A team of New York University researchers has taken a major step in building a more robust, controllable machine from DNA, the genetic material of all living organisms. Constructed from synthetic DNA molecules, the device improves upon previously developed nano-scale DNA devices because it allows for better-controlled movement within larger DNA constructs. The researchers say that the new device may help build the foundation for the development of sophisticated machines at a molecular scale, ultimately evolving to the development of nano-robots that might some day build new molecules, computer circuits or fight infectious diseases.
The research team was led by NYU chemistry professor Nadrian C. Seeman. Their findings are reported in the January 3, 2002 issue of Nature. Professor Seeman said, "DNA devices can provide models for the development of nanorobotic applications -- provided the individual devices can be manipulated separately. Our findings have taken the first definitive step in localizing movement within molecular scale DNA machines, introducing independence of movement within a wider structure."
Professor Seeman has led research teams to previous breakthroughs in the construction of structures and devices from DNA molecules. All of these structures use base pairing, which allows strands of DNA to be programmed to self-assemble in well-defined ways. In January 1999, Professor Seeman's lab announced the development of a machine constructed from DNA molecules, which had two rigid arms that could be rotated from fixed positions by adding a chemical to the solution. However, the chemical affected all molecules within a structure uniformly.
The research team's most recent findings demonstrate how movement can be manipulated within molecule pairs without affecting others within a larger structure. This is done by inserting DNA set and fuel strands into individual molecule pairs. Scientists used paranemic crossover (PX) molecule pairs and produced a half-turn rotation by converting them into JX2 molecule pairs by removing the set strands with fuel strands and replacing them with new set strands that reconfigure the structure of the device. The data presented include both bulk measurements shown by gel electrophoresis and detection of individual structure changes by atomic force microscopy.
These findings are reported in a letter to Nature entitled "A Robust DNA Mechanical Device Controlled by Hybridization Topology." The authors are Hao Yan, Xiaoping Zhang, Zhiyong Shen and Nadrian C. Seeman.
Nadrian C. Seeman was born in Chicago in 1945. Following a BS in biochemistry from the University of Chicago, he received his Ph.D. in biological crystallography from the University of Pittsburgh in 1970. His postdoctoral training, at Columbia and MIT, emphasized nucleic acid crystallography. He has received numerous awards for his work on developing ways to construct three-dimensional objects, including cubes and more complex polyhedra, from synthetic DNA molecules. In August 1998, he reported in Nature that his lab had developed a reliable technique for arranging DNA molecules into two-dimensional crystals. The discovery of his lab's first DNA machine was also reported in Nature in January 1999.