Catalytic behaviour of cobalt exchanged hydroxyapatite in the oxidative dehydrogenation of ethane

Several samples of exchanged cobalt/calcium (Co$^{2+}$/Ca$^{2+})$ hydroxyapatite were synthesized and characterised by XRD, IR and UV-visible spectroscopy. The level of Co$^{2+}$/Ca$^{2+}$ exchanged was limited to 1.35 wt% of Co and the Co$^{2+}$ ions incorporated in the phosphate matrix were mainly hosted by octahedral sites. The catalytic activity of these materials was measured in the oxidative dehydrogenation of ethane into ethylene in the 450-550$^{\circ}$C range. The global conversion and the ethylene yield increase with temperature and depend upon the cobalt content. They reached 35% and 22% at 550$^{\circ}$C respectively for a Co wt% of about 1%

Cobalt‐containing spherical glass nanoparticles for therapeutic ion release

Bioactive glass nanoparticles (BGNPs) can be internalized by cells, allowing the intracellular release of dissolution products with therapeutic benefit. Different therapeutic ions can be incorporated into the glass network that can promote angiogenesis via simulation of hypoxia conditions and consequent activation of pro-angiogenic genes. Here, novel monodispersed spherical dense BGNPs were obtained by a modified Stöber method with the SiO2–CaO–CoO composition, with diameters of 92 ± 1 nm, with cobalt as the pro-angiogenic ion. The presence of Co2+ species and the role of Co and Ca as network modifiers in the silica glass were confirmed by X-ray photoelectron spectroscopy and 29Si solid-state magic-angle spinning nuclear magnetic resonance, respectively. Controlled Co2+ ion release was observed in culture media, and no cytotoxicity was observed by (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cell viability assay on human osteosarcoma cells in direct contact with the nanoparticles. This study demonstrated that Co2+ ions can be incorporated into dense and spherical BGNPs, and these materials exhibit great potential as intracellular ion delivery systems with therapeutic properties