Toxicity of Carbon Nanotubes

Handbook of Green Chemistry Volume 8 Green Nanoscience, First Edition. 

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Muller, J., Huaux, F. and Lison, D. (2006) Respiratory toxicity of carbon nanotubes how worried should we be Carbon,... 

Tong, H. et al. (2009) Influence of acid functionalization on the cardiopulmonary toxicity of carbon nanotubes and carbon black particles in mice. Toxicology and Applied Pharmacology, 239 (3), 224—232. 

CNTs have been studied for cancer therapies despite the fact that these have been shown to accumulate to toxic levels within the organs of diverse animal models and different cell lines (Fiorito et al., 2006 Tong and Cheng, 2007). The molecular and cellular mechanisms for toxicity of carbon nanotubes have not been fully clarified. Furthermore, toxicity must be examined on the basis of multiple routes of administration (i.e., pulmonary, transdermal, ocular, oral, and intravenous) and on multiple species mammals, lower terrestrial animals, aquatic animals (both vertebrates and invertebrates), and plants (both terrestrial and aquatic). A basic set of tests for risk assessment of nanomaterials has been put forward (Nano risk framework). 

J. Muller, F. Huaux, J. F. Heilier, M. Arras, M. Delos, J. B. Nagy, and D. Lison, Respiratory toxicity of carbon nanotubes, Toxicol. Appl. Pharmacol. 197, 305-305 (2004). 

Muller, J. (2004), Respiratory toxicity of carbon nanotubes, in Proc. of First International Symposium on Occupational Health Implications of Nanomaterials. 

There has been much concern raised about the toxicity of carbon nanotubes in living systems due to the electronic nature of... 

An initial study of the toxicity of carbon nanotubes and fuUerene implied that fiber-shaped nanomaterials were more toxic than spherical nanomaterials [25]. In the case of the carbon nanotube, its shape appeared to hamper the processes of endo-cytosis and phagocytosis, such that chronic pulmonary toxicity occurred. However, a recent in vitro toxicity study using different sizes of sihca nanomaterials showed spherical nanomaterials be more toxic than rods [68]. The suggested reason for this was that the sihca nanorod aggregated much more easily than the spherical sihca nanomaterials consequently, the large aggregates not only reduced the surface area-to-volume ratio of the nanomaterials but also slowed their rate of cehular uptake. It was also shown to be more difficult for ehiphcal nanomaterials to penetrate the skin layer than spherical ones [98]. Overall, however, the results of these studies indicated that the shape of nanomaterials could indeed affect their toxicity. 

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