Buckyballs and nanotubes are members of a class of carbon-based nanoparticles known as the fullerenes. Buckyballs are spherical in shape while carbon tubes are cylindrical. A single wall carbon tube is a one-atom-thick sheet of graphite, resembling chicken wire, rolled seamlessly into a tube. There are also multi-walled and other types of tubes depending on the shape, diameter, density (hollow versus solid) and other properties.
The diameter of a carbon tube can be several nanometers but the length can be much greater, up to several millimeters, depending on its intended use, creating very long and thin hollow cylinders. Carbon nanotubes have many applications in materials science due to their strength and unique electrical properties. Depending on how the tubes are rolled, they can act as conductors or semiconductors, with conductivity comparible to copper. Among the many other uses for these fullerens is as energy storage units, sensors and radiation sources. Scientists at MIT have reported the discharge of electricity by carbon nanotubes under certain conditions. IBM researchers are working with tiny rings made of long nanotubes thought to be held in their coiled position by van der Waals forces.
The fullerenes have also been found useful in the field of biomedicine. Their electrical properties are conducive to their use as medical imaging devices, and fluorescent carbon nanotubes have been isolated that might be used to detect and kill cancer cells. The fullerenes can also be used as carriers for vaccines, drugs and other molecules, depending on what ligands can be attached to their carbon lattice. Multi-walled carbon nanotubes have been proposed as a method for improving thermal therapy and "cooking" cancerous cells (nanothermal therapy). Because the safety of nanoparticles was still poorly understood as of early 2010, few nanoparticles have been approved by the FDA for medical treatments.