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

    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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