Microfluidic chemostat for measuring single cell dynamics in bacteria.

We designed a microfluidic chemostat consisting of 600 sub-micron trapping/growth channels connected to two feeding channels. The microchemostat traps E. coli cells and forces them to grow in lines for over 50 generations. Excess cells, including the mother cells captured at the start of the process, are removed from both ends of the growth channels by the media flow. With the aid of time-lapse microscopy, we have monitored dynamic properties such as growth rate and GFP expression at the single-cell level for many generations while maintaining a population of bacteria of similar age. We also use the microchemostat to show how the population responds to dynamic changes in the environment. Since more than 100 individual bacterial cells are aligned and immobilized in a single field of view, the microchemostat is an ideal platform for high-throughput intracellular measurements. We demonstrate this capability by tracking with sub-diffraction resolution the movements of fluorescently tagged loci in more than one thousand cells on a single device. The device yields results comparable to conventional agar microscopy experiments with substantial increases in throughput and ease of analysis.