2.1.2. Cu-Substituted MBG Nanoparticles

Cu-substituted MBGs nanoparticles (nominal molar ratio Cu/Ca/Si = 2/13/85, hereafter named as MBG\_Cu2%\_SG) were prepared using a base-catalyzed template sol-gel synthesis, following an already optimized protocol [16]. In brief, 6.6 g of CTAB, acting as template, and 12 mL of NH4OH were dissolved in 600 mL of ddH2O under magnetic stirring (350 rpm) for 30 min. Then, 30 mL of TEOS, 4.888 g of Ca(NO3)2 · 4H2O and 0.428 g of CuCl2 were added, and the obtained solution was vigorously stirred for 3 h at room temperature (RT). The powder was collected by centrifugation (Hermle Labortechnik Z326, Hermle LaborTechnik GmbH, Wehingen, Germany) at 10,000 rpm for 5 min, washed twice with ddH2O and once with absolute ethanol. The final precipitate was dried at 70 ◦C for 12 h and calcined at 600 ◦C in air for 5 h at a heating rate of 1 ◦C min−<sup>1</sup> using a Carbolite 1300 CWF 15/5 (Carbolite Ltd., Hope Valley, UK), in order to completely remove CTAB.
