Bacteria Accumulation in Confined Environments

Advancements in medicine and environmental remediation require investigation into bacterial transport and accumulation in confined geometries with the presence of flow. By looking at the dynamics of Escherichia coli bacteria in microfluidic channels of irregular cross-section, we identify a phenomenon of accumulation of bacteria in specific regions of the channel depending on the flow. We believe this accumulation results from the downstream and upstream distances covered by bacteria as they swim along the solid boundaries of the microchannel. To prove our hypothesis, we developed unique experiments for long-distance tracking of individual bacteria over macroscopic distances of a few millimeters. Our experimental findings can be rationalized through stochastic simulations incorporating the individual bacterial behavior as a function of their local environment. Our research provides insight into macroscopic transport processes in biological or soil networks.