Industrial Health
Online ISSN : 1880-8026
Print ISSN : 0019-8366
ISSN-L : 0019-8366
Original Articles
Characteristics of Multiwall Carbon Nanotubes for an Intratracheal Instillation Study with Rats
Mitsutoshi TAKAYAFumio SERITAKazunori YAMAZAKIShigetoshi AISOHisayo KUBOTAMasumi ASAKURANaoki IKAWAKasuke NAGANOHeihachiro ARITOShoji FUKUSHIMA
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2010 Volume 48 Issue 4 Pages 452-459

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Abstract

Much concern has been raised over the health consequences of workers exposed to carbon nanotubes. In order to characterize multi-wall carbon nanotubes (MWCNT) suspended in a phosphate-buffered saline containing 0.1% Tween 80 for an intratracheal instillation study. Length and width distributions of the MWCNT fibers, dispersion of MWCNT in the suspension and in the lung tissue and the MWCNT contents of metal impurities were investigated. Arithmetic mean length and width of the MWCNT fibers as measured on scanning electron microscope (SEM) photographs were 5.0 μm and 88 nm, respectively, and fibers longer than 5.0 μm were 38.9% of all fibers measured. Dynamic light scattering size measurement revealed that 5-min ultrasonication, together with addition of Tween 80 into the suspension, decreased the hydrodynamic diameters of the agglomerated MWCNT to those of finer particles below 1.0 μm. SEM observation showed good dispersion of MWCNT in the suspension, and in the alveoli on Day 1 after instillation. Concentration of iron, chromium and nickel in the MWCNT were 4,400, 48 and 17 ppm (wt/wt), respectively, all of which were below levels that would elicit positive pulmonary toxic responses to these metals. The results suggest that well-dispersed, long and thin MWCNT fibers exhibit asbestos-like pathogenicity in the lung.

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© 2010 by National Institute of Occupational Safety and Health
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