Researchers at the Technical University of Munich (TUM) have developed the world’s first electric nanomotors made of DNA. The self-assembling structures can be activated by an electric charge to spin a ratcheting rotor arm.
The tiny motor was made using a technique called DNA origami. Like its namesake papercraft, the method involves intricately folding strands of DNA into three-dimensional shapes, with past examples including virus traps, immune-evading drug delivery systems, and even microscopic Van Gogh replicas. These structures are made by carefully selecting DNA sequences that will fold and attach to each other in certain ways, so researchers can add specific strands to a solution and let the DNA objects assemble themselves.
For the new study, the team used this process to make a molecular motor out of DNA for the first time. The motor consists of a rotor arm measuring up to 500 nanometers (nm) long, which is mounted on a base about 40 nm high that’s fixed to a glass plate. Wrapped around the tip of the base, just below the rotor, is a platform with several ratcheting obstacles built into its surface, which controls the direction that the rotor can spin.
To turn the nanomotor on, an AC voltage is applied from two electrodes, which causes the rotor to spin. The team can control the speed and direction of that rotation by changing the direction of the electric field, and adjusting the frequency and amplitude of the applied voltage.
While this is the first nanomotor to be made from DNA, other similar designs have been built in the past. Simple ones can be just gold nanorods that spin in response to ultrasound, while others are made up of as little as 16 atoms. These previous designs had potential to be used to propel tiny robots, but the team says the new DNA nanomotor could be put to work doing chemistry.
“If we develop the motor further we could possibly use it in the future to drive user-defined chemical reactions,” said Hendrik Dietz, lead author of the study. “Then, for example, surfaces could be densely coated with such motors. Then you would add starting materials, apply a little AC voltage and the motors produce the desired chemical compound.”
The research was published in the journal Nature.
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