DNA has been used to construct a wide variety of nanoscale molecular devices. Inspiration for such synthetic molecular machines is frequently drawn from protein motors, which are naturally occurring and ubiquitous. However, despite the fact that rotary motors such as ATP synthase and the bacterial flagellar motor play extremely important roles in nature, very few rotary devices have been constructed using DNA. This paper describes an experimental study of the putative mechanism of a rotary DNA nanomotor, which is based on strand displacement, the phenomenon that powers many synthetic linear DNA motors. Unlike other examples of rotary DNA machines, the device described here is designed to be capable of autonomous operation after it is triggered. The experimental results are consistent with operation of the motor as expected, and future work on an enhanced motor design may allow rotation to be observed at the single-molecule level. The rotary motor concept presented here has potential applications in molecular processing, DNA computing, biosensing and photonics.
Sequential strand displacement in a linear construct.
QCM-D data in .csv format. File contains overtone-normalized frequency changes for thirteenth overtone as a function of time, with the corresponding dissipation changes.
Linear.csv
Strand displacement in a folded nanostructure (triangle)
QCM-D data in .csv format. File contains overtone-normalized frequency changes for thirteenth overtone as a function of time, with the corresponding dissipation changes. Data is provided for three cases: 1. triangle folded on surface and supplied with unfolded reverse complement of triangle. 2. pre-folded triangle supplied with unfolded reverse complement of triangle. 3. pre-folded triangle supplied with folded reverse complement of triangle.
Triangle.csv
The rotary motor and its components.
QCM-D data in .csv format. File contains overtone-normalized frequency changes for thirteenth overtone as a function of time, with the corresponding dissipation changes.Data corresponds to four experiments: 1. folded square A supplied with unfolded square B. 2. folded blocked square A supplied with unblocking strand and then unfolded square B. 3. folded square A supplied with folded square B. 4. full motor supplied sequentially with both unblocking strands.
Motor.csv
Assembly of motor components
Agarose gel showing assembly of a surface connector, two folded squares and an unfolded square.
RotaryMotorAssemblySquaresGel.jpg
Polyacrylamide gel presented in Fig 4(d) of paper
Polyacrylamide gel, showing the most important bands. From left to right: unfolded square of type B, folded squares of both types (B then A) and assembled motor - ‘before’ and ‘after’ operation.
PAGE_Fig4d.tif
AFM images acquired in response to reviewer comments
AFM images of individual folded squares and assembled motors. The structures were extraordinarily difficult to image due to their small size. Consequently they adhered poorly to the substrate and were not well-resolved.
AFM.zip