Bioactive glasses are a class of materials used for bone tissue reparation and regeneration. The inclusion of small amounts of cerium within their matrix adds a very important antioxidant behaviourthat mimics the activity of the catalase enzyme, present in our body, which is effective in preventing the damaging effect of H2O2 .
X ray absorption spectroscopy can be exploited to obtain information on both the structure of the material and the evolution of its chemical state during its reaction with hydrogen peroxide, which can be of great help in improving the design of the material.
By means of EXAFS measurements at the Ce K-edge, performed at BM 08 of the ESRF, we studied the local atomic environment of cerium atoms inside glass matrices of different composition: the Ce-O first cordination distance appears to be contracted with respect to the bulk oxide, in good agreement with a model obtained by MD calculations .
High Energy Resolution Fluorescence Detected (HERFD) XANES is a powerful technique which combines a very high sensitivity to the electronic structure with the possibility of investigating solid-liquid interfaces. Performing in-situ HERFD-XANES measurements at the Ce L3 edge, we followed the real time evolution of electronic structure of Ce ions during the reaction between glasses with different composition and morphology and an acqueous solution of hydrogen peroxide. This investigation, carried on at ID 26 of the ESRF, helped to have a better comprehension of the mechanism of reaction, allowing to have important information about the role of cerium in the catalase mimetic activity of this interesting material.
 V. Nicolini et al., Evidence of Catalase Mimetic Activity in Ce3+/Ce4+ Doped Bioactive Glasses, J. Phys. Chem. B, 2015, 119, 4009−4019
 F. Benedetti et al., Structure of active cerium sites within bioactive glasses, J. Am. Cer. Soc., in press