SFB1313 Publication "The influence of motility on bacterial accumulation in a microporous channel"

New SFB 1313 publication, published in the context of research project C01 in Soft Matter:

"The influence of motility on bacterial accumulation in a microporous channel"

Authors

• Miru Lee (University of Stuttgart)
• Christoph Lohrmann (University of Stuttgart, SFB 1313 research project C01)
• Kai Szuttor (University of Stuttgart)
• Harold Auradou (Université Paris-Saclay)
• Christian Holm (University of Stuttgart, SFB 1313 research project C01)

Abstract

We study the transport of bacteria in a porous media modeled by a square channel containing one cylindrical obstacle via molecular dynamics simulations coupled to a lattice Boltzmann fluid. Our bacteria model is a rod-shaped rigid body which is propelled by a force-free mechanism. To account for the behavior of living bacteria, the model also incorporates a run-and-tumble process. The model bacteria are capable of hydrodynamically interacting with both of the channel walls and the obstacle. This enables the bacteria to get reoriented when experiencing a shear-flow. We demonstrate that this model is capable of reproducing the bacterial accumulation on the rear side of an obstacle, as has recently been experimentally observed by [G. L. Miño, et al., Adv. Microbiol., 2018, 8, 451] using E. coli bacteria. By systematically varying the external flow strength and the motility of the bacteria, we resolve the interplay between the local flow strength and the swimming characteristics that lead to the accumulation. Moreover, by changing the geometry of the channel, we also reveal the important role of the interactions between the bacteria and the confining walls for the accumulation process.