Figure 3. Emergent behavior in a long, narrow microfluidic trap.

We simulated a two-strain consortium growing in a two-dimensional trap open on all sides. Cells were removed from the simulation once center of mass crossed a trap boundary. We initialized the simulation by randomly placing several seed cells from each strain into the trap. Strains are non-interacting, with yellow and blue colors representing strain type. (a) After the trap filled, the strains organized themselves into vertically-oriented curvilinear stripes consisting of curvilinear columns of cells. Each such column functioned as a quasi-mother machine. (b) Empirical distribution of normalized cell compression over the length of the simulation. Each horizontal slice represents the empirical probability density for compression at a given trap depth. Mean compression is highest in the center of the trap and tapers quadratically, as our theoretical analysis of a mother machine predicts. The dimensions of the trap were 40 μm × 200 μm. All other parameters were set as in Figure 2. Spring compression is normalized to set the quadratic peak near 0.5.