Designs of Autonomous Unidirectional Walking DNA Devices

Imagine a host of nanoscale DNA robots move autonomously over a microscale DNA nanostructure, each following a programmable route and serving as a nanoparticle and/or an information carrier. The accomplishment of this goal has many applications in nanorobotics, nano-fabrication, nano-electronics, nano-diagnostics/therapeutics, and nano-computing. Recent success in constructing large scale DNA nanostructures in a programmable way provides the structural basis to meet the above challenge. The missing link is a DNA walker that can autonomously move along a route programmably embedded in the underlying nanostructure – existing synthetic DNA mechanical devices only exhibit localized non-extensible motions such as bi-directional rotation, open/close, and contraction/extension, mediated by external environmental changes. We describe in this paper two designs of autonomous DNA walking devices in which a walker moves along a linear track unidirectionally. The track of each device consists of a periodic linear array of anchorage sites. A walker sequentially steps over the anchorages in an autonomous unidirectional way. Each walking device makes use of alternating actions of restriction enzymes and ligase to achieve unidirectional translational motion.