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Issue 27, 2017
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Guiding microscale swimmers using teardrop-shaped posts

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The swimming direction of biological or artificial microscale swimmers tends to be randomised over long time-scales by thermal fluctuations. Bacteria use various strategies to bias swimming behaviour and achieve directed motion against a flow, maintain alignment with gravity or travel up a chemical gradient. Herein, we explore a purely geometric means of biasing the motion of artificial nanorod swimmers. These artificial swimmers are bimetallic rods, powered by a chemical fuel, which swim on a substrate printed with teardrop-shaped posts. The artificial swimmers are hydrodynamically attracted to the posts, swimming alongside the post perimeter for long times before leaving. The rods experience a higher rate of departure from the higher curvature end of the teardrop shape, thereby introducing a bias into their motion. This bias increases with swimming speed and can be translated into a macroscopic directional motion over long times by using arrays of teardrop-shaped posts aligned along a single direction. This method provides a protocol for concentrating swimmers, sorting swimmers according to different speeds, and could enable artificial swimmers to transport cargo to desired locations.

Graphical abstract: Guiding microscale swimmers using teardrop-shaped posts

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Publication details

The article was received on 26 Jan 2017, accepted on 21 Apr 2017 and first published on 24 Apr 2017

Article type: Paper
DOI: 10.1039/C7SM00203C
Soft Matter, 2017,13, 4681-4688

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    Guiding microscale swimmers using teardrop-shaped posts

    M. S. Davies Wykes, X. Zhong, J. Tong, T. Adachi, Y. Liu, L. Ristroph, M. D. Ward, M. J. Shelley and J. Zhang, Soft Matter, 2017, 13, 4681
    DOI: 10.1039/C7SM00203C

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