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Sensors based on single-walled carbon nanotube (SWNTs) could be 'reset' at the simple flick of a switch, say researchers in the US. The team found that organic molecules bound to the nanotube surface are shaken off when an electric current is passed through the material, resetting the sensor ready for further use.SWNTs can be used in very small, highly sensitive chemical sensors for a variety of gases and other chemicals. The SWNTs, attached to a silicon substrate, absorb chemicals onto their surface, however many chemicals are irreversibly absorbed resulting in lengthy processes before the sensor can be reused.Richard Masel and colleagues at...

In a remarkable home movie, an international team of researchers has filmed individual metal atoms as they move around and react within the confines of a carbon nanotube. As well as demonstrating the power of the imaging technique, the work has shown that the interior of carbon nanotubes may not be as inert as previously assumed.Andrey Chuvilin from the University of Ulm in Germany and colleagues trapped single atoms of the heavy metal dysprosium within hollow fullerene spheres made up of 82 carbon atoms, and enclosed a series of these dysprosium-seeded cages within single-walled carbon nanotubes, with the fullerenes stringing themselves along the...

DNA could be the answer to sorting different kinds of carbon nanotubes, say US researchers. Short strings of synthetic DNA wind onto nanotubes in a very sequence-dependent way, which has allowed researchers to separate 12 of the most common types of tubes from the inevitable mixtures that form when nanotubes are synthesised. Since the physical and electronic properties of nanotubes are heavily dependent on the size and structure of the tube, separating the mixtures could lead to much more effective nanotube-based devices and even ways of making specific types of tubes selectively.Ming Zheng of Dupont Central R&D, Delaware, and Anand Jagota from...