Nanocars get their motors running

The nanocars developed at Rice are complex molecules with moving parts that can cross surfaces and be steered by electrical or magnetic fields. Although consisting of only a single molecule, the nanocars roll on wheel-like structures connected to an axle. Ideally, these molecular cars could serve as helper molecules in large, ornate chemical reactions.

Most of the nanocars built at the university are propelled forward when an electrical charge is applied to the roadway, a thin film of gold.

The motor, created by Ben Feringa of the Netherlands' University of Gronigen, is attached to the car. When light strikes the paddlewheel on the motor, it begins to turn in a single direction, which then propels the nanocar forward.

The cars, which took eight years to develop, measure only a few nanometers long and are thinner than human DNA (a nanometer is a billionth of a meter). The smallest measures only 2 nanometers long.

The idea behind the research is to create molecules that will act as tools in the chemical reactions that will be employed to build microprocessors or other electronics components in the future, said James Tour, a professor and the primary researcher behind the nanocars. A nanocar, for example, could be employed to ferry the loose end of a carbon nanotube to a point where it can connect to make a circuit.

Roughly speaking, the nanocars would act like enzymes for industrial applications, he said. Enzymes in living beings help break down food and other substances and transport the by-products to the appropriate molecule for the next step in processing. Hemoglobin, for example, transports oxygen. Although Tour does not envision these molecules being used in medicines or for biological applications, the metaphor works.

"When you eat food in the morning and then it is part of your ear the next day, how did that happen?" Tour said. "Self-assembly alone is not sufficient."