Antioxidant cerium ions-containing mesoporous bioactive glass ultrasmall nanoparticles: Structural, physico-chemical, catalase-mimic and biological properties

The multifunctional biological properties of Ce ions including antioxidant, anti-inflammatory, antibacterial and anti-cancer effects are very encouraging for development of Ce-containing biomaterials with therapeutic properties. Herein, novel Ce3+/Ce4+ ions containing mesoporous bioactive glass ultrasmall nanoparticles (Ce-BGn) were prepared by a facile one-pot ultrasound-assisted sol-gel method. Interestingly, Ce2O3 incorporation exerted a significant influence on the particle size and textural properties of mesoporous BGn (SiO2 – CaO binary glass system). Ce-BGn exhibited ultrasmall nanoparticle size (< 30 nm), mesoporous texture (pore size up to 2.82 nm and pore volume up to 0.191 cm3/g) and large specific surface area ca. 132.9 m2/g. Notably, in situ formation of CeO2 nanospheres (3–6 nm) was detected at the surface and in the amorphous glass matrix of mesoporous Ce-BGn. Importantly, X-ray photoelectron spectroscopy (XPS) revealed the presence of 72.57 % Ce3+ and 27.43 % Ce4+ at the surface of mesoporous Ce-BGn with Ce3+/Ce4+ ratio = 2.66. Furthermore, mesoporous Ce-BGn exhibited high catalase-mimic activity and showed sustained release of Ce (2.5–32 ppm), Ca (85–327 ppm) and Si (54–200 ppm) ions within 4 weeks along with excellent bone-like hydroxyapatite formation. Finally, the in vitro biological behavior of mesoporous Ce-BGn in cell cultures of human skin fibroblasts (HSF) revealed that mesoporous Ce-BGn (with concentrations up to 300 μg/mL) possess good cyto-biocompatibility. Taken together, novel ultrasmall mesoporous Ce-BGn showed remarkable catalase-mimic activity via surface containing Ce3+/Ce4+ ions which can scavenge ROS (Ce3+↔ Ce4+) and decompose H2O2 molecules into H2O and O2. In addition to that, Ce-BGn demonstrated sustained release of bioactive ions (Ce, Ca and Si), excellent bone-like hydroxyapatite formation and good cyto-biocompatibility.