London, April 11 : Scientists in Barcelona have used nanotechnology to develop for the first time a micro vehicle made out of a single molecule, that traveled about 500 millionths of a millimeter along a microscopic rail.

According to a report in Nature News, Adrian Bachtold of the National Centre of Microelectronics in Spain, and his colleagues, have devised this molecular monorail.

The tiny shuttle is made essentially from a single molecule that can be reliably and controllably conveyed along a track in a particular direction, the report added.

The achievement is the latest step in efforts to make mechanical devices at the scale of nanometres (millionths of a millimetre) - one of the key objectives of nanotechnology.

Nanoscale motors and shuttles that move across surfaces and through space in precisely defined ways might serve as the workhorses of a diminutive mechanical engineering, for example by transporting materials to exact locations to make intricate new structures and materials.

Nanotechnological engineers were inspired to develop this kind of micro scale transport by living cells, which achieve their indispensable and impressive molecular organization.

For example, protein-based molecular motors ferry packages along tracks in the cell's scaffolding.

Though engineers have harnessed biological molecular machinery to move nanoscale objects along tiny grooves and channels on a surface, Bachtold's team has pursued a different strategy based on relatively gigantic molecules called carbon nanotubes.

These tubes are artificially created hollow cylinders of pure carbon in which the atoms are joined in sheets similar to those that stack atop one another in graphite.

In carbon nanotubes, the sheets are curled into tubes just a few nanometres wide. They have been hailed as potential building blocks for nanotechnology and have been used as nanoscale pipettes and rails for moving and guiding tiny quantities of material.

This is the first time, however, that nanotubes have been used as both the track and the shuttle.

A short segment of a nanotube fitted onto a thinner one, like a sleeve bearing, can slide around or along the other nanotube with very little friction.

Bachtold and colleagues figured that they might also be able to use such a structure to move cargo attached to the sleeve along the track supplied by the inner tube.

"Our goal was to make a transporter," said Bachtold. "Our very long-term dream is to make nanoscale robots. But, we are really just at the beginning," he added.

ANI