Deflection of phototactic microswimmers through obstacle arrays

Abstract

We study the effect of inhomogeneous environments on the swimming direction of the microalgae \textit{Chlamydomonas Reinhardtii} (CR) in the presence of a light stimulus. Positive or negative phototaxis describe the ability of microorganisms to bias their swimming towards or away from a light source. Here we consider microswimmers with negative phototaxis in a microfluidic device with a microfabricated square lattice of pillars as obstacles. We measured a mean deflection of microswimmers that shows an interesting nonlinear dependence on the direction of the guiding light beam with respect to the symmetry axes of the pillar lattice. By simulating a model swimmer in a pillar lattice and analyzing its scattering behavior, we identified the width of the reorientation distribution of swimmers to be also crucial for the nonlinear behavior of the swimmer deflection. On the basis of these results we suggest in addition an analytical model for microswimmers, where the pillar lattice is replaced by an anisotropic scattering medium, that depends only on a scattering rate and the width of the reorientation distribution of swimmers. This flexible and handy model fits the experimental results as well. The presented analysis of the deflection of light guided swimmers through pillar lattice may be used for separating swimmers having different reorientation distributions.

References in corpus (22)

• Active Particles in Complex and Crowded Environments
• Numerical Simulations of Particulate Suspensions via a Discretized Boltzmann Equation Part I. Theoretical Foundation
• Microswimmers in Patterned Environments
• When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation
• Direct measurement of the flow field around swimming microorganisms
• Ciliary contact interactions dominate surface scattering of swimming eukaryotes
• Effective viscosity of microswimmer suspensions
• Diffusion, subdiffusion, and trapping of active particles in heterogeneous media
• Light control of the flow of phototactic microswimmer suspensions
• Microalgae scatter off solid surfaces by hydrodynamic and contact forces
• Scattering of biflagellate microswimmers from surfaces
• Optimized Diffusion of Run-and-Tumble Particles in Crowded Environments
• Transport and dispersion of active particles in periodic porous media
• Diffusion, subdiffusion and localisation of active colloids in random post lattices
• Simulating Colloid Hydrodynamics with Lattice Boltzmann
• Active particles in periodic lattices
• Effect of motility on the transport of bacteria populations through a porous medium
• Ideal circle microswimmers in crowded media
• Effective diffusivity of microswimmers in a crowded environment
• Photofocusing: Light and flow of phototactic microswimmer suspension
• A fine balance of chemotactic and hydrodynamic torques: when microswimmers orbit a pillar just once
• Dumbbell transport and deflection in a spatially periodic potential

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• Clogging, Dynamics and Reentrant Fluid for Active Matter on Periodic Substrates
• Active Matter Shepherding and Clustering in Inhomogeneous Environments
• The influence of obstacles on collective motion of self-propelled objects
• Pattern Formation and Transport for Externally Driven Active Matter on Periodic Substrates
• Future Directions for Active Matter on Ordered Substrates
• Behavioral transition of a fish school in a crowded environment
• Polarization and dynamic phases of aligning active matter in periodic obstacle arrays
• Programmable transport of rotating particles in obstacle arrays