A sol-gel synthesis, characterization and in vitro bioactivity of binary, ternary and quaternary bioglasses with high mechanical strength

Bioactive powders of the binary SiO 2 -CaO, ternary SiO 2 -CaO-P 2 O 5 and quaternary systems SiO 2 -CaO-P 2 O 5 -Na 2 O/Mg 2 O were synthesized using a sol-gel route. The gels were converted into bioglasses powders by heat treatments at the temperature of 700°C. The resulting materials were characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Environmental Scanning Electron Microscopy (ESEM) and in vitro bioactivity in acellular Simulated Body Fluid (SBF). The in vitro tests showed that the samples had good apatite-forming ability. Glasses doped with sodium and magnesium show good results in terms of bioactivity and mechanical properties. The results showed that the quaternary glass SiO 2 -CaO-P 2 O 5 -Na 2 O containing Na is the most bioactive, only 6 hours after its immersion in SBF; a layer of hydroxycarbonated apatite (HAC) was deposited on the glass and compressive strength of up to 233.08 MPa with a porosity of 11.02%, due to the presence of the Na 2 Ca 2 Si 3 O 9 phase. Magnesium also affects bioactivity because it has improved from binary to ternary to quaternary doped with magnesium, bioactive from 12h of contact with the SBF.