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BP: Fachverband Biologische Physik

BP 24: Poster B: Active Biological Matter, Cell Mechanics, Systems Biology, Computational Biophysics, etc.

BP 24.1: Poster

Tuesday, March 23, 2021, 16:00–18:30, BPp

Chirality-induced rheotaxis of bacteria in bulk shear flows — •Guangyin Jing^1,2, Andreas Zöttl^2,3, Eric Clement², and Anke Lindner² — ¹Northwest University, Xian, China — ²ESPCI Paris, France — ³TU Wien, Austria

The interaction of swimming bacteria with shear flows controls their ability to explore complex environments [1], crucial to many societal and environmental challenges and relevant for microfluidic applications such as cell sorting. We combine experimental, numerical, and theoretical analysis, and present a comprehensive study of the transport of motile bacteria in shear flows [2]. Experimentally, we obtain with high accuracy and, for a large range of flow rates, the spatially resolved velocity and orientation distributions of run-and-tumble E. coli bacteria. They are in excellent agreement with the simulations of a kinematic model accounting for stochastic and microhydrodynamic properties and, in particular, the flagella chirality. Theoretical analysis reveals the scaling laws behind the average rheotactic velocity at moderate shear rates using a chirality parameter and explains the reorientation dynamics leading to saturation at large shear rates from the marginal stability of a fixed point. Our findings constitute a full understanding of the physical mechanisms and relevant parameters of bacteria bulk rheotaxis.

[1] A. J. T. M. Mathijssen, N. Figueroa-Morales, G. Junot, E. Clément, A. Lindner, and A. Zöttl, Nat. Comm. 10, 3434 (2019).

[2] G. Jing, A. Zöttl, E. Clement, and A. Lindner, Sci. Adv. 6, eabb2012 (2020).