Multi-walled carbon nanotubes (MWCNT): induction of DNA damage in plant and mammalian cells

Increasing use of multiwalled carbon nanotubes (MWCNT) necessitates an improved understanding of their potential impact on environment health. In the present study we evaluated the genotoxicity of MWCNT on plant and mammalian test systems. Genotoxic responses such as chromosomal aberrations and DNA strand breakages were studied in Allium cepa, human lymphocytes, mouse bone marrow cells and pBR322 plasmid DNA. Results showed that MWCNT could cause chromosomal aberrations, DNA fragmentation and apoptosis in Allium root cells that could be correlated with the internalization of MWCNT in the plant cells. In human lymphocytes significant genotoxic response was observed at the concentration 2 μg/ml. Higher concentrations led to a decrease in values of the tail DNA percent that may be due to the formation of crosslinks. Annexin V-FITC-PI staining indicated only a small percentage of cells were undergoing apoptosis. Genotoxic effects were shown by micronuclei (MN) frequencies in experiments on mouse bone marrow cells. In the cell free DNA system (plasmid pBR322), a strong correlation between DNA strand break and concentration was observed. Based on the findings of the present study MWCNT may have significant impact on genomic activities.