Arizona State University Professor Hao Yan and his colleagues describe an innovative DNA walker, capable of rapidly traversing a prepared track. Rather than slow, tentative steps across a surface, the new DNA acrobat cartwheels head over heels, covering ground 10 to 100 times faster than previous devices.
Above -Hao Yan, director of the Biodesign Center for Molecular Design and Biomimetics, and his colleagues have developed a walking robot constructed from sequences of DNA. The robot uses a cartwheeling motion to rapidly cover distance. The new innovation opens the door to other DNA nanotechnology innovations in electronics, materials science and medicine. Graphic by Zhuoru Li
“It is exciting to see that DNA walkers can increase their speed significantly by optimizing DNA strand length and sequences; the collaborative effort really made this happen,” Yan said.
“The trick was to make the walker go head over heels, which is so much faster than the hopping used before — just as you would see in a kung fu action movie where the hero speeds up by cartwheeling to catch the villain,” Walter said.
The improvements in speed and locomotion displayed by the new walker should encourage further innovations in the field of DNA nanotechnology.
Dynamic DNA nanotechnology has yielded nontrivial autonomous behaviours such as stimulus-guided locomotion, computation and programmable molecular assembly. Despite these successes, DNA-based nanomachines suffer from slow kinetics, requiring several minutes or longer to carry out a handful of operations. Here, we pursue the speed limit of an important class of reactions in DNA nanotechnology—toehold exchange—through the single-molecule optimization of a novel class of DNA walker that undergoes cartwheeling movements over a field of complementary oligonucleotides. After optimizing this DNA ‘acrobat’ for rapid movement, we measure a stepping rate constant approaching 1 s−1, which is 10- to 100-fold faster than prior DNA walkers. Finally, we use single-particle tracking to demonstrate movement of the walker over hundreds of nanometres within 10 min, in quantitative agreement with predictions from stepping kinetics. These results suggest that substantial improvements in the operating rates of broad classes of DNA nanomachines utilizing strand displacement are possible.