Energy efficient nanowalker

7 Jul 2016. NUS biophysicists have invented an artificial enzymatic nanowalker with record fuel efficiency by mimicking biological counterparts.

Replicating the efficient use of chemical energy by biological nanomotors has always been a goal of researchers working in the nanotechnology and energy space. A research team led by Prof Zhisong WANG, comprising graduate students and research fellows from the Department of Physics in NUS designed and demonstrated an autonomous bipedal nanowalker (walking nanomotor) made of DNA that used less than two fuel molecules to “walk” a step forward. This achievement is a leap forward, breaking the threshold (generally assumed to be two fuel molecules per step) for chemically-powered machines which are reported to date.

Similar to biomotors in living cells, this new nanowalker is an enzyme. This enzymatic nanomotor is able to initiate the chemical reaction that allows it to move forward without permanently changing itself or the track which it is moving on. The research team has demonstrated a sustained motion by the nanowalker on an extended double-stranded track, moving at a speed comparable to "burn-bridge" motors. "Burn-bridge" motors are nanowalkers that are enzymes too but consume their tracks as fuel to power their movements. Mimicking its biological counterparts, this artificial nanowalker uses multiple "chemomechanical gates" to realise a physical mechanism which can efficiently harvest chemical energy at the single-molecule level – it walks by always picking up its back leg first and not its front leg.

This study provides rich insights into the physical effects which can facilitate the harvesting of chemical energy at the single-molecule level. Research findings from this motor system can guide future development on chemically powered nanomotors towards replicating the efficient, repeatable, automatic and mechanistically sophisticated transportation seen in biomotor-based intracellular transport exhibited in living cells. This is beyond the capability of the current generation of burn-bridge motors.

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Figure illustrates the nanowalker’s motion powered by fuel consumption. [Image credit: Molecular Motors Lab, NUS]

 

Reference

Liu MH., Cheng J., Tee SR., Sreelatha S., Loh IY., Wang ZS. "Biomimetic Autonomous Enzymatic Nanowalker of High Fuel Efficiency". ACS Nano (2016). DOI: 10.1021/acsnano.6b01035.