Measuring particle size-dependent physicochemical structure in airborne single walled carbon nanotube agglomerates
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As-produced single-walled carbon nanotube (SWCNT) material is a complex matrix of carbon nanotubes, bundles of nanotubes (nanoropes), non-tubular carbon and metal catalyst nanoparticles. The pulmonary toxicity of material released during manufacture and handling will depend on the partitioning and arrangement of these components within airborne particles. To probe the physicochemical structure of airborne SWCNT aggregates, a new technique was developed and applied to aerosolized as-produced material. Differential Mobility Analysis-classified aggregates were analyzed using an Aerosol Particle Mass Monitor, and a structural parameter Γ (proportional to the square of particle mobility diameter, divided by APM voltage) derived. Using information on the constituent components of the SWCNT, modal values of Γ were estimated for specific particle compositions and structures, and compared against measured values. Measured modal values of Γ for 150 nm mobility diameter aggregates suggested they were primarily composed of non-tubular carbon from one batch of material, and thin nanoropes from a second batch of material – these findings were confirmed using Transmission Electron Microscopy. Measured modal values of Γ for 31 nm mobility diameter aggregates indicated that they were comprised predominantly of thin carbon nanoropes with associated nanometer-diameter metal catalyst particles; there was no indication that either catalyst particles or non-tubular carbon particles were being preferentially released into the air. These results indicate that the physicochemistry of aerosol particles released while handling as-produced SWCNT may vary significantly by particle size and production batch, and that evaluations of potential health hazards need to account for this.
Keywordsaerosol carbon nanotubes differential mobility analysis aerosol particle mass monitor composite nanoparticles occupational health
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- Maynard A.D. (1995). The development of a new thermophoretic precipitator for scanning-transmission electron-microscope analysis of ultrafine aerosol-particles. Aerosol Sci. Technol. 23(4): 521–533Google Scholar
- Maynard A.D., Baron P.A., Foley M., Shvedova A.A., Kisin E.R., Castranova V. (2004). Exposure to carbon nanotube material: Aerosol release during the handling of unrefined single walled carbon nanotube material. J. Toxicol. Environ. Health 67(1): 87–107Google Scholar
- Oberdörster G., A. Maynard, K. Donaldson, V. Castranova, J. Fitzpatrick, K. Ausman, J. Carter, B. Karn, W. Kreyling, D. Lai, S. Olin, N. Monteiro-Riviere, D. Warheit & H. Yang, 2005. Principles for characterizing the potential human health effects from exposure to nanomaterials: elements of a screening strategy. Part. Fiber Toxicol. 2(8): doi:10.1186/1743-8977-2-8Google Scholar
- Rogak S.N., Flagan R.C., Nguyen H.V. (1993). The mobility and structure of aerosol agglomerates. Aerosol Sci. Technol. 18(1): 25–47Google Scholar
- Shvedova A.A., Kisin E.R., Mercer R., Murray A.R., Johnson V.J., Potapovich A.I., Tyurina Y.Y., Gorelik O., Arepalli S., Schwegler-Berry D., Hubbs A.F., Antonini J., Evans D.E., Ku B.K., Ramsey D., Maynard A., Kagan V.E., Castranova V., Baron P. (2005). Unusual inflammatory and fibrogenic pulmonary responses to single-walled carbon nanotubes in mice. Am. J. Physiol.-Lung Cell. Mol. Physiol. 289: 698–708CrossRefGoogle Scholar
- Shvedova A.A., Kisin E.R., Murray A.R., Gandelsman V.Z., Maynard A.D., Baron P.A., Castranova V. (2003). Exposure to carbon nanotube material: Assessment of the biological effects of nanotube materials using human keratinocyte cells. J. Toxicol. Environ. Health 66(20): 1909–1926Google Scholar