Assessing the pulmonary toxicity of single-walled carbon nanohorns

Abstract

Previous studies have suggested that single-walled carbon nanotubes (SWCNTs) may pose a pulmonary hazard. We investigated the pulmonary toxicity of single-walled carbon nanohorns (SWCNHs), a relatively new carbon-based nanomaterial that is structurally similar to SWCNTs. Mice were exposed to 30 µg of surfactant-suspended SWCNHs or an equal volume of vehicle control by pharyngeal aspiration and sacrificed 24 hours or 7 days post-exposure. Total and differential cell counts and cytokine analysis of bronchoalveolar lavage fluid demonstrated a mild inflammatory response which was mitigated by day 7 post-exposure. Whole lung microarray analysis demonstrated that SWCNH-exposure did not lead to robust changes in gene expression. Finally, histological analysis showed no evidence of granuloma formation or fibrosis following SWCNH aspiration. These combined results suggest that SWCNH is a relatively innocuous nanomaterial when delivered to mice in vivo using aspiration as a delivery mechanism.

• Single-walled carbon nanohorns
• nanotoxicology
• aspiration
• inflammatory

Acknowledgements

This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL), managed by UT-Battelle, LLC, for the US Department of Energy under Contract No. DE-AC05-00OR22725. We are indebted to Dr Vincent Castranova of the US National Institute of Occupational Safety and Health for training us in the aspiration and BAL techniques used in this study. We thank Dr David Geohegan of the Materials Science and Technology Division at ORNL for valuable discussion on laser synthesis of SWCNHs during the study. We also thank Dr John Dunlap of the University of Tennessee Knoxville (UTK) for his assistance with SEM imaging and Dr Micheal Karlstad of the Division of Surgical Research at the UTK Graduate School of Medicine for advice and use of his Laboratory.