Nanotech News

October 31, 2005

Laboratory Safety A Must When Working with Carbon Nanotubes

Single-walled carbon nanotubes (SWCNTs) are proving to be a versatile tool for ferrying drug molecules and imaging agents into cells (see earlier story) and as miniature thermal scalpels or bombs capable of physically destroying cancer cells. And while research has yet to determine the safety of SWCNTs as human therapeutic or imaging agents, new information from a multi-institutional research team raises some concerns for researchers studying these nanomaterials.

Writing in the American Journal of Physiology – Lung Cellular and Molecular Physiology, a team of investigators led by Anna Shvedova, Ph.D., of the U.S. National Institute for Occupational Safety and Health, found that SWCNTs were capable of triggering unusual inflammatory responses in the lungs of mice that inhaled low levels of these materials. The amount of SWCNT that the mice inhaled was equivalent to the maximum exposure to graphite allowed in an occupational setting. The resulting inflammation also led to adverse physical changes in lung tissue, and the treated mice were less able than untreated mice to clear bacteria from their lungs.

Though it is unlikely that patients would ever be exposed to airborne SWCNTs during therapy, the researchers did note that laboratory workers could be exposed to significant levels of airborne nanotubes. During violent mixing of SWCNTs in water using a vortexing instrument, a common laboratory procedure, airborne levels of SWCNTs increased significantly. Repeated exposure to the levels observed could therefore raise the potential for lung toxicity over time.

There is still no data showing how long the observed effects on lung tissue last. Nevertheless, researchers working with SWCNTs would be wise to exercise standard laboratory confinement techniques to minimize their potential exposure to aerosolized carbon nanotubes.

This work is detailed in a paper titled, “Unusual inflammatory and fibrogenic pulmonary responses to single-walled carbon nanotubes in mice.” Researchers from GBTech Inc., NASA-Johnson Space Center, and the University of Pittsburgh also participated in this study. An abstract is available through PubMed.
View abstract.