Nature: Biodegraded carbon nanotubes induce less pulmonary inflammation
Carbon nanotubes can be broken down by neutrophil enzyme myeloperoxidase, reducing the severity of the associated inflammatory responses in exposed individuals, according to a study published online April 4 in Nature Nanotechnology.

Carbon nanotubes consist of a single layer of carbon atoms rolled into a tube with a diameter of only a couple of nanometers.

"Previous studies have shown that carbon nanotubes could be used for introducing drugs or other substances into human cells," said Bengt Fadeel, MD, PhD, associate professor at the Karolinska Institutet in Stockholm.

"The problem has been not knowing how to control the breakdown of the nanotubes, which can cause unwanted toxicity and tissue damage. Our study now shows how they can be broken down biologically into harmless components," added Fadeel.

The current study by a team of Swedish and American scientists showed that endogenous myeloperoxidase enzyme, expressed in neutrophils can break down carbon nanotubes into water and carbon dioxide. The researchers also showed that the biodegraded nanotubes do not generate an inflammatory response when aspirated into the lungs of mice.

"This means that there might be a way to render carbon nanotubes harmless, for example in the event of an accident at a production plant," said Fadeel. "But the findings are also relevant to the future use of carbon nanotubes for medical purposes."