Droplet microfluidics creates new opportunities for microbial engineering. Most microbial cultivations are carried out in bioreactors, which are usually bulky and consume a large amount of reagents and media. In this paper, we propose a microfluidic droplet-based microbioreactor for microbial cultivation. A microfluidic device was designed and fabricated to produce many droplet-based microbioreactors integrated with an AC electric field for the manipulation of these microbioreactors. Droplets encapsulating fluorescent Escherichia coli cells were generated, sorted, and trapped individually in small chambers. Fluorescence intensity was monitored to determine cell growth. An electric field with varying voltages and frequencies manipulates the droplets, simulating an oscillation effect. Initial results showed that electric field does not affect cell growth. A comparison with shake flask showed that a similar standard growth curve is obtained when cultivating at room temperature. This device has the potential for making droplet-based microbioreactors an alternative for microbial engineering research.
Keywords: E. coli; microbioreactor; microfluidics; oscillation and AC electric field.