Proc. Natl Acad. Sci. USA http://doi.org/x4p (2015)

Credit: NAS

Mechanical machines combine joints and hinges to perform complex motion patterns. DNA machines could in principle perform similar three-dimensional motion, yet the design and assembly of DNA origami structures that undergo reversible conformational changes is at a comparatively primitive stage. Carlos Castro and colleagues now show that mechanical devices capable of precise constrained linear motion at the nanoscale, which has so far been difficult to achieve, can be designed and fabricated by following macroscopic-machine design. By combining stiff double-stranded DNA origami components and flexible single-stranded DNA connections, the researchers made crank-sliders (which couple linear and rotational motion) and combinations of hinges and links that make up mechanical linkages. They also show that by employing DNA strand displacement (typically used to reconfigure DNA origami nanostructures) the linkages can move within minutes between open-frame and compact-bundle configurations. The modular design of kinematic joints made of DNA origami should facilitate the design of programmable complex DNA nanomachines for use in, for example, biosensing or triggered actuation.