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Nanoscale Car Built with Four-Wheel Drive

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Click to enlarge. Credit: Randy Wind/Martin Roelfs (illustration); Kudernac, Ruangsupapichat et al. in Nature, Vol. 479, pages 208–211 (STM image inset)

Small cars are in vogue, thanks to rising fuel costs and environmental concerns. But the Fiats and Smart Cars of the world have nothing on the new four-wheeler developed by European researchers.

Netherlands-based researchers Tibor Kudernac of Twente University and Nopporn Ruangsupapichat of the University of Groningen and their colleagues have engineered a single molecule with four electric “wheels,” depicted here in an artist’s conception. By applying less than a volt with the tip of a scanning tunneling microscope (STM), the researchers could spin the four wheels and scoot the molecular vehicle six nanometers across a metallic surface in a more or less straight line. (An STM image of the nanovehicle appears in the inset.) The researchers announced their achievement in the November 10 issue of Nature. (Scientific American is part of Nature Publishing Group.)

Molecular vehicles have been constructed before, but past designs have been passive rollers, the researchers report. The new molecule, in contrast, drives by a kind of paddlewheel motion as electrons from the STM tip excite the four wheels, inducing a cycle of structural changes that results in rotary motion. But each wheel turns in one direction only, so forward motion is possible only if all four wheels are oriented in the right way. With other wheel orientations the molecule moves randomly or not at all, Kudernac, Ruangsupapichat and their colleagues found. They predict that their work could form the basis of more complex nanotech systems that require movement on demand.

About the Author: John Matson is an associate editor at Scientific American focusing on space, physics and mathematics. Follow on Twitter @jmtsn.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. Oemissions 9:17 pm 11/9/2011

    we need innovative public transit not more powerful small cars

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  2. 2. jwreed 4:43 pm 11/11/2011

    Need to open ones mind, true progress comes from pure research, this is pure science, innovative public transit has already been resolved at the level of pure science the proplems we are dealing with in public transit are engineering and political. Pure science has the capability of solving thousands of problems at a time, this is the effect that makes pure science so valuable. If we put on blinders and focus on one problem then we end up with one or two very bad solutions to what is essentially a political problem to begin with. So the mantra is to open ones mind beyond the single solution and to allow for free and open research to forge a path into the unknown, trusting that one of the thousands of solutions to pure research will lead you to the solution of the engineering problem that you feel is important.

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