The Microchemostat represents the first implementation of chip-based bacterial continuous culture in dew-droplet-sized reactors. A highly complex web of tiny pumps and human-hair-sized water hoses delivers nutrients to each reactor, scrubs the walls, and takes out waste, all controlled by a multi-tasking computer. As it runs autonomously, this system eliminates pipetting, plating and hands-on culture handling while providing minute-by-minute data in the form of single-cell-resolved cell count, morphology, motility and gene expression information (via fluorescence reporters). It combines its ultra-low reagent consumption with its space-saving footprint into high throughput research at low cost.

Equivalent to shrinking the population of the World to that of Toronto, the microchemostat uses only a tear of nutrient broth for every gallon consumed by its conventional predecessors. For every million bacteria that a conventional culture adds to its population, the microchemostat adds only one to its own. Microchemostat populations are therefore proportionately less likely to mutate and evolve away from their genetic make-up during an experiment. To demonstrate this concept, we recently characterized the dynamics of Escherichia coli cells carrying a synthetic “population-control” circuit, which regulates cell density through a population-density-based feedback mechanism. Unprecedented temporal and single-cell resolved microchemostat readings captured dynamics such as delicate oscillations that eluded detection in conventional settings while prolonging the lifetime of the programmed circuit by an order of magnitude.

From optimizing industrial processes by characterizing bacteria under a matrix of conditions to drug-susceptibility testing in pharmaceutical discovery, the microchemostat will prove its value to the microbiology community.