Motor molecules made into muscles

Abstract

Chemists have gotten a lot of mileage out of the Nobel Prize-winning, light-activated motor molecules invented in Ben L. Feringa’s lab at the University of Groningen. Feringa has used them to create molecule-sized cars that scoot along a surface, and others have incorporated them into polymers or used them to drill holes in cancer cells (see page 24). Feringa’s group has now managed to get these molecule-sized machines to flex some muscle. His team created a water-soluble version of the motor that assembles into fibers. In the presence of calcium ions, these fibers organize into macroscale strings made mostly of water that flex in response to ultraviolet light. They can even lift a small weight: a 400-mg piece of paper (Nat. Chem. 2017, DOI: 10.1038/nchem.2887). As with previous versions of Feringa’s motors, these molecules rotate via isomerization around a double bond when hit with UV light. The motor molecules pack