Mechanical-Kinetic Modeling of a Molecular Walker from a Modular Design Principle，PHYSICAL REVIEW APPLIED 7, 024020 (2017)；
Ruizheng Hou,1,2,* Iong Ying Loh,3,4 Hongrong Li,1,2 and Zhisong Wang3,4

1Department of Applied Physics, School of Science, Xi’an Jiaotong University, Xi'an 710049, Shaan Xi, China

2Institute of Quantum Optics and Quantum Information, Xi’an Jiaotong University, Xi’an 710049, Shaan Xi, China

3Department of Physics, National University of Singapore, Singapore 117542, Singapore

4NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117542, Singapore

(Received 30 June 2016; revised manuscript received 27 November 2016; published 17 February 2017)

Artificial molecular walkers beyond burnt-bridge designs are complex nanomachines that potentially replicate biological walkers in mechanisms and functionalities. Improving the man-made walkers up to performance for widespread applications remains difficult, largely because their biomimetic design principles involve entangled kinetic and mechanical effects to complicate the link between a walker’s construction and ultimate performance. Here, a synergic mechanical-kinetic model is developed for a recently reported DNA bipedal walker, which is based on a modular design principle, potentially enabling manydirectionalwalkersdrivenbyalength-switchingengine.Themodelreproducestheexperimentaldata of the walker, and identifies its performance-limiting factors. The model also captures features common to the underlying design principle, including counterintuitive performance-construction relations that are explainedbydetailedbalance,entropyproduction,andbiascancellation.Whileindicatingalowdirectional fidelity for the present walker, the model suggests the possibility of improving the fidelity above 90% by a more powerful engine, which may be an improved version of the present engine or an entirely new engine motif, thanks to the flexible design principle. The model is readily adaptable to aid these experimental developments towards high-performance molecular walkers.
DOI: 10.1103/PhysRevApplied.7.024020