Feb 4, 2003
DNA nanomotor expands and contracts
The DNA machines created to date have commonly produced rotation or "scissor-like" opening and closing movements. Now researchers from the Muséum National d'Histoire Naturelle in France have made a DNA nanomotor that expands and contracts by up to 5 nm.
The machine consists of F21T, a single 21-base oligonucleotide, which switches between two states - an elongated double strand of DNA and a tightly coiled quadruplex. Adding a single strand of DNA as "fuel" provides the energy source for this change.
"The interconversion between two well defined topological states induces a 5 nm two-stroke, linear motor type movement," researcher Jean-Louis Mergny told nanotechweb.org. "Setting the machine was relatively easy, but improving the kinetics was a real challenge."
By researching a number of oligonucleotide sequences and various experimental conditions, the researchers created a system in which switching from the closed to the open state took less than 30 seconds, while the reverse process took 3 seconds.
"The sequence we are using is biologically relevant," added Mergny. "It corresponds to the human telomeric motif - the sequence found at the end of the chromosomes, called telomeres."
The scientists detected the nanomachine's movements by using fluorescence resonance energy transfer spectroscopy to track fluorescent groups attached to the ends of the F21T.
The nanomotor could have applications in the construction of two-dimensional crystals, the control of nanorobotic devices or in DNA computers. And linking one or both ends of the device to an organic or inorganic component could bring a number of new possibilities.
The scientists reported their work in the Proceedings of the National Academy of Sciences of the United States of America. Researchers from the University of Florida have also made a nanomotor that uses a duplex-quadruplex equilibrium. This work, which is based on a different DNA sequence, was detailed in Nano Letters.
About the author
Liz Kalaugher is editor of nanotechweb.org.