Title

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

Authors

Authors

E. G. Heckert; A. S. Karakoti; S. Seal;W. T. Self

Comments

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Abbreviated Journal Title

Biomaterials

Keywords

free radical; nanoparticle; superoxide; surface analysis; cerium oxide; OXIDE NANOPARTICLES; IN-VITRO; SUPEROXIDE; REDUCTION; SYSTEM; Engineering, Biomedical; Materials Science, Biomaterials

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. (c) 2008 Elsevier Ltd. All rights reserved.

Journal Title

Biomaterials

Volume

29

Issue/Number

18

Publication Date

1-1-2008

Document Type

Article

Language

English

First Page

2705

Last Page

2709

WOS Identifier

WOS:000256144300001

ISSN

0142-9612

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