High-speed DNA-based rolling motors powered by

DNA-based machines that walk by converting chemical energy into controlled motion could be of use in applications such as next-generation sensors, drug-delivery platforms and biological computing. Despite their exquisite programmability, DNA-based walkers are challenging to work with because of their low fidelity and slow rates (∼1 nm min–1). Here we report DNA-based machines that roll rather than walk, and consequently have a maximum speed and processivity that is three orders of magnitude greater than the maximum for conventional DNA motors. The motors are made from DNA-coated spherical particles that hybridize to a surface modified with complementary RNA; the motion is achieved through the addition of RNase H, which selectively hydrolyses the hybridized RNA. The spherical motors can move in a self-avoiding manner, and anisotropic particles, such as dimerized or rod-shaped particles, can travel linearly without a track or external force. We also show that the motors can be used to detect single nucleotide polymorphism by measuring particle displacement using a smartphone camera. Inspired by biological motors, a number of synthetic motors havebeen developed as model systems that employ a wide range ofchemical reactions1–6. DNA-based machines that walk along a track have shown the greatest promise in recapitulating the proper-ties of biological motor proteins1,7–14. However, the maximum dis-tance travelled by the most-processive DNA-based motors is 1 µm (refs 8,9,12). The velocity of these walkers is also limited to rate