Contents lists available at ScienceDirect Ceramics International journal homepage: www.elsevier.com/locate/ceramint Mesoporous bioactive glasses doped with cerium: Investigation over enzymatic-like mimetic activities and bioactivity Valentina Nicolini a , Gianluca Malavasi a,* , Gigliola Lusvardi a , Alfonso Zambon a , Francesco Benedetti b,c , Giuseppina Cerrato d , Sergio Valeri b,c , Paola Luches c a Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via Campi 103, 41125, Modena, Italy b Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, via Campi 213/a, 41125, Modena, Italy c Institute Nanoscience - CNR, via Campi 213/a, 41125, Modena, Italy d Department of Chemistry & NIS-Interdept. Centre, University of Turin, via P. Giuria 7, 10125, Turin, Italy ARTICLE INFO Keywords: Mesoporous bioactive glasses Catalase mimetic activity Superoxide dismutase mimetic activity XPS FTIR XRD ABSTRACT In this work, we investigate the ability of mesoporous bioactive glasses (MBGs) modified with cerium ions (Ce 3+ /Ce 4+ ) 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 P 2 O 5 ); ii) Ce 3+ /Ce 4+ molar ratio. The in- troduction 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 80SiO 2 –15CaO–5P 2 O 5 , and 80SiO 2 –20CaO MBGs samples modified by 5.3% mol of CeO 2 ; simultaneously the glasses maintain a good catalase activity. Moreover, the 80SiO 2 –15CaO–5P 2 O 5 potential bioactive glasses showed SOD mimetic activity. These results highlight that it is possible to obtain a glass with both antioxidant and bioactivity properties. 1. Introduction In the field of bioactive glasses there is an increasing focus on the study of mesoporous glasses [1,2], a class that show high bioactivity due to their high surface area [3–5]. These glasses are able to promote the formation of Hydroxyl-apatite/Hydroxyl-Carbonate-Apatite (HA/ HCA) in in vitro bioactivity tests at shorter times compared to both the molten bioactive glasses (e.g. Hench's 45S5 Bioglass ® ) and the classic sol-gel bioactive glasses [1]. In addition, recent studies are dedicated to obtain bioactive glasses with additional properties, e.g. antioxidant properties, interesting to help the recovery after surgery [6,7]. Studies in this direction have already been performed, modifying the compo- sition of molten bioactive glasses with cerium oxide [8–10], which has well known antioxidant activity when in the form of nanoparticles [11–13]. The results of these studies have shown that molten bioactive glasses based on the 45S5 composition doped with cerium oxide are able to mimic the function that catalase and super oxide dismutase (SOD) enzymes carries out in the human body [14]. Unluckily, the addition of CeO 2 to the composition of the molten bioactive glasses causes a decrease in their bioactivity [8–10]. Catalase degrades hydrogen peroxide, defined as a reactive oxygen species (ROS), into oxygen and water [15] while SOD catalyze the dismutation of superoxide ions (a “free radical” and the most common ROS) into oxygen and hydrogen peroxide; the latter will be then de- graded by catalase. Both catalase and SOD enzymes are thus important in the disruption of ROS (i.e. free radicals) in the human body, in particular during the recovery after a surgery, when the production of free radicals is boosted [16,17]. In this scenario, a biomaterial able to assist human enzymes to disrupt the free radicals in excess would be of interest for the implantation science. It is well known that the ability of nanoceria (nanoparticles of CeO 2, CeONPs) to show catalase or SOD mimetic activity depends on the molar ratio between Ce 3+ and Ce 4+ on the surface of the nanoparticles [11,18–20]. In particular, a more significant catalase-like activity of https://doi.org/10.1016/j.ceramint.2019.07.080 Received 30 May 2019; Accepted 7 July 2019 * Corresponding author. E-mail address: gianluca.malavasi@unimore.it (G. Malavasi). Ceramics International 45 (2019) 20910–20920 Available online 09 July 2019 0272-8842/ © 2019 Elsevier Ltd and Techna Group S.r.l. All rights reserved. T