Oxygen vacancy enhanced biomimetic superoxide dismutase activity of CeO2-Gd nanozymes

Abstract Cerium oxide-based nanozymes have recently drawn much attention in the field of biomedical and antioxidant applications, because of their unique regenerative or autocatalytic properties. Herein, we studied a biomimetic superoxide dismutase (SOD) nanozyme CeO2-Gd that combined the fluorescence properties of rare earth Gd with the antioxidant property of CeO2 nanoparticles, which was prepared via facile route. The structure and composition of the CeO2-Gd were measured and verified by X-ray powder diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray electron spectroscopy (XPS). Confocal microscopy was used to image cells. Antioxidant performance and cell viability of these nanozymes were demonstrated in vitro BGC-803 cell. CeO2-Gd nanozymes with a higher Ce3+/Ce4+ ratio shows higher superoxide dismutase (SOD) mimetic activity. Their antioxidant activity and fluorescence properties of CeO2-Gd in BGC-803 cancer cells are enhanced by oxygen vacancies generated by doping rare-earth elements Gd. This work may guide the future design of CeO2-Gd-based biomimetic nanozymes for anticancer and antioxidant applications.