The role of cerium redox state in the SOD mimetic activity of nanoceria

Abstract 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...

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Bibliographic Details
Published in:Biomaterials 2008-06, Vol.29 (18), p.2705-2709
Main Authors: Heckert, Eric G, Karakoti, Ajay S, Seal, Sudipta, Self, William T
Format: Article
Language:English
Subjects:
Advanced Basic Science
Biocompatible Materials - chemistry
Biocompatible Materials - metabolism
Biomimetic Materials - chemistry
Biomimetic Materials - metabolism
Cerium - chemistry
Cerium - metabolism
Cerium oxide
Dentistry
Electron Spin Resonance Spectroscopy
Free radical
Hydrogen Peroxide - chemistry
Nanoparticle
Nanoparticles - chemistry
Oxidation-Reduction
Superoxide
Superoxide Dismutase - metabolism
Surface analysis
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Summary:Abstract 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.
ISSN:0142-9612
1878-5905
DOI:10.1016/j.biomaterials.2008.03.014