Scientists recently tied the smallest, tightest knot ever recorded, with just 54 atoms. The microscopic twist is in the form of a trefoil, the simplest type of nontrivial knot, with three interlaced crossings and no loose ends. The newly formed ‘metallaknot’ contains gold and even assembles itself. Scientists discovered this unintentionally. The researchers were originally trying to connect carbon structures to gold acetylides, a class of chemical compounds. During this process, one of the reactions yielded a golden chain that tied itself into a tangle resembling a three-leaf clover.
Along with being exceedingly tiny, the knot was also the tightest ever tied. Knot tightness is measured by its backbone-to-crossing ratio (BCR), with the smallest value representing the tightest knot. The previous record holder for tightest knot had a BCR of 24, but this new trefoil just edges it out with a BCR of 23.
Knot structures are crucial for binding together DNA, RNA and proteins that the human body depends on. Unravelling the mysteries of knots could also have real-world applications, from building more effective plastics to creating new types of chemotherapies.