Abstract
We study cell navigation in spatiotemporally complex environments by developing a microfluidic racetrack device that creates a traveling wave with multiple peaks and a tunable wave speed. We find that while the population-averaged chemotaxis drift speed increases with wave speed for low wave speed, it decreases sharply for high wave speed. This reversed dependence of population-averaged chemotaxis drift speed on wave speed is caused by a “barrier-crossing” phenomenon, where a cell hops backwards from one peak attractant location to the peak behind by crossing an unfavorable (barrier) region with low attractant concentrations. By using a coarse-grained model of chemotaxis, we map bacterial motility in an attractant field to the random motion of an overdamped particle in an effective potential. The observed barrier-crossing phenomenon of living cells and its dependence on the spatiotemporal profile of attractant concentration are explained quantitatively by Kramers reaction rate theory.
- Received 26 July 2016
DOI:https://doi.org/10.1103/PhysRevLett.118.098101
© 2017 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
Racing Bacteria
Published 28 February 2017
Bacteria track fast-moving chemical signals by hopping from one chemically favorable region to another.
See more in Physics