Spatial Patterning of Microbial Consortia in Microfluidic Devices

As synthetic biology projects become more complex, circuits become larger and more demanding on the chassis strain. Expanding genetic circuits to two (or more) cooperating strains allows for better development of intricate circuits. These synthetic microbial consortia can provide an assembly line of specialized cells or a study of intercellular interactions (Brenner et al., 2008). When grown in microfluidic devices, strains can be identified by expression of unique fluorescent proteins. We have observed distinct spatial patterning of strains in different fluidic devices. These patterns affect communication between strains, can lead to competition for space, and alter the behavior of the circuit. We have tested non-communicating strains in fluidic devices to establish baseline patterns such as fluctuations in strain ratios over time or strains growing in bands of varying thickness. We used this information to determine the conditions that establish specific patterns in each device. Communicating strains were then tested to determine how these patterns affect signaling between strains. Finally, we are developing a fluorescence capable turbidostat to grow consortia with constant media while measuring fluorescence (Takahashi et al., 2015). While this does not allow for single cell resolution, it removes the influence of spatial patterning and may provide a better environment for studying microbial consortia.

Brenner K., You L., and Arnold F.H. (2008). Engineering microbial consortia: a new frontier in synthetic biology. Trends Biotechnol. 26, 483-9.

Takahashi C.N., Miller A.W., Ekness F., Dunham M.J., and Klavins E. (2015). A low cost, customizable turbidostat for use in synthetic circuit characterization. ACS Syn. Bio. 4, 32-38.