title: Toxicity and imaging of multi-walled carbon nanotubes in human macrophage cells.
abstract: Multi-walled carbon nanotubes (MWNTs) have been proposed for use in many applications and concerns about their potential effect on human health have led to the interest in understanding the interactions between MWNTs and human cells. One important technique is the visualisation of the intracellular distribution of MWNTs. We exposed human macrophage cells to unpurified MWNTs and found that a decrease in cell viability was correlated with uptake of MWNTs due to mainly necrosis. Cells treated with purified MWNTs and the main contaminant Fe(2)O(3) itself yielded toxicity only from the nanotubes and not from the Fe(2)O(3). We used 3-D dark-field scanning transmission electron microscopy (DF-STEM) tomography of freeze-dried whole cells as well as confocal and scanning electron microscopy (SEM) to image the cellular uptake and distribution of unpurified MWNTs. We observed that unpurified MWNTs entered the cell both actively and passively frequently inserting through the plasma membrane into the cytoplasm and the nucleus. These suggest that MWNTs may cause incomplete phagocytosis or mechanically pierce through the plasma membrane and result in oxidative stress and cell death.
authors.affiliation: The Nanoscience Centre, University of Cambridge, 11 JJ Thompson Avenue, Cambridge CB3 0FF, UK.
authors.forename: Crystal
authors.initials: C
authors.lastname: Cheng
authors.forename: Karin H
authors.initials: KH
authors.lastname: Müller
authors.forename: Krzysztof K K
authors.initials: KK
authors.lastname: Koziol
authors.forename: Jeremy N
authors.initials: JN
authors.lastname: Skepper
authors.forename: Paul A
authors.initials: PA
authors.lastname: Midgley
authors.forename: Mark E
authors.initials: ME
authors.lastname: Welland
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Porter
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000633:toxicity; D002470:Cell Survival; D002478:Cells, Cultured; D055032:Electron Microscope Tomography; D005290:Ferric Compounds / Q000737:chemistry / Q000633:toxicity; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000648:ultrastructure; D008422:Materials Testing; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity / Q000648:ultrastructure; D009336:Necrosis; D010587:Phagocytosis / Q000502:physiology
chemical_list: D001672:Biocompatible Materials; D005290:Ferric Compounds; D037742:Nanotubes, Carbon; C000499:ferric oxide