Cellular uptake of pristine
MWCNTs varies depending on the type
of cell and the choice of dispersant. (a) Combined images from bright
field images and phase-contrast photomicrographs obtained 24 h after
exposure of human malignant pleural mesothelioma cells (MESO-1), human
bronchial epithelial cells (BEAS-2B), and human neuroblasts (IMR-32)
to carbon black (CB, 50 nm diameter) and MWCNTs. Both CB and MWCNTs
were absorbed in the MESO-1 cells and BEAS-2B cells, and localized
around the respective exposure sites, whereas in the case of the IMR-32
cells, both CB and MWCNTs adhered but failed to be absorbed. CB and
MWCNTs were added at 1 μg/mL for the treatment of BEAS-2B cells,
and 10 μg/mL for the treatment of the other cells. Scale bars
= 50 μm. Reprinted with permission from ref (384). Copyright 2011 Nature
Publishing Group. (b) A comparison of cellular uptake in BEAS-2B observed
1 and 24 h after exposure to MWCNTs dispersed using different dispersants.
Cellular uptake was determined in terms of the intensity of side scattered
light (SSC) from MWCNTs absorbed in the cells using a flow cytometer.
The MWCNTs dispersed in gelatin or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were increasingly absorbed over
time, whereas those dispersed in carboxymethylcellulose (CMC) were
little absorbed in the cells. Reprinted with permission from ref (385). Copyright 2011 Dove
Medical Press.