A DNA bipedal nanowalker with a piston-like expulsion stroke

Abstract

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.

Controlling the preferential motion of chiral molecular walkers on a surface

“…Inspired by these biological systems, successful DNA track nano-walkers have been developed. [13][14][15] The behaviours of many other molecules have also been investigated in terms of their ability to walk or rotate preferentially in a particular direction either driven by a laser pulse, 16 chemical reactions, [17][18][19][20] electric eld, [21][22][23][24] temperature, 25 or a combination of different stimuli. 26 A ratchet-like behaviour has been observed in colloidal particles, 27 an articial motor system designed to replicate a realistic motor protein, 28 cold atoms in optical lattices, [29][30][31] nanoparticles in solution, 32,33 SQUIDs, 34 soliton transport, 35 nanopores in polymer lms, 36 polarons in diatomic molecular chains, 37 superparamagnetic particles, 38 and many other cases.…”

Mechanisms, Methods of Tracking and Applications of DNA Walkers: A Review

“…Further optimizations to the design asymmetry and utilization of knowledge of DNA topology and structural behavior of DNA, like the difference in kinetic rates of DNA duplex unzipping and shearing, may lead to improved and preferential forward binding, increasing fuel efficiency. [48,62] It was also shown that limiting the length of the walker is important for preserving forward moving bias, namely due to limiting its reach and preventing it from skipping steps or negating the effects of asymmetric design. [63] On the other hand, precisely controlling the length of the walker spacer can be an effective engine for powering the walker, as was shown, to move with an inchworm gait.…”

Light-Powered Micro/Nanomotors

“…Inspired by kinesin, researchers have developed artificial walkers from DNA, and the molecules can take a step forward based on DNA cleavage and ligation. By using light as an energy source, DNA walkers can mimic the function of biological motors in cargo transport and biosynthesis [ 68 , 69 , 70 , 71 ]. Since then, various types of light-powered molecular motors were developed gradually.…”