L2C Colloquia

Bacteria transport close to surfaces: from rheotaxis to upstream contamination

Sommaire :

Individual bacteria transported in viscous flows, show complex interactions with flows and bounding surfaces resulting from their complex shape as well as their activity. Under- standing these transport dynamics is crucial, as they impact soil contamination, transport in biological conducts or catheters, and constitute thus a serious health thread.

Here we investigate the trajectories of individual E-coli bacteria in confined geometries under flow, using microfluidic model systems in bulk flows as well as close to surfaces using a novel Langrangian 3D tracking method. Combining experimental observations and mod- eling we elucidate the origin of upstream swimming, lateral drift or persistent transport along corners.