Letter abstract

Nature Nanotechnology 5, 354 - 359 (2010)
Published online: 4 April 2010 | doi:10.1038/nnano.2010.44

Subject Category: Environmental, health and safety issues

Carbon nanotubes degraded by neutrophil myeloperoxidase induce less pulmonary inflammation

Valerian E. Kagan1, Nagarjun V. Konduru1, Weihong Feng1, Brett L. Allen2, Jennifer Conroy3, Yuri Volkov3, Irina I. Vlasova1, Natalia A. Belikova1, Naveena Yanamala4, Alexander Kapralov1, Yulia Y. Tyurina1, Jingwen Shi5, Elena R. Kisin6, Ashley R. Murray6, Jonathan Franks7, Donna Stolz7, Pingping Gou2, Judith Klein-Seetharaman4, Bengt Fadeel5, Alexander Star2 & Anna A. Shvedova6

We have shown previously that single-walled carbon nanotubes can be catalytically biodegraded over several weeks by the plant-derived enzyme, horseradish peroxidase1. However, whether peroxidase intermediates generated inside human cells or biofluids are involved in the biodegradation of carbon nanotubes has not been explored. Here, we show that hypochlorite and reactive radical intermediates of the human neutrophil enzyme myeloperoxidase catalyse the biodegradation of single-walled carbon nanotubes in vitro, in neutrophils and to a lesser degree in macrophages. Molecular modelling suggests that interactions of basic amino acids of the enzyme with the carboxyls on the carbon nanotubes position the nanotubes near the catalytic site. Importantly, the biodegraded nanotubes do not generate an inflammatory response when aspirated into the lungs of mice. Our findings suggest that the extent to which carbon nanotubes are biodegraded may be a major determinant of the scale and severity of the associated inflammatory responses in exposed individuals.

  1. Department of Environmental and Occupational Health, Center for Free Radical and Antioxidant Health, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
  2. Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
  3. Department of Clinical Medicine and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin, Ireland
  4. Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
  5. Division of Molecular Toxicology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
  6. Pathology and Physiology Research Branch, Health Effects Laboratory Division (HELD), National Institute for Occupational Safety and Health (NIOSH) and Department of Physiology and Pharmacology, West Virginia University, Morgantown, West Virginia, USA
  7. Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Correspondence to: Valerian E. Kagan1 e-mail: kagan@pitt.edu


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