Cytotoxicity investigation on cultured human blood cells treated with single-wall carbon nanotubes

The single-wall carbon nanotubes (SWCNTs) are one of the new materials of emerging technologies. They are becoming increasingly studied for the possible applications in electronics, optics and biology. In particular, very promising fields of application are the development of optical biosensors and the intracellular drug delivery. Nevertheless, there is a paucity of information on their toxicological properties and on potential human health risk. In the present study the SWCNTs were investigated for the possible induction of toxicity in human blood cells. Cell growth, viability, apoptosis and metabolic activity were evaluated in proliferating human peripheral blood lymphocytes. In un-stimulated human leukocytes primary DNA damage was also evaluated. SWCNTs concentrations ranging from 1 to 50 mu g/ml were tested, and treatment duration varied from 6 to 72 h, in accordance with the biological target investigated. A statistically significant decrease in cell growth was found in cells treated with the highest concentrations ( 25 and 50 mu g/ml). Such decrease was not associated to cell death or apoptosis, but it was demonstrated to be related to a decrease in metabolic activity, as assessed by resazurin assay. Moreover, treatments of 6 h with SWCNTs concentrations of 1, 5 and 10 mu g/ml failed to induce primary DNA damage on the entire human leukocytes population.