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.

动态 DNA 纳米技术产生了非平凡的自主行为，例如刺激引导的运动、计算和可编程分子组装。尽管取得了这些成功，但基于 DNA 的纳米机器仍存在动力学缓慢的问题，需要几分钟或更长时间才能进行少量操作。在这里，我们通过对在互补寡核苷酸领域进行侧翻运动的新型 DNA 步行器进行单分子优化，来追求 DNA 纳米技术中一类重要反应的速度限制——立足点交换。在优化此 DNA 'acrobat' 以实现快速运动后，我们测量了接近 1 s ^-1的步进速率常数，这比以前的 DNA 步行者快 10 到 100 倍。最后，我们使用单粒子跟踪来证明步行者在 10 分钟内移动数百纳米，与步进动力学的预测定量一致。这些结果表明，利用链置换可以显着提高各类 DNA 纳米机器的运行率。