TOXICITY OF METAL OXIDE NANOPARTICLES TO CAENORHABDITIS ELEGANS

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Michael Christoher Armstrong (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Advisor

Xiaoping Pan

Abstract: The increase in manufacturing and use of nanoparticles is expected to elevate levels of exposure to humans and other organisms. Presently there is little understanding of the potential toxic effects of nanoparticle exposure. Nano-sized metal oxides for example may adversely affect biological systems due to their unique physiochemical properties. However current findings are largely inconclusive and need further examination. The purpose of this study is to address the current knowledge gaps in metal oxide nanoparticle toxicity and to provide insight into the molecular mechanisms involved in exposure response. We evaluated the in vivo toxicity of CuO ZnO and TiOâ‚‚ nanoparticles to the soil nematode Caenorhabditis elegans (C. elegans). Metal oxide nanoparticle toxicity was assessed by using nematode mortality fertility and gene expression as endpoints. For toxicity assays age-synchronized worms were exposed to nanoparticle treatments of various concentrations (range: 1-100 mg/L) and then evaluated for potential dose and/or time-dependent effects. The results of the lethality and fertility assays suggest that CuO and ZnO nanoparticles are more toxic than TiOâ‚‚ nanoparticles causing increased nematode mortality as well as reduced offspring yields. Both CuO and ZnO nanoparticles were found to exhibit comparable toxicity to C. elegans within the tested dose range. In addition ZnO nanoparticle-induced expression of select nematode genes was investigated using quantitative real-time PCR (qRT-PCR). Expression analysis revealed that gcs-1 was significantly up-regulated compared to the control after exposure to ZnO nanoparticles. As gcs-1 serves an important role in oxidative stress defense functioning through the p38 mitogen-activated protein kinase (MAPK) pathway these results might provide further insight into the molecular mechanisms involved in the response to metal oxide nanoparticle exposure.

Additional Information

Publication

Thesis

Date: 2012

Keywords

Biology

Subjects

Nanoparticles--Toxicology.

Nanoparticles--Research

Toxicity testing--In vivo

Caenorhabditis elegans

Copper oxide--Toxicity testing

Zinc oxide--Toxicity testing

Titanium dioxide--Toxicity testing

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