NIST, United States
pp. 125 - 128
Keywords: SWCNT, free radical scavengers, DNA oxidation
Carbon nanotubes (CNTs) are remarkable materials in terms of their enhanced thermal and electrical conductivities, tensile strengths and mechanical properties. However, our understanding of the potential environmental, health and safety risks of these novel nanomaterials is incomplete. Many nanomaterials are able to generate free radicals, such as hydroxyl radical, which can attack DNA that is in close proximity under diffusion controlled rates. This presentation will review the experimental findings from a recent exposure study with CNTs in a cell-free model. We demonstrate and propose a mechanistic basis for how single wall carbon nanotubes (SWCNTs) in close contact with oligomeric DNA can act as effective scavengers of free radicals, and thus inhibit the formation and accumulation of DNA lesions. DNA oligomers composed of either (ATT)14 or (GT)20 sequences are used to disperse SWCNTs under controlled ultrasonication conditions. The free radicals generated during the ultrasonication process react with the wrapped oligomers to generate abundant oxidatively-modified adenine, thymine and guanine lesions (measured using mass spectrometry). However, the SWCNT’s effectively scavenge a significant portion of the ultrasonication generated free radicals so that the measured DNA lesion levels are reduced by as much as 80% for certain lesions.