Fig. 3

Each MWCNT material entered the nucleus of BEAS-2B after 24 h of exposure, but nuclear uptake was greater for MWCNT-7 than MWCNT-HT & ND. a Composite image of enhanced dark-field showing the MWCNT fibers in white and the blue fluorescent DAPI stained nuclei. Magnification bar is 10 μm. b Fluorescence only image of A showing areas where blue DAPI stain for DNA has been displaced by the MWCNT-HT material within the nucleus and, therefore, appears as a black hole (white arrows). Magnification bar is 10 μm. c A 3D rendering of a BEAS-2B cell exposed to MWCNT-HT for 24 h overlaid with Raman spectra. The red indicates silica material from the glass microscope slide, the blue indicates nuclear protein, and the green indicates MWCNT-HT material. This image shows the MWCNT-HT material throughout the entire nucleus. d MWCNT-7 white, MWCNT-HT gray, and MWCNT-ND black bars. Partition of MWCNT in the nucleus is given as the number of individual nanotubes per 1000 nuclei. MWCNT-7 partitioning into nuclei at the highest dose of 24 μg/mL were too numerous to accurately count as indicated by the hashed bar. For MWCNT-ND, partition into nuclei at the lowest dose of 0.024 μg/mL was zero. * indicates significantly different from counterpart MWCNT material, p < 0.05; ± SD