Mechanochemistry strips cargo molecules from a loaded rotaxane

Researchers have created a nanoscale system that might be used to deliver drugs or release molecules that repair damaged materials ( Nature 2024, DOI: 10.1038/s41586-024-07154-0 ). The system relies on mechanochemistry , in which a mechanical force causes a chemical reaction. In this effort, the researchers rely on long polymer strands tethered to a force-sensitive molecule known as a mechanophore . "The idea is to use polymers as a rope in a tug-of-war," says Guillaume De Bo of the University of Manchester, who led the new work. In solids, an impact can tug the polymer strands apart and trigger the mechanophore's reaction. Researchers have previously used this strategy to release fluorescent molecules to signal damage in a material. In solution, bursts of ultrasound have the same mechanochemical effect. But each tug-of-war bout can free only a single molecule, which limits the concentration of released molecules. De Bo's team has now