Transport and retention of motile cells in a complex microsystem comprising dead-end pores

Disordered microstructures comprising dead-end pores are prevalent in soil, membranes and biological tissues. Predicting transport and dispersal patterns of microorganisms in such media is important for various natural and bio-engineered systems. Herein, we study the transport of motile and non-motile E. Coli bacteria cells through a complex micromodel described in [1]. The prediction of bacteria transport in such systems is challenging due to their complex swimming behavior within confined structures. Based on microfluidic experiments, we observe that motile cells tend to migrate into the dead-end pores unlike their non-motile counterparts, leading to higher retention of motile cells and consequent accumulation of biomass inside dead-end pores. To predict the observed behavior numerically, we simultaneously solve a set of Langevin equations for active elongated microswimmers. Simulation results agree well with our experimental retention curves. Further, based on the simulated trajectories we uncover how a motile cell migrates from a transmitting channel into a dead-end pore.

 

[1] Bordoloi, A.D, Scheidweiler, D., Dentz, M., Bouabdellaoui, M., Abbarchi, M. and P. de Anna, Structure induced vortices control anomalous dispersion in porous media,  2021 arXiv preprint arXiv:2112.12492