Nano-wheels seen rolling at last

It is the nano-equivalent of seeing the first stone disc roll down a prehistoric hill: German and French scientists have, for the first time, observed a nanoscopic wheel rolling over a flat surface. The researchers created a carbon molecule resembling a pair of wheels just 0.8 nanometres in diameter, joined together by an axle only four carbon atoms long. The achievement was a combined effort by researchers at the Free University of Berlin in Germany and the Center for Material Elaboration & Structural Studies in Toulouse, France. After being chemically synthesised in the lab, hundreds of these "nanowheels" were sprayed onto a sheet of copper. The researchers then used the tip of a scanning tunnelling electron microscope (STEM) to push individual molecules across a copper surface. **Right direction** "Using the STEM provided a direct readout that shows the wheels [only] roll when pushed in the right direction," perpendicular to the axle, says Leonhard Grill, leader of the German research team, told New Scientist. If nudged the wrong way, the molecules instead skip across the surface... Whole article: "http://www.newscientisttech.com":[ http://www.newscientisttech.com/article.ns?id=dn11002]

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