Mesoporous bioactive glasses doped with cerium: Investigation over enzymatic-like mimetic activities and bioactivity

In this work, we investigate the ability of mesoporous bioactive glasses (MBGs) modified with cerium ions (Ce3+/Ce4+) to act as catalase and superoxide dismutase (SOD) mimetic materials. We have previously reported that the catalytic properties of bioactive Ce-containing glasses based on 45S5 Bioglass® and synthesized via melting are influenced by: i) composition (presence/absence of P2O5); ii) Ce3+/Ce4+ molar ratio. The introduction of cerium species drastically decreased the bioactivity in terms of Hydroxyapatite formation during bioactivity tests in vitro. We thus decided to add cerium to MBGs, a class of glasses with improved bioactivity with respect to classical molten glasses. MBGs exhibit a high surface area and their reactivity is increased with respect to the molten glasses; they are able to induce the formation of Hydroxyapatite over the surface within shorter times with respect to the 45S5. The catalase and SOD mimetic activity tests revealed that the Ce-MGBs are able to act as mimetic materials for the two enzymes. Both Infrared Spectroscopy and X-ray diffraction analysis have confirmed the presence of Hydroxyapatite over both 80SiO2-15CaO-5P2O5, and 80SiO2-20CaO MBGs samples modified by 5.3% mol of CeO2; simultaneously the glasses maintain a good catalase activity. Moreover, the 80SiO2-15CaO-5P2O5 potential bioactive glasses showed SOD mimetic activity. These results highlight that it is possible to obtain a glass with both antioxidant and bioactivity properties.