Grantee Research Project Results
Engineering a Greener Future One Carbon Nanotube at a Time: An In-Depth Study of Non-Toxic Single Walled Carbon Nanotube DesignEPA Grant Number: FP917167
Title: Engineering a Greener Future One Carbon Nanotube at a Time: An In-Depth Study of Non-Toxic Single Walled Carbon Nanotube Design
Investigators: Pasquini, Leanne Marie
Institution: Yale University
EPA Project Officer: Zambrana, Jose
Project Period: September 1, 2010 through August 31, 2013
Project Amount: $111,000
RFA: STAR Graduate Fellowships (2010)
Research Category: Academic Fellowships , Fellowship - Science & Technology for Sustainability: Green Engineering/Building/Chemistry/Materials
While the nanotechnology industry continues to expand, there remains uncertainty surrounding predicted environmental and human health risk upon exposure to various nanomaterials. It is imperative that research be conducted that brings assurance to the future incorporation of potentially harmful materials into consumer goods. It is known that several nanomaterials, in particular SWNTs, exhibit toxic effects. Research has also shown that certain chemical manipulations of the nanotube surface can decrease their toxicity. This aspect is of interest to the current work intended to facilitate safer design of carbon nanomaterials for the purpose of eliminating potential environmental and human health implications.
Advances in nanotechnology promise improved performance and novel applications in fields ranging from electronics to medicine. Studies report a variety of toxic responses upon exposure to nanomaterials, yet there is no cohesive body of research to verify the proposed human health and environmental threat. This project will contribute to filling the void in comprehensive research and determine how engineered material modifications can decrease toxicity while maintaining the material’s applicability.
Full characterization of purchased and purified pristine unfunctionalized SWNTs will provide the basis of comparison for future surface modified tubes. Characterization techniques will include Thermogravimetric Analysis (TGA), Raman Spectroscopy, Zeta Potential, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), and X-Ray Photoelectron Spectroscopy (XPS). Purified pristine tubes will be used as the starting material in a variety of chemical reactions that will modify the surface with desired functional groups. Characterization of these tubes using the techniques mentioned will elucidate the success and extent of surface functionalization. A fluorescent bacterial assay using E. coli K-12 exposed to the various SWNT samples will provide data for a comparative bacterial toxicity study. Physicochemical properties of the functionalized tubes are dependent upon the pH and ionic strength and composition of a given environment. Therefore, a systematic study will be conducted to see how such changes will affect the biotoxicity.Expected Results:
Full characterization of each tube sample will elucidate the physical and chemical differences among the pristine and functionalized tubes. It is anticipated that overall bacterial cell death will decrease with the addition of certain surface functional groups and will vary depending on the properties and extent of the chemical modifications. In addition, it is likely that changes in environmental conditions, such as pH and ionic strength and composition, will alter the bacterial toxicity, as many of the surface modifications have acid base characteristics.
Potential to Further Environmental/Human Health Protection
The research findings will help to fill the void in information surrounding the toxicity of carbon nanotubes and offer a standard methodology that may be extrapolated to further toxicity studies. As the number and variety of nanomaterials entering consumer goods continue to grow, increased human and environmental exposure is inevitable. More comprehensive information regarding nanomaterial toxicity will empower scientists and engineers to formulate a design scheme for future safe manufacture of nanomaterials.
nanotechnology, carbon nanotubes, toxicity, environment, human health, E. coli, characterization, green design,