Effect of magnesium and iron incorporation on the physicochemical properties of a new sol-gel derived glass-ceramic
Résumé
In this work we studied the effect of adding MgO and/or Fe2O3 alone or simultaneously on in vitro bioactivity of a new sol-gel derived glass-ceramic in the system 56% SiO2 – (38 – x – y)% CaO – x% MgO – y% Fe2O3 – 6% P2O5 [(x,y) = (0,0); (6,0); (0,2); (6,2)] wt%. The in vitro bioactivity of the materials was assessed in a simulated body fluid (SBF). The materials characterization by Differential Scanning Calorimetry (DSC), BET analysis, FTIR spectroscopy, XRD analysis, ICP-OES spectroscopy and SEM-EDS, before and after soaking in SBF, showed, an absence of changes in glass transition temperature (Tg) for Mg-doped materials, whereas we recorded an increase in Tg for the material doped with Fe only. A decrease in the ionic exchange kinetic between glass-ceramics and SBF was observed for all doped materials. For the Mg-doped materials, the hydroxyapatite (HA) formation rate was delayed contrary to the Mg-free materials. The detailed interpretation of the mechanism of the effect of Fe and Mg on the bioactivity of the glass-ceramics, with consideration of other explanations given in the literature, gives more understanding of how these chemical elements affect the physicochemical properties of the doped materials. We believe, this will help to define the optimal way to tailor the behavior of such biomaterials for biomedical applications.