National Institute of Occupational Safety and Health, Nagao, Tama-ku, Kawasaki, Kanagawa.
Ind Health. 2010;48(4):452-9. doi: 10.2486/indhealth.ms1128.
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 microm and 88 nm, respectively, and fibers longer than 5.0 microm 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 microm. 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.
人们对暴露于碳纳米管的工人的健康后果表示了极大的关注。为了对在含有 0.1%Tween 80 的磷酸盐缓冲盐水中悬浮的多壁碳纳米管（MWCNT）进行气管内滴注研究，对其长度和宽度分布、MWCNT 在悬浮液和肺组织中的分散情况以及金属杂质的 MWCNT 含量进行了研究。扫描电子显微镜（SEM）照片上测量的 MWCNT 纤维的算术平均长度和宽度分别为 5.0 微米和 88 纳米，长度大于 5.0 微米的纤维占测量纤维的 38.9%。动态光散射粒径测量表明，5 分钟的超声处理，加上在悬浮液中添加 Tween 80，可将团聚的 MWCNT 的水动力直径减小到 1.0 微米以下的更细颗粒。SEM 观察显示，MWCNT 在悬浮液中以及滴注后第 1 天的肺泡中分散良好。MWCNT 中的铁、铬和镍的浓度分别为 4400、48 和 17ppm（wt/wt），均低于这些金属引发肺部毒性反应的水平。结果表明，分散良好、长而细的 MWCNT 纤维在肺部表现出类似石棉的致病性。
