Submicroscopic Molecular Robot Can Be Programmed

Scientists have developed a programmable "molecular robot”--a submicroscopic molecular machine comprised of synthetic DNA that travels between track locations separated by six nm. The robot, a short strand of DNA, follows instructions programmed into a set of fuel molecules determining its destination, for example, to turn left or right at a junction in the track.

The report of the advance, which represents a step toward developing futuristic nanomachines and nanofactories, was published in the March 9, 2011, issue of American Chemical Society's (ACS) journal Nano Letters. Andrew Turberfield, a professor of physics based at the University of Oxford (UK) and colleagues pointed out that other scientists have developed similar DNA-based robots, which move independently. Some of these employ a biped design and move by alternately attaching and detaching themselves from anchor points along the DNA track, foot over foot, when fuel is added. Scientists would like to program DNA robots to autonomously walk in different directions to move in a programmable pattern, a key to channeling their potential as cargo-carrying molecular machines.

The investigators described an advance toward this aim--a robot that can be programmed to choose among different branches of a molecular track, instead of just move in a straight line. The key to this specialized movement is a so-called "fuel hairpin,” a molecule that serves as both a chemical energy source for moving the robot along the track and as a routing instruction. The instructions tell the robot which point is should move to next, allowing the selection between the left or right branches of a junction in the track, precisely controlling the route of the robot, which could potentially allow the transport of pharmaceuticals or other materials.

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