Investigation of bacterial chemotaxis using a simple three-point microfluidic system

A three-point microfluidic system was developed and used to experimentally verify bacterial chemotaxis with known chemoeffectors. Using pneumatically-controlled micro-valves, the device was able to regulate microscale flows and created concentration gradients that allowed GFP-labelled Escherichia coli cells to interact with an environment that contained a chemoattractant and a chemorepellent. Having two separate possible paths (left and right) for the bacteria to move forward, this device also allowed for imaging processing based removal of noisy data, if adirectional bias was present. This device could be useful for quantitative analysis of chemotactic behaviors with minimal technical requirements, and could motivate the development of future devices based on this concept.