New bioactive glass and changes in porosity during the growth of a carbonate hydroxyapatite layer on glass surfaces

The synthesis of a bioactive glass with a composition (in mole %) SiO2 (55) , CaO (41), P2O5 (4) was carried out by the sol-gel method. The in vitro bi oactivity of this glass was assessed by following the changes in surface co mposition and morphology after soaking in simulated body fluid (SBF) for se veral periods. Also the porosity of the glass was studied by considering th e changes of that porosity when a carbonate hydroxyapatite (CHA) layer grow s on the glass surface. The glass synthesized in this work shows a high deg ree of porosity due to its elevated content in Ca(II), which is released fr om the glass to the media. This dilution of Ca2+, which gives rise to macro pore enhancement together with the saturation of the media, leads to a fast growth of CHA on glass surface and pores.