DNA: Not Merely the Secret of Life -
Using the Information in DNA to Control Molecular Structure
Our laboratory is investigating unusual DNA molecules in model systems that use synthetic molecules.
A major effort in our laboratory is devoted to DNA nanotechnology.
The attachment of specific sticky ends to a DNA branched junction enables the construction of stick figures, whose edges are double-stranded DNA.
This approach has already been used to assemble a cube, a truncated octahedron, nanomechanical devices and 2D crystals and 3D crystals from DNA.
Ultimate goals for this approach include the assembly of a biochip computer, nanorobotics and nanofabrication and the exploitation of the rational synthesis of periodic matter.
Thus, we build branched DNA species that can be joined using Watson-Crick base pairing to produce N-connected objects and lattices. We have used ligation to construct DNA topological targets, such as knots, polyhedral catenanes, Borromean rings and a Solomon's knot. Branched junctions with up to 12 arms have been made.
Nanorobotics is a key area of application. We have made robust 2-state and 3-state sequence-dependent devices and bipedal walkers. We have constructed a molecular assembly line using a DNA origami layer and three 2-state devices, so that there are eight different states represented by their arrangements. We have demonstrated that all eight products can be built from this system.
A central goal of DNA nanotechnology is the self-assembly of periodic matter. We have constructed 2D DNA arrays with designed patterns from many different motifs. We have used DNA scaffolding to organize active DNA components. We have used pairs of 2-state devices to capture a variety of different DNA targets.
One of the key aims of DNA-based materials research is to construct complex material patterns that can be reproduced. We have built such a system from bent TX molecules, which can reach 2 generations of replication. This system represents a first step in self-reproducing materials. We are making progress towards selection of self-replicating materials.
Recently, we have self-assembled a 3D crystalline array and have solved its crystal structure to 3 Å resolution, using unbiased crystallographic methods. 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 DNA in three dimensions. A new era in nanoscale control and molecular programming awaits us.
This research has been supported by the NIGMS, NSF, ARO, ONR, DOE and the Gordon and Betty Moore Foundation.
Ned Seeman is most noted for his development of the concept of DNA nanotechnology, beginning in the early 1980s.
Seeman's laboratory published the synthesis of the first three-dimensional nanoscale object, a cube made of DNA, in 1991. This work won the 1995 Feynman Prize in Nanotechnology.
The concepts of DNA nanotechnology later found further applications in DNA computing, DNA nanorobotics, and self-assembly of nanoelectronics. He shared the Kavli Prize in Nanoscience 2010 with Donald Eigler for their development of unprecedented methods to control matter on the nanoscale. The goal of demonstrating designed three-dimensional DNA crystals was
achieved by Seeman in 2009, nearly thirty years after his original elucidation of the idea.