A DNA ring acting as a thermal ratchet

Abstract

Several DNA nanomotors have been recently constructed in laboratories worldwide. Thesemachines are, however, relatively slow and do not perform continuous rotations. We have recentlyproposed a rotary DNA nanomachine that shows a continuous rotation with a frequency of102–104 Hz. This motor is a closed DNA ring whose elastic features are tuned such that it can beexternally driven via e.g. periodic temperature changes. As a result, the twirling ringpropels itself through the fluid with a speed of tens of nanometres up to a few microns persecond. The current paper gives a more detailed presentation of this motor and provides aderivation of the low- and high-frequency asymptotic behaviour of thermal ratchets ingeneral.