(119b) Chemotaxis of E. Coli in a Microfluidic Device: Experiments and Simulations

Chemotaxis is the phenomena by which microorganisms find food, or move away from poisonous chemicals. Chemicals which are capable of eliciting such a response from chemotactic cells are called chemotactants. Chemotactants may act as attractants (chemoattractants), in which case the chemotactic cell will move towards them, thereby exhibiting a positive response. Some chemicals act as repellents (chemorepellents), in which case the chemotactic cell will move away from them, thereby exhibiting a negative response. The understanding of this behavior is important, because of its relevance in cancer, immunology and microbiology.

In the present work, we describe a simple method to create stable chemical gradients in a microfluidic device in the absence of fluid flow. The microfluidic device is fabricated in poly(dimethylsiloxane) (PDMS) using soft-lithography. The gradients are measured in both, space and time using a fluorescent glucose 2-(N-(7-nitrobenz-2-oxa-1,3- diazol-4-yl)amino)-2-deoxyglucose (2-NBDG) which acts as chemoattractant for E.coli. We quantify the chemotaxis of E.coli to different gradients and compare the experimental results with the predictions of existing theoretical models of the signaling pathways.