DNA nanostructures are made using synthetic DNA strands, the sequences of which are designed such that they will self-assemble into the desired form by hybridization of complementary domains. Various structures and devices have been presented, including DNA tweezers, nanorobots and a range of linear motors such as bipedal walkers. Inspiration for the latter is drawn from naturally occurring molecular motors like kinesin. This paper describes a concept for an autonomous rotary nanomotor made from DNA, which utilizes the well-known and widely-studied phenomenon of toehold-mediated DNA strand displacement. The motor is to be driven by a series of strand displacement reactions, the order of which is controlled by steric constraints arising from the secondary structure of the DNA strands comprising the motor mechanism. The capabilities of DNA motors would be extended significantly if autonomous rotary motion could be achieved. The device has a range of potential applications, including molecular computation and single-molecule manipulation.
