive materials. (C) 1993 John Wiley & Sons, Inc.