Researchers from Oak Ridge National Laboratory and the
The scientists found that no pulmonary toxicity issues were reported in single-walled carbon nanohorns, which reportedly contradicts numerous studies in rats involving single-walled carbon nanotubes, which have different shapes and sizes compared to nanohorns.
‘We think the difference could be due to the lack of metal contaminants in single-walled carbon nanohorns as compared to single-walled carbon nanotubes, although many factors could be the cause as well,’ Brynn Voy, one of the researchers at ORNL’s Biosciences Division.
Nanohorns are short, horn-shaped tubular structures capped with a conical tip. Individual nanohorns tend to cluster and form a star-like structure between 50 nanometres and 100 nanometres in diameter with the tips of individual nanohorns projecting outward from the centre in all directions.
Since nanohorns can be produced through simple laser ablation of a pure carbon target with the use of transition metal catalysts, the problem of metal contaminants is eliminated. The researchers believe that metal contaminants could be the cause of inflammatory responses and oxidative stress reported in inhalation studies using carbon nanotubes.
The scientists did note, however, that the two forms of nanostructures could elicit very different biological responses.
Other possible applications suggested by the researchers included hydrogen storage in energy and fuel cell applications.