Fig. 1. Design of a microfluidic platform to investigate the role of spatiotemporal parameters in microbial consortia.
a Schematic of the microfluidic device. The inlets I11, I12 or I21, I22 connect to the outlets O1 or O2, respectively, and allow temporal control of the environmental conditions. Cells are initially seeded into growth chambers and the continuous flow of media through the main channels removes excess cells. Pairs of growth chambers are separated by a lattice of pillars, defined as the interaction channel, which allows diffusion of biomolecules and prevents cells from entering the interaction channel. The device has ten pairs of growth chambers for each separation distance. b Top: schematic of the genetic circuit in the E. coli sender and receiver strains. In the sender strain, the operon containing the synthetase LuxI and GFP is induced in response to arabinose. The synthetase LuxI produces the acyl-homoserine lactone (3-oxo-C6-HSL or AHL), which diffuses through the interaction channel into the receiver strain growth chamber. In the receiver strain, AHL binds to LuxR to form an activated LuxR–AHL complex, which in turn activates expression of RFP driven by a LuxR-regulated promoter. Bottom: overlaid representative fluorescence and phase-contrast microscope images of the sender and receiver strains in the device for each interaction channel length. The scale bar represents 25 μm. c GFP fluorescence in sender growth chambers as a function of time. The vertical line indicates the time at which arabinose was introduced. Shaded regions represent one standard deviation from the mean. The dashed line denotes the model fit. d RFP fluorescence over time in the receiver growth chambers. The vertical line indicates the time at which arabinose was introduced. Shaded regions represent one standard deviation from the mean. The dashed line denotes the model fit. Source data are provided as a Source Data file.