Biofilms of a GFP-expressing PAO1 strain were treated statically with 21.4 µM Cy5 (left), Cy5-tobramycin (center), or Cy5-ciprofloxacin (right) for 30 min. Confocal laser scanning micrographs were acquired every 2.5 min during the static incubation and a subsequent 30-min wash. Representative images after the static incubation and after the wash are shown. In the top row, the biomass is pseudo-colored green, and Cy5, purple. The bottom row shows the Cy5 channel alone in grayscale. Bar, 50 µm.