Effect of dispersants of multi-walled carbon nanotubes on cellular uptake and biological responses.
Although there have been many reports about the cytotoxicity of multi-walled carbon nanotubes (MWCNTs), the results are still controversial. To investigate one possible reason, the authors investigated the influence of MWCNT dispersants on cellular uptake and cytotoxicity. Cytotoxicity was examined (measured by alamarBlue(®) assay), as well as intracellular MWCNT concentration and cytokine secretion (measured by flow cytometry) in human bronchial epithelial cells (BEAS-2B) exposed to a type of highly purified MWCNT vapor grown carbon fiber (VGCF(®), Shōwa Denkō Kabushiki-gaisha, Tokyo, Japan) in three different dispersants (gelatin, carboxylmethyl cellulose, and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine). The authors also researched the relationship between the intracellular concentration of MWCNTs and cytotoxicity by using two cell lines, BEAS-2B and MESO-1 human malignant pleural mesothelioma cells. The intracellular concentration of VGCF was different for each of the three dispersants, and the levels of cytotoxicity and inflammatory response were correlated with the intracellular concentration of VGCF. A relationship between the intracellular concentration of VGCF and cytotoxic effects was observed in both cell lines. The results indicate that dispersants affect VGCF uptake into cells and that cytotoxicity depends on the intracellular concentration of VGCF, not on the exposed dosage. Thus, toxicity appears to depend on exposure time, even at low VGCF concentrations, because VGCF is biopersistent.
Institute of Carbon Science and Technology, Shinshu University, Matsumoto, Nagano, Japan. hhaniu@shinshu-u.ac.jp
Hisao
H
Haniu
Naoto
N
Saito
Yoshikazu
Y
Matsuda
Yoong-Ahm
YA
Kim
Ki Chul
KC
Park
Tamotsu
T
Tsukahara
Yuki
Y
Usui
Kaoru
K
Aoki
Masayuki
M
Shimizu
Nobuhide
N
Ogihara
Kazuo
K
Hara
Seiji
S
Takanashi
Masanori
M
Okamoto
Norio
N
Ishigaki
Koichi
K
Nakamura
Hiroyuki
H
Kato
D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004058:Diffusion; D004847:Epithelial Cells / Q000737:chemistry* / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D008422:Materials Testing; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000633:toxicity* / Q000648:ultrastructure; D010316:Particle Size
D037742:Nanotubes, Carbon