Guiding microscale swimmers using teardrop-shaped posts.
Ward, Michael D
Shelley, Michael J
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Davies Wykes, M., Zhong, X., Tong, J., Adachi, T., Liu, Y., Ristroph, L., Ward, M. D., et al. (2017). Guiding microscale swimmers using teardrop-shaped posts.. Soft Matter, 13 (27) https://doi.org/10.1039/c7sm00203c
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.
External DOI: https://doi.org/10.1039/c7sm00203c
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286792