Diameter effects on cytotoxicity of multi-walled carbon nanotubes

In this work, we focus on the diameter effects on cytotoxicity of different diametered multi-walled carbon nanotubes (MWNTs). Cellular viability, phagocytotic ability, and apoptosis of guinea pig alveolar macrophages (AM) exposed to MWNTs were studied. MWNTs in smaller diameter showed less cytotoxicity than the larger ones at the same dosage. The phagocytosis ability of AM was partially impaired when the concentration of MWNTs was up to 20 microg/ml, where a further characteristic feature of AM apoptosis was observed. The results indicate that MWNTs in different diameters exhibited quite different cytotoxicity, and for the first time revealed the diameter-effect of MWNTs on cytotoxicity.