Physics colloquium: “Bacterial Navigation of Narrow Channels”

Nuris Figueroa-Morales

University of Colorado @ Boulder, Physics Department

Abstract: 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 narrow microfluidic channels, we identify a phenomenon of upstream “super-contamination” of bacteria that depends on the flow. Bacteria navigate upstream over macroscopic distances at an average speed of 1millimiter per minute. We believe the evolution of the concentration 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 develop unique experiments for long-distance scanning of the channel over macroscopic distances of a few millimeters. Our experimental findings can be rationalized through stochastic simulations incorporating the long tail of individual bacterial run time, as appose to the classically assumed Poisson distribution of average 1second runs. Our research provides insight into macroscopic transport processes in biological or soil networks and demonstrates that the run-and-tumble statistics determine macroscopic bacterial transport properties.

Biography: Nuris Figueroa is an Assistant Professor of Physics at the University of Colorado Boulder. Her lab investigates the transport of microorganisms in complex environments, like viscoelastic and anisotropic liquids and complex porous geometries, using tools from microfluidics, quantitative video microscopy, and real time 3D tracking of bacteria and micro-particles. Her current interests focus on the dynamics of bacteria in the mucus of the respiratory, gastro-intestinal and reproductive tracts, as well as bacterial transport in relation with pollutants in soils. She holds Batchelors and Masters degrees in Physics from the University of Havana (Cuba), a PhD in Physics from Sorbonne University (France), and postdoctoral experience in Biomedical Engineering at Penn State.

All lectures in CoorsTek 140 unless otherwise noted