The Role of Cerium Redox State in the SOD Mimetic Activity of Nanoceria
Document Type
Article
Publication Date
6-1-2008
Description
Cerium oxide nanoparticles (nanoceria) have recently been shown to protect cells against oxidative stress in both cell culture and animal models. Nanoceria has been shown to exhibit superoxide dismutase (SOD) activity using a ferricytochrome C assay, and this mimetic activity that has been postulated to be responsible for cellular protection by nanoceria. The nature of nanoceria's antioxidant properties, specifically what physical characteristics make nanoceria effective at scavenging superoxide anion, is poorly understood. In this study electron paramagnetic resonance (EPR) analysis confirms the reactivity of nanoceria as an SOD mimetic. X-ray photoelectron spectroscopy (XPS) and UV-visible analyses of nanoceria treated with hydrogen peroxide demonstrate that a decrease in the Ce 3+/4+ ratio correlates directly with a loss of SOD mimetic activity. These results strongly suggest that the surface oxidation state of nanoceria plays an integral role in the SOD mimetic activity of nanoceria and that ability of nanoceria to scavenge superoxide is directly related to cerium(III) concentrations at the surface of the particle.
Citation Information
Heckert, Eric; Karakoti, Ajay S.; Seal, Sudipta; and Self, William T.. 2008. The Role of Cerium Redox State in the SOD Mimetic Activity of Nanoceria. Biomaterials. Vol.29(18). 2705-2709. https://doi.org/10.1016/j.biomaterials.2008.03.014 PMID: 18395249 ISSN: 0142-9612