In a one-of-a-kind race, DNA motors have achieved some of the fastest speeds and longest distances ever travelled by nanometre-scale machines.

The track: a standard glass slide covered with RNA. For the motors, Yonggang Ke, Khalid Salaita and their colleagues at Emory University in Atlanta, Georgia, folded a very long strand of DNA back on itself 16 times to create a 3D beam. The researchers attached 36 ‘legs’ — short RNA strands that could bind the RNA on the track — to each of the beam’s 4 long faces.

After the DNA devices were placed on the track, the legs on the bottom face found their footholds within minutes. To start the race, the researchers added an enzyme that breaks apart double-stranded RNA molecules. When the enzyme detached the legs from the track, each beam tipped forward onto its next face, thus rolling in a straight line from its starting point.

In a 99-vehicle race, some of the DNA motors sped down the track at more than 100 nanometres per minute, compared with only 10 nanometres per minute for previously developed DNA machines.