Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542.
Nanoscale. 2017 Aug 24;9(33):12142-12149. doi: 10.1039/c7nr03809g.
Artificial molecular walkers beyond burn-bridge designs are important for nanotechnology, but their systematic development remains difficult. Herein, we have reported a new rationally designed DNA walker-track system and experimentally verified a previously proposed general expulsion regime for implementing non-burn-bridge nanowalkers. The DNA walker has an optically powered engine motif that reversibly extends and contracts the walker via a quadruplex-duplex conformational change. The walker's extension is an energy-absorbing and force-generating process, which drives the walker's leg dissociation off-track in a piston-like expulsion stroke. The unzipping-shearing asymmetry provides the expulsion stroke a bias, which decides the direction of the walker. Moreover, three candidate walkers of different sizes were fabricated. Fluorescence motility experiments indicated two of them as successful walkers and revealed a distinctive size dependence that was expected for these expulsive walkers, but was not observed in previously reported walkers. This study identifies unique technical requirements for expulsive nanowalkers. The present DNA design is readily adapted for making similar walkers from other molecules since the unzipping-shearing asymmetry is common.
超越烧桥设计的人工分子步行者对于纳米技术很重要，但它们的系统发展仍然很困难。在此，我们报告了一种新的合理设计的 DNA 步行者-轨道系统，并通过实验验证了先前提出的用于实现非烧桥纳米步行者的一般逐出机制。DNA 步行者具有一个受光驱动的发动机结构，通过四联体-双螺旋构象变化可逆地延伸和收缩步行者。步行者的延伸是一个能量吸收和力产生的过程，它在活塞状的逐出冲程中驱动步行者的腿从轨道上解离。解链-剪切不对称性为逐出冲程提供了一个偏向，从而决定了步行者的方向。此外，制造了三个不同尺寸的候选步行者。荧光运动实验表明其中两个是成功的步行者，并揭示了预期的这些逐出步行者的独特尺寸依赖性，但在以前报道的步行者中没有观察到。这项研究确定了逐出纳米步行者的独特技术要求。由于解链-剪切不对称性很常见，因此本 DNA 设计很容易适用于制造其他分子的类似步行者。
