DNA: Not Merely the Secret of Life

DNA is well-known as the genetic material of living organisms.  We build branched species that can be connected to one another using sticky ends. Such sticky-ended cohesion is used to produce N-connected objects and lattices.  We have used ligation to construct DNA stick-polyhedra and topological targets, such as Borromean rings. Branched junctions with up to 12 arms have been produced.  We have also built DNA nanotubes with lateral interactions.

Nanorobotics is a key area of application. PX DNA has been used to produce a robust 2-state sequence-dependent device that changes states by varied hybridization topology.  Bipedal walkers, both clocked and autonomous have been built. We have constructed a molecular assembly line by combining a DNA origami layer with three PX-based devices, so that there are eight different states represented by the arrangements of these devices; we have programmed a novel DNA walking device to pass these three stations.  As a consequence of proximity, the devices add a cargo molecule to the walker.  We have demonstrated that all eight products (including the null product) can be built from this system.

A central goal of DNA nanotechnology is the self-assembly of periodic matter. We have constructed 2-dimensional DNA arrays with designed patterns from many different motifs. Recently, we have used DNA scaffolding to organize active DNA components, as well as other materials.  Active DNA components include DNAzymes and DNA nanomechanical devices; both are active when incorporated in 2D DNA lattices.  We have used pairs of PX-based devices to capture a variety of different targets.  Multi-tile DNA arrays have also been used to organize gold nanoparticles in specific arrangements.

Recently, we have self-assembled a 3D crystalline array and have solved its crystal structure to 4 Å resolution, using traditional unbiased crystallographic methods.  Nine other crystals have been designed following the same principles of sticky-ended cohesion.  We can use crystals with two molecules in the crystallographic repeat to control the color of the crystals.  Thus, structural DNA nanotechnology has fulfilled its initial goal of controlling the structure of matter in three dimensions.  A new era in nanoscale control is beginning.

This research has been supported by the NIGMS, NSF, ARO, ONR and the W.M. Keck Foundation.