Grantee Research Project Results
Final Report: Using Flathead Minnow Microarrays to Test Toxicity of Nanoparticles
EPA Contract Number: EPD08026Title: Using Flathead Minnow Microarrays to Test Toxicity of Nanoparticles
Investigators: Carter, Barbara J.
Small Business: EcoArray Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2008 through August 31, 2008
Project Amount: $69,500
RFA: Small Business Innovation Research (SBIR) - Phase I (2008) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Nanotechnology
Description:
The overall goals of this Phase 1 grant were to employ microarrays to identify differentially expressed genes in fathead minnows after acute exposure to nanotubes. This Phase 1 study of nanotubes should help validate the expediency and affordability of the high-density fathead minnow microarrays for compound screening and use in environmental toxicology. The data were analyzed to determine what pathways in the fathead minnow are affected by exposure to nanotubes. This information should enable us to identify “genetic fingerprints” and to use the database we developed as a tool for identifying contaminants in unknown situations (class prediction), which may lead to useful interpretation of human health issues.
Summary/Accomplishments (Outputs/Outcomes):
We showed that, for the multi-walled carbon nanotubes (MWCNT) that we studied, microarrays clearly identify biological impact through genotypic change, even when there are no obvious changes in phenotype. The MWCNT caused no major changes in phenotype, but more than 400 genes were differentially expressed. We also noted that MWCNT are not easily taken up in water, so we had to use a dispersant, sodium dodecylbenzene sulfonate (NaDDBS) to get enough of the material into water to develop a relevant range of concentrations. We found the following:
- Toxicity. None noted up to the level of 1.0 mg/L (nominal).
- Histopathologies. There were no statistically significant abnormalities detected in the liver, ovary, heart or digestive tract for any of the treatments in either size of MWCNT. The gills of fish exposed to the smaller MWCNT (< 8 nm) showed a statistically significant (p = 0.014) difference in the number of fused lamellae in the 0.1 and 0.3 mg/L doses, and none present in the controls.
- H2O control vs. NaDDBS control. Using the acceptance criteria (p < 0.05 and fold change > 2), there are NO differences in gene expression between the water controls and the NaDDBS controls (2.2. mg/L) for gill or ovary after 48 h exposure to > 50 nm MWCNTs.
- Differential Gene Expression (p < 0.005 and fold change > 2). From the microarray analysis, we observed a substantial transcriptional response to exposure in each of the tissues, with more than 400 genes exhibiting altered expression in each of the tissues. However, there was very little commonality in the transcriptional response of these three tissues to a given MWCNT. In addition, the response of a single tissue (gill) to both sizes of nanotubes showed as many differences as similarities. Overall, the effect of the MWCNTs on FHMs varies with the parameters of dose, nanotube size, and tissue. The majority of the differentially expressed genes from each tissue are involved in the biological process category 0006xxx, regulating transport, transcription and protein functions.
Conclusions:
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
small business, SBIR, EPA, nanoparticles, manufacturing products, industrial products, commercial products, nanomaterials, nanotechnology, aquatic environment, exposure, toxicity, human health, nanotubes, fathead minnow, microstructure, surface properties, industrial waste, aerosols, nanoscale products, by-products, nanotechnology industries, aquatic biota, ingestion, epithelial boundaries, phagocytosis, endocytosis, cellular immunity, intracellular digestion, toxicological testing, environmental contaminants, reproduction, gene microarray, in vitro assay, in vivo assay, in vivo exposure, mechanistic outcome, acute exposure, genetic fingerprints, compound screening, environmental toxicology, scientific discipline, health, toxicology, risk assessments, health risk assessment, genetics, altered gene expression, nanotechnology, toxicologic assessment, genetic analysis, nanochemistry, DNA array, bioinformatics, microarray processing, hybridization,, Health, Scientific Discipline, Toxicology, Genetics, Health Risk Assessment, Risk Assessments, altered gene expression, nanochemistry, genetic analysis, nanotechnology, toxicologic assessmentThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.