Electrical Actuation of DNA-Based Nanomechanical Systems.

DNA nanotechnology provides efficient methods for the sequence-programmable construction of mechanical devices with nanoscale dimensions. The resulting nanomachines could serve as tools for the manipulation of macromolecules with similar functionalities as mechanical tools and machinery in the macroscopic world. In order to drive and control these machines and to perform specific tasks, a fast, reliable, and repeatable actuation mechanism is required that can work against external loads. Here we describe a highly effective method for actuating DNA structures using externally applied electric fields. To this end, electric fields are generated with controllable direction and amplitude inside a miniature electrophoresis device integrated with an epifluorescence microscope. With this setup, DNA-based nanoelectromechanical devices can be precisely controlled. As an example, we demonstrate how a DNA-based nanorobotic system can be used to dynamically position molecules on a molecular platform with high speeds and accuracy. The microscopy setup also described here allows simultaneous monitoring of a large number of nanorobotic arms in real time and at the single nanomachine level.