·OH-Free Catalytic Decomposition of H₂O₂ by GdVO₄:Eu³⁺ Nanoparticles

Abstract

H2O2 is known to be one of the initiators provoking biomolecules (lipids and proteins) oxidation and cell mutation and death. In this context, molecules, which can react with H2O2 without generating free radicals such as hydroxyl radicals (·OH), are of special interest as effective preventive antioxidants. In the present study, we report on GdVO4:Eu3+ nanoparticles (NPs) as prospective preventive nanozymes. Synthesized GdVO4:Eu3+ NPs were characterized by TEM, HR-TEM, XRD, SAXS, and XPS methods. It has been revealed that in water solutions GdVO4:Eu3+ NPs are in the form of individual crystalline spheroids with l = 12.1 ± 1.23 nm and d = 5.76 ± 0.68 nm. Using the optical spectroscopy technique, the possibility for Fenton- and CAT-like reactions in water solutions containing GdVO4:Eu3+ NPs has been analyzed. The protective effect of GdVO4:Eu3+ NPs from H2O2-induced oxidative stress has been estimated using rat hepatocytes and analyzing changes in cells’ mitochondrial potential. It was concluded that the main mechanism of H2O2 decomposition both in aqueous solutions and biological milieu is rather associated with CAT-like reactions that ensure the V4+/V5+ and V3+/V4+ redox cycling.