Fig. 1: 4S biofilm growth under constant flow in the millifluidic channel.
a A square channel (1 mm × 1 mm and 30 mm in length) continuously fed with growth medium at 1 mL/h was positioned on a microscope stage thermostatically maintained at 30 °C. Images of 0.15 µm2 in size, covering nearly half of the width of the channel from the edge to the middle (black rectangle), were taken every 10 min. b Zoomed in images corresponding to the gray squares in a at time t = 10 min (left upper); 2h30 (center upper); 5 h (right upper); 18 h (left lower); 30 h (center lower); and 35 h (right lower), scale bar represents 30 µm (c). The µOD—calculated from transmitted light images, i.e., ln(I0/I), and proportional to biomass—as a function of time. The intensity I is averaged over all of the pixels in the 0.15 µm2 image (black frame in a). d Derivative of the µOD signal with respect to time. The red arrows show maxima of the expansion rate. Light curves are from three independent biological replicates, and the bold curve is the smoothed average.
