A nanoscale rotor made from DNA could be used as a tiny valve for tasks like sorting molecules or it could act as a switch in a biological computer.
Designing moving mechanical systems at nanoscale is difficult because of the random movements of small molecules, which knocks components back and forth. There are many examples of effective biological motors in nature, such as F-ATPase, an energy-producing enzyme with a central rotating column, but functioning synthetic nanomotors had yet to be built.
at the University of Oxford and his colleagues have developed a rotor made from DNA that can spin with a similar force and speed to F-ATPase.
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鈥淭his machine is the first one of its kind which can deliver this level of torque, of work and of speed,鈥� says Golestanian. 鈥淎ll these numbers are really record breaking at this scale for a synthetic system, and they are very, very close to what biology does.鈥�
The team built the rotor using DNA origami, which involves designing DNA structures with software and then constructing them through a series of chemical reactions. Because the interactions of DNA鈥檚 base pairs are well understood, strong and nimble structures can be made by making the base pairs interact at specific points.
The rotor consists of a pedestal and a dock for the rotor 鈥渂lade鈥�, which is about a thousand times thinner than a human hair. The dock has grooves so that a rigid rod, also made from DNA, preferentially moves in one direction when placed in an electric field. Though the rod is constantly jittering slightly from side to side, it clearly moves in 180 degree turns, which means it can apply force to objects in its path.
鈥淚t is a really fascinating leap forward in trying to synthesise these nanoscale motors based on biological motor principles,鈥� says at the University of Kent, UK.
While the team doesn鈥檛 propose any immediate uses for the rotor, it could have a number of applications. Kad says that the rotor arm could be controlled by the electric field to sort specific molecules, acting as a valve, or could switch back and forth in a binary way, which would make it a potential component of a biological computer.
Nature
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