UK – Tiny, molecular machines work in many biological processes such as the metabolism in the cells. Artificial motors from single molecules have the potential to be used in future as Nanomotors in tiny technical, chemical or medical procedures. On the still long way to produce artificial Nanomotors and especially being able to control them, now a British group has taken an important step towards it. They developed a molecule motor driven as an internal combustion engine of a single chemical. This study has been published in the journal Nature.

David Leigh of the University of Manchester said that previously developed molecular motors required the addition of more reagents and some chemical intermediate steps. The new Nano engine, which he developed together with his colleagues, only needs a single chemical as fuel. These existed in sufficient quantity; a continuous rotary motion began in a clockwise direction. This movement stopped as soon as the fuel substance was consumed.

The built engine is made from a ring-shaped macromolecule called Catenan. To this ring, also ring-shaped motor molecule, made from benzyl amide could move in this ring. To obtain a targeted rotation of the benzyl amide ring Catenan ring, regular docking and removing the fuel chemical, 9-Fluorenylmethoxycarbonyl (Fmoc), was necessary. These Fmoc molecules reacted with the Catenan ring. The reaction energy was released, which led to the movement of the benzyl amide ring in a clockwise direction. Repeated docking and removing the Fmoc molecules allowed a slow rotation of the benzyl amide ring. Once the fuel that existed as Fmoc chloride runs out, it stopped the rotation movement.

In this basic experiment, a full 360 ° cycle took about twelve hours. Thus, though the movement could be controlled it is too much slow for a meaningful application as Nanomotor. In regards to this limitation, Leigh said that even the very first car by Carl Benz in 1885 just drove in walking pace. So he hopes to accelerate the nanomotors by varying other parameters such as temperature or Fmoc concentration.