Relating the physicochemical characteristics and dispersion of multiwalled carbon nanotubes in different suspension media to their oxidative reactivity in vitro and inflammation in vivo

Abstract

Reactive oxygen species (ROS) production is important in the toxicity of pathogenic particles such as fibres. We examined the oxidative potential of straight (50 μm and 10 μm) and tangled carbon nanotubes in a cell free assay, in vitro and in vivo using different dispersants. The cell free oxidative potential of tangled nanotubes was higher than for the straight fibres. In cultured macrophages tangled tubes exhibited significantly more ROS at 30 min, while straight tubes increased ROS at 4 h. ROS was significantly higher in bronchoalveolar lavage cells of animals instilled with tangled and 10 μm straight fibres, whereas the number of neutrophils increased only in animals treated with the long tubes. Addition of dispersants in the suspension media lead to enhanced ROS detection by entangled tubes in the cell-free system. Tangled fibres generated more ROS in a cell-free system and in cultured cells, while straight fibres generated a slower but more prolonged effect in animals.

Keywords::

• Reactive oxygen species
• cell free assay
• macrophages in culture
• bronchoalveolar lavage cells
• carbon nanotubes

Acknowledgments

We thank Dr L. Foucoud for stimulating discussions.

Declaration of interest: This work was supported by the Colt Foundation and the EPSRC (EP/E04204X/1). The authors would like to report no conflict of interests or competing financial interests. The authors are entirely responsible for the content and writing of the manuscript.