Analysis of Flow-Based Microfluidic Gradient Generators for the Study of Bacterial Chemotaxis

Abstract

Chemotaxis is a phenomenon which enables cells to sense concentrations of certain chemical species in their microenvironment and move towards chemically favorable regions. This behavior is best understood in the bacteria Escherichia coli, which exhibits chemotaxis towards a variety of energy sources and signaling molecules. Recent advances in microbiology have engineered the chemotactic properties of bacteria to perform novel functions, but traditional methods of characterizing chemotaxis are not sufficient for such complex applications.

The field of microfluidics offers solutions in the form of gradient generators. Many of these gradient generators are flow-based, where a chemical species diffuses across a solution moving through a microchannel. A microfluidic gradient generator was explored as a chemotaxis platform. Sources of error during experimental operation and methods of mitigating this error were demonstrated, and the fundamental theory behind these devices was examined. These devices were determined to be inadequate for the study of bacterial chemotaxis.