Ned Seeman
New York University
Structural DNA nanotechnology uses reciprocal exchange between DNA double helices to produce branched DNA motifs. Using sticky-ended cohesion, these branched motifs can be combined to produce specific structures.
We have used this approach to make DNA stick-polyhedra, topological targets, such as knots and Borromean rings, and a variety of 2D DNA crystalline arrays. We have employed robust motifs designed to associate in a 2D pattern to organize metallic nanoparticles. Recently, we have extended 2D self-assembly to three dimensions with 4 Å resolution; the crystal structure of this 3D arrangement has been determined and confirms the rhombohedral structure that was designed.
We have also constructed a number of sequence-dependent nanomechanical devices, such as a bipedal walker and a machine that translates DNA sequences into polymer assembly instructions. The walker traverses a sidewalk in either direction as a consequence of the addition and removal of specific strands. The translation machine is based on a device that rotates one end relative to another by a half-turn; this device is also driven in a sequence-specific fashion by the addition and removal of specific strands. We have incorporated this device into a cassette that includes a domain to insert it into a 2D periodic array, along with a robotic arm that is reoriented by the motion of the device. By using atomic force microscopy, we are able to demonstrate that the device is active when it is inserted into the array, thereby laying the basis for a DNA-based nanorobotics. Sticky ends that face each other on a pair of these devices can be used to capture a variety of DNA motifs; an error-correction protocol has been developed for this procedure.
Friday, February 13 at 4:00 PM
Room L211, Technological Institute
Refreshments are served at 3:30 PM
