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Effect of different carbon nanotubes on cell viability and proliferation

Carbon nanotubes (CNTs) are a focus of intense research for their potential applications in multiple diverse applications, including innovative biomedical applications. Due to their very recent discovery, little information is available about the biocompatibility and toxicity of this new class of nanoparticle, and a systematic study on biological interference is lacking. Thus, we decided to explore the toxicity of three different types of carbon nanotube, differing in preparation (arc discharge versus catalysed chemical vapour deposition); size (10–50 versus 100–150 nm wide × 1–10 µm long); contaminants (amorphous C, graphite, fullerenes or iron) and morphological type (multi-walled, MW, or single-walled, SW) on human leukemic U937 cells. We found that these carbon nanotubes exert a strong effect on the proliferation of the reporter U937 monocytic cell. However, these CNTs did not significantly affect the cell viability. These results show that CNTs, though not directly exerting a direct cytotoxic effect, are nonetheless able to deeply alter cell behaviour, and thus we recommend thorough analyses to limit health risk due to uncontrolled exposure.