This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Molecular machines are regarded as the next step in miniaturization. Their models can be found in living cells, where molecular motors convert energy and generate movement.
Scientists have been working for decades to artificially replicate such systems. The 2016 Nobel Prize in Chemistry was awarded for this research. Molecular motors powered directly by an electric current have been in existence since 2011.
Until now, however, they have only functioned as molecules on a surface, driven by the tip of a scanning tunneling microscope. For their new machine, the researchers drew inspiration from one of humanity's oldest documented machines: the Archimedes screw, which transports water uphill. The researchers applied the principle of the Archimedes screw at the molecular level.
Instead of water, electrons flow through a helical structure, setting it in rotation. The research is published in the journal Nature. At the heart of the machine is a helical molecule, which was produced specifically for the study by Professor Michael Pittelkow's team at the University of Copenhagen.
The molecule, which measures just a few millionths of a millimeter, can be bound to gold surfaces via sulfur atoms. At the Weizmann Institute of Science in Israel, the team led by Professor Oren Tal and Dr. Anil Kumar Singh stretched individual molecules between two atomically fine gold tips.
By precisely adjusting the distance between the electrodes, the researchers were able to stretch or compress the molecular screw. Measurements then showed that the molecule rotates when a voltage is applied. The direction of rotation was unambiguous and could be reversed by changing the polarity of the voltage.
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