Cerium Oxide Nanoparticles are More Toxic than Equimolar Bulk Cerium Oxide in Caenorhabditis elegans

  • M. C. Arnold
  • A. R. Badireddy
  • M. R. Wiesner
  • R. T. Di Giulio
  • J. N. Meyer
Article

DOI: 10.1007/s00244-013-9905-5

Cite this article as:
Arnold, M.C., Badireddy, A.R., Wiesner, M.R. et al. Arch Environ Contam Toxicol (2013) 65: 224. doi:10.1007/s00244-013-9905-5
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Abstract

Engineered cerium oxide nanoparticles (CeO2 NPs) are widely used in biomedical and engineering manufacturing industries. Previous research has shown the ability of CeO2 NPs to act as a redox catalyst, suggesting potential to both induce and alleviate oxidative stress in organisms. In this study, Caenorhabditis elegans and zebrafish (Danio rerio) were dosed with commercially available CeO2 NPs. Non-nano cerium oxide powder (CeO2) was used as a positive control for cerium toxicity. CeO2 NPs suspended in standard United States Environmental Protection Agency reconstituted moderately hard water, used to culture the C. elegans, quickly formed large polydisperse aggregates. Dosing solutions were renewed daily for 3 days. Exposure of wild-type nematodes resulted in dose-dependent growth inhibition detected for all 3 days (p < 0.0001). Non-nano CeO2 also caused significant growth inhibition (p < 0.0001), but the scale of inhibition was less at equivalent mass exposures compared with CeO2 NP exposure. Some metal and oxidative stress-sensitive mutant nematode strains showed mildly altered growth relative to the wild-type when dosed with 5 mg/L CeO2 NPs on days 2 and 3, thus providing weak evidence for a role for oxidative stress or metal sensitivity in CeO2 NP toxicity. Zebrafish microinjected with CeO2 NPs or CeO2 did not exhibit increased gross developmental defects compared with controls. Hyperspectral imaging showed that CeO2 NPs were ingested but not detectable inside the cells of C. elegans. Growth inhibition observed in C. elegans may be explained at least in part by a non-specific inhibition of feeding caused by CeO2 NPs aggregating around bacterial food and/or inside the gut tract.

Supplementary material

244_2013_9905_MOESM1_ESM.jpg (420 kb)
Online Resource 1. Soluble cerium (mg/L) in supernatant from CeO2 NP dosing solutions after 2 h ultracentrifugation (273865 x g) over three days. (JPG 421 kb)
244_2013_9905_MOESM2_ESM.jpg (664 kb)
Online Resource 2. Growth of N2 and sod3 worms treated with CeO2 NPs or H2O2. Asterisks indicate P<0.0001 as determined by Mann-Whitney U-test. (JPG 664 kb)
244_2013_9905_MOESM3_ESM.docx (26 kb)
Online Resource 3-4. (DOCX 27 kb)

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • M. C. Arnold
    • 1
  • A. R. Badireddy
    • 2
  • M. R. Wiesner
    • 2
  • R. T. Di Giulio
    • 1
  • J. N. Meyer
    • 1
  1. 1.Nicholas School of the EnvironmentDuke UniversityDurhamUSA
  2. 2.Pratt School of EngineeringDuke UniversityDurhamUSA

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