Genetic material as a motor: For the first time, scientists have converted the genetic molecule DNA into a nanoscale electric motor. To do this, they assembled several strands of DNA to form a base with a rotor arm. If voltage is applied now, the DNA rotor begins to move and twist in one direction, as researchers report in the journal “Nature.” The new nano-electric motor opens up the possibility of driving nano-processes and chemical reactions in new ways.
Engines have freed mankind from labor for many centuries. Their main function is to convert various forms of energy into motion, even at very small scales. There are now nanomotors that are only one nanometer in size and others that were created from the DNA genetic material molecule. However, until now, these have only been able to generate motion from chemical energy, not electrical energy.
origami with genetic material molecules
A team led by first author Anna-Kathrina Pum from the Technical University of Munich has now fabricated a nano-sized electric motor out of DNA. To assemble the molecular motor, the scientists used a technique known as DNA origami. With this method of construction, several long single strands of genetic material serve as the parent structure, to which other complementary DNA segments are added. Molecule sequences are selected such that the desired structures arise from tethers and folds.
“We have been working with this method for many years and can now develop very precise and complex objects like molecular switches and hollow bodies that can contain viruses. If you put a strand of DNA with the corresponding sequences into solution, the objects come together on their own,” says lead author Hendrik Dietz from the Technical University of Munich.
Base, Platform, Rotor
The researchers used the origami technique to build the three components of their new DNA engine. They are based on a base about 40 nanometers high, which is attached to a glass plate using polyethylene glycol. A 13 nanometer thick DNA platform is then mounted on the leg, which connects the base to a 500 nanometer long DNA rotor arm. The composition of the intermediate element is responsible for the operation of the engine.
Basically, the DNA engine acts as a sort of ratchet. The intermediate platform has constraints that limit rotation of the rotatably mounted arm. Without a specific energy input, the rotor moves randomly and uncontrollably, as it is only affected by collisions with solvent molecules. However, as soon as an alternating voltage is applied across both electrodes, the arm rotates purposefully and continuously in the desired direction. Finally, scientists can influence the speed and direction of rotation through the direction of the field and the frequency and magnitude of the voltage.
“Technically unparalleled skills”
“The new engine has unrivaled mechanical capabilities,” says co-author Ramin Golestanian of the Max Planck Institute for Dynamics and Self-Organization in Göttingen. “It can reach a torque of the order of 10 piconewtons per nanometer. And it can generate more energy per second than the energy released by splitting two ATP molecules.
The scientists hope that the engine they have developed will be used in the future for specific technical tasks, such as converting electrical energy into chemical energy. “We could potentially use it to cause chemical reactions in the direction of ATP production. For example, surfaces could be densely covered with such engines,” says Dietz. “Then you combine the raw materials, apply a small alternating voltage and the motors produce the desired chemical compound.” (Nature, 2022; doi: 10.1038/s41586-022-04910-y)
Source: Technical University of Munich