A Scottish whisky still, slowly corroded by copper and sulfur, inspired a discovery that could revolutionize microscopic engineering. Researchers at the University of Strathclyde have harnessed the very chemistry that consumes whisky-making equipment to create tiny self-propelled particles that swim through liquid on their own—opening a path toward machines so small that several could fit across the width of a human hair.
The breakthrough matters because self-propelled microscopic systems have long been a goal of materials science, with potential applications ranging from targeted drug delivery to environmental sensing. Until now, creating reliable "swimmers" at the nanoscale has required complex synthetic designs. By looking to nature and industry, the Strathclyde team found an elegant solution hidden in plain sight: the same sulfur compounds that give whisky its distinctive flavors and aromas could power microscopic movement.
Dr. Juliane Simmchen, lead researcher in the University of Strathclyde's Department of Pure & Applied Chemistry, explains the insight with clarity. "The work was inspired by the well-known reactivity between copper and sulfides that slowly consumes the whiskey stills and requires them to be exchanged periodically during whiskey making," she says. The team realized that if copper and sulfur compounds could corrode industrial equipment, they could also fuel motion at the microscopic scale. The tiny swimmers are copper-based particles. When placed in liquids containing certain sulfur compounds—particularly water-soluble ones linked to whiskey production—reactions on the particle surface propel them forward independently.
The results are striking. Some particles reached speeds of up to 30 micrometers per second, a respectable velocity in the microscopic world. The researchers also tested their swimmers in mixtures of water and ethanol—the alcohol found in whiskey itself—and discovered that changing the liquid environment altered how the particles moved. This finding hints at a crucial capability: the ability to control microscopic propulsion systems through their chemical environment, a prerequisite for any practical application.
What makes this work particularly elegant is its simplicity. Rather than engineering exotic materials from scratch, the scientists drew inspiration from the chemistry of whisky production, a centuries-old industrial process refined through generations of craftspeople. The sulfur compounds they used aren't laboratory rarities—they're byproducts of a well-understood and widely practiced craft. This connection to everyday industrial chemistry could make the approach more scalable and accessible than solutions requiring rare or synthetic components.
The findings, published in ACS Applied Materials & Interfaces by Khalifa Mohamed and colleagues, represent more than just a clever proof of concept. They demonstrate how nature and traditional industry can seed innovation in cutting-edge science. The next phase will likely explore how to refine control of these particles, scale production, and adapt the approach to specific applications—whether delivering medicine to targeted sites in the body or creating sensors that can move independently through fluids.
For now, the work stands as a reminder that sometimes the most promising path forward looks back—to whisky stills and sulfur chemistry, to the observable world, and to the idea that great innovations often hide in processes we've already mastered.