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

DNA origami is a technique in which a long strand of DNA is folded into a predetermined shape with the help of a number of shorter 'staple' strands. The approach has been used to create a range of intricate two- and three-dimensional structures, but these are typically static or, if they can move, offer limited operations. Carlos Castro and colleagues at the Ohio State University have now built origami structures capable of programmable two- and three-dimensional motion by transferring macroscopic machine designs to the nanoscale.

The researchers used a combination of stiff double-stranded DNA components and flexible single-stranded components to first create origami joints capable of simple angular (a hinge) and linear (a slider) motion. These joints could then be integrated to form devices capable of more complex motion such as a crank–slider, which uses three hinges and one slider joint, and a Bennett linkage, which uses four hinges and can transition between a compact bundle and an open frame. Castro and colleagues also show that the Bennett linkage can be made to undergo reversible conformational changes using DNA input strands.