Nanolattices of switchable DNA-based motors.

Miniaturization is an important aspect of device fabrication. Despite the advancements of modern top-down approaches, scaling-down to the sub-nanometer size is still a challenge. As an alternative, bottom-up approaches, such as the use of DNA as an engineering material, are therefore emerging, allowing control of matter at the single-molecule level. A DNA-based self-assembly method for the construction of switchable DNA devices is descrbied here based on G-quadruplex moieties, which are patterned on quasi-planar DNA arrays with nanoscale precision. The reversible switching of the devices is triggered by addition of DNA sequences ('fuels') and translated into linear extension/contractile movements. The conformational change of the devices was visualized by atomic force microscopy and FRET spectroscopy. Steady state fluorescence spectroscopy indicated that scaffolding of the G4 motors to either individual tiles or extended superlattices had no significant impact on the switching and optical performance of the system. However, time-resolved spectroscopy revealed that ordering in the microstructural environment enhances the fraction of molecules subject to FRET. Altogether, our study confirms that DNA superstructures are well-suited scaffolds for accommodation of mechanically switchable units and thus opens the door to the development of more sophisticated nanomechanical devices.