Reverse the voltage and it spins the other way: a motor the size of one molecule
What happened
An international team has built a working motor out of a single molecule, and found something they did not expect: when it spins, it conducts electricity about a hundred times better. The design borrows from Archimedes. An Archimedes screw is an old piece of engineering - a spiral inside a tube that lifts water when you turn it. The molecule at the heart of this experiment is a spiral, and it behaves in a comparable way at a scale almost impossible to picture. It measures a few millionths of a millimetre and attaches to gold surfaces through sulfur atoms. To run it, researchers held the molecule between two gold tips sharpened down to atomic dimensions, then applied a voltage. The molecule rotated. Reverse the polarity of the voltage, and the rotation reverses with it. Push past a certain voltage threshold and the movement stops being occasional twitching and becomes continuous rotation. The surprise was in the conductivity. During rotation, the molecule's ability to carry current rose by up to two orders of magnitude - a hundredfold increase. Quantum mechanical simulations explained why. Some orientations of the molecule conduct electricity much better than others, and those happen to be positions the molecule tends to avoid when it is sitting still. Rotation forces it through them. As Léon Martin, a PhD student at the University of Augsburg, put it: 'It is only the rotation that makes these positions accessible.' The work was shared out across several groups. Professor Michael Pittelkow at the University of Copenhagen created the spiral molecule. Professor Oren Tal and Dr Anil Kumar Singh at the Weizmann Institute of Science in Israel positioned the molecules between the gold electrodes and took the measurements. Professor Fabian Pauly and his PhD students at the University of Augsburg ran the simulations on a supercomputer called LiCCA. Professor Per Hedegård in Copenhagen and Professor Jing-Tao Lü in Wuhan contributed to the theoretical modelling. The paper, 'Current-Driven Molecular Machine with Rotation-Enhanced Conductance', was published in Nature. The news release appeared on 1 November 2026.
Why this matters
Everything that moves inside a living cell is driven by molecular machines. Muscles contract because of them. Bacteria swim using a rotating motor built of proteins. Nature has been doing this for billions of years. Building one from scratch, out of a designed molecule, and driving it with nothing but an electric current, is a different proposition. It means a machine that small can be controlled directly - switched on, switched off, and reversed - without chemistry, light or heat. Professor Fabian Pauly summarised the achievement carefully: 'We have shown that an electric current can be used to generate a directed rotation.' Directed is the key word. Random jiggling is easy at this scale; everything jiggles. Getting consistent motion in a chosen direction is the hard part. The conductivity finding is the more unusual result, and in a sense it is a bonus. The researchers set out to make something rotate and discovered that the act of rotating changed how well it carried current. That means the molecule's movement and its electrical behaviour are linked - which is interesting both as physics and as a possible way of reading what a single molecule is doing. That last point is quietly useful. Yuta Ito, another PhD student on the team, noted the practical difficulty: 'In the experiment, you only see the current.' You cannot watch a molecule spin. You can only measure electricity and infer the motion. If rotation reliably changes conductance, then the current becomes a window onto the movement.
What the evidence actually says
This is fundamental research, published in a highly selective journal, and it is a long way from anything you could buy. What has been demonstrated: a single molecule, held between two atomically sharp gold tips in a laboratory, rotates when voltage is applied, reverses when polarity reverses, rotates continuously above a voltage threshold, and conducts up to a hundred times better while doing so. Simulations reproduce the behaviour and explain the mechanism, and a simplified theoretical model reproduces both the rotation and the current increase. What has not been demonstrated is anything resembling a device. There is no array of these motors doing useful work, no integration into a circuit, no operation outside the specialised apparatus required to hold a single molecule in place. The conditions are the point of the experiment and also its limitation. The applications listed in the release should be read as possibilities rather than plans: molecular electronic components, spintronics - which uses properties of electrons beyond their charge - microfluidic systems handling tiny fluid volumes, and a new way of studying physical processes at the atomic scale. That last one is the nearest to hand, because it is a research tool rather than a product. It is worth appreciating how much had to come together. A chemist in Copenhagen designed and made the molecule. Experimentalists in Israel built an apparatus capable of holding one molecule between electrodes and measuring it. Theorists in Germany, Denmark and China worked out what the measurements meant, using a supercomputer. No single group could have done this, which is why the author list runs to thirteen people across four countries. The funding, for anyone interested in how this work gets paid for: the German Research Foundation through a Collaborative Research Centre, the LiCCA supercomputer, and - for the collaborating institutions - the European Research Council, the Israel Science Foundation and several others. This is publicly funded curiosity-driven science, which is how most of the useful things eventually arrive.
Practical advice
Nothing to act on, so here is what this story is good for. **Use it as a reason subjects connect.** This one experiment needed synthetic chemistry, quantum physics, electrical measurement, high-performance computing and mathematics. If a young person is asking why they have to do all of these at once, this is a clean answer. **Learn the difference between fundamental and applied research.** This is fundamental: done to find out whether something is possible. Applied research starts from a problem someone wants solved. Both matter, and conflating them is how 'scientists build tiny motor' turns into unfounded expectations about nanobots. **Be sceptical of application lists.** When a press release lists possible uses, those are informed guesses by the authors, not a roadmap. Treat them as 'this might one day be relevant to' rather than 'this will be used for'. **Note the role of simulation.** Much of the understanding here came from computer modelling of quantum behaviour, not just from the measurement. Modern physics is often experiment and simulation working together, with neither sufficient alone. **If the Archimedes screw is new to you, look it up.** It is a genuinely elegant bit of ancient engineering, still used today for moving water and in some wastewater plants. The fact that the same geometry works at the scale of a molecule is the sort of thing that makes physics worth paying attention to. **The paper has a DOI.** If you want the real thing rather than a summary, the reference is in the sources below.
What to know
Researchers have built a motor from a single spiral-shaped molecule, based on the Archimedes screw principle, and driven it using nothing but an electric current. Applying voltage makes it rotate; reversing the polarity reverses the direction; above a threshold voltage the rotation becomes continuous. The unexpected finding was that rotating made the molecule conduct electricity up to a hundred times better. Simulations showed why: the best-conducting orientations are ones the molecule avoids when at rest, and rotation forces it through them. The molecule, a few millionths of a millimetre across, was held between gold tips sharpened to atomic dimensions. The paper, 'Current-Driven Molecular Machine with Rotation-Enhanced Conductance', was published in Nature by a thirteen-author team spanning the University of Copenhagen, the Weizmann Institute of Science, the University of Augsburg and institutions in Denmark and China. This is fundamental research with no device at the end of it yet. Possible future uses named by the authors - molecular electronics, spintronics, microfluidics and atomic-scale measurement - are informed possibilities rather than plans. The nearest-term use is as a research tool, because rotation changing conductance means an electrical reading can reveal what a single molecule is doing. It is a good illustration of how modern science works: chemistry, experimental physics, theory and supercomputing across four countries, publicly funded, driven by curiosity rather than a product. Sources: ScienceDaily (University of Augsburg news release), 'Scientists Shrink Archimedes Screw to the Size of a Single Molecule', 1 November 2026, https://www.sciencedaily.com/releases/2026/10/261030002940.htm; Singh AK, Martin L, Sršen M and others, 'Current-Driven Molecular Machine with Rotation-Enhanced Conductance', Nature, 2026, https://doi.org/10.1038/s41586-026-11312-x; University of Augsburg, https://www.uni-augsburg.de/en/ This article is for general information about published scientific research. It contains no health or medical guidance; for any health concern, speak to a doctor, pharmacist or other qualified healthcare professional.
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