Fig. 4: A streamer of acidic pH is evident in the downstream flow of P. aeruginosa biofilm microcolonies.
From: Fluorescent nanosensors reveal dynamic pH gradients during biofilm formation
Time-lapse images of a P. aeruginosa biofilm grown in a BioFlux flow cell and imaged using a fluorescence Nikon widefield microscope. a Time-lapse imaging of a P. aeruginosa biofilm grown in a BioFlux flow cell after 7 h (start of microcolony formation), 10, 13 and 16 h. Red streaks being released downstream by the microcolonies into the medium after 13 h of growth are indicated by the white arrows. Positively charged pH-sensitive polyacrylamide nanosensor were included at 5 mg mL−1 to visualise the red streaks. Scale bars represent 50 µm, with red and green channel being represented. b Fluorescence intensity of OG-FAM and TAMRA was measured using wide-field images in ImageJ and the ratio is plotted against the time of incubation starting after 7 h when microcolony formation occurred. Error bars represent standard error measured for different areas of the images, where n = 6. To view the movie, see Supplementary Movie 1.
