A phosphate-dependent shift in redox state of cerium oxide nanoparticles and its effects on catalytic properties

    Authors

    S. Singh; T. Dosani; A. S. Karakoti; A. Kumar; S. Seal;W. T. Self

    Comments

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    Abbreviated Journal Title

    Biomaterials

    Keywords

    Cerium oxide nanoparticles; Oxidative stress; Catalysis; Redox active; nanomaterials; Reactive oxygen species; SUPEROXIDE-DISMUTASE; CYTOTOXICITY; MEDIA; LOCALIZATION; PHOSPHORUS; NANOCERIA; Engineering, Biomedical; Materials Science, Biomaterials

    Abstract

    Cerium oxide nanoparticles (CeNPs) have shown promise as catalytic antioxidants in cell culture and animal models as both superoxide dismutase and catalase mimetics. The reactivity of the cerium (Ce) atoms at the surface of its oxide particle is critical to such therapeutic properties, yet little is known about the potential for a protein or small molecule corona to form on these materials in vivo. Moreover Ce atoms in these active sites have the potential to interact with small molecule anions, peptides, or sugars when administered in culture or animal models. Several nanomaterials have been shown to alter or aggregate under these conditions, rendering them less useful for biomedical applications. In this work we have studied the change in catalytic properties of CeNPs when exposed to various biologically relevant conditions in vitro. We have found that CeNPs are resistant to broad changes in pH and also not altered by incubation in cell culture medium. However to our surprise phosphate anions significantly altered the characteristics of these nanomaterials and shifted the catalytic behavior due to the binding of phosphate anions to cerium. Given the abundance of phosphate in biological systems in an inorganic form, it is likely that the action of CeNPs as a catalyst may be strongly influenced by the local concentration of phosphate in the cells and/or tissues in which it has been introduced. (C) 2011 Elsevier Ltd. All rights reserved.

    Journal Title

    Biomaterials

    Volume

    32

    Issue/Number

    28

    Publication Date

    1-1-2011

    Document Type

    Article

    Language

    English

    First Page

    6745

    Last Page

    6753

    WOS Identifier

    WOS:000293941400011

    ISSN

    0142-9612

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