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. 2008 Dec 29;75(5):1308–1314. doi: 10.1128/AEM.01900-08

FIG. 4.

FIG. 4.

Transport of CPC (top panels) and Allura red dye (bottom panels) through S. epidermidis NJ9709 biofilms. (A and B) Centrifugal filter device assay. Agents were added to the chambers of filter devices and perfused through the filters by low-speed centrifugation. Values show the concentration of the agent in the flowthrough volume (for CPC) or the absorbance of the flowthrough solution (for Allura red dye) for control filters inoculated with sterile TSB (Blank filter), filters inoculated with NJ9709 (Biofilm), filters inoculated with NJ9709 and cultured in the presence of 20 μg of dispersin B ml−1 (DspB in broth), and filters inoculated with NJ9709 and perfused with 20 μg of dispersin B ml−1 by centrifugation prior to addition of the CPC (DspB in rinse). (C and D) Colony biofilm assay. For panel C, a CPC solution was pipetted directly onto a blood agar plate (No filter), onto a sterile filter placed on the agar surface (Blank filter), or onto a colony biofilm growing on a filter (Filter + biofilm). The CPC was allowed to absorb into the agar for 15 min, after which the filter was removed and the plate was inoculated with a lawn of NJ9709 cells. Values show the diameter of the zone of inhibition after 24 h. For panel D, a filter containing a colony biofilm was transferred to a petri dish containing 2% low-gelling-temperature agarose. Allura red dye was pipetted onto the agarose surface, filter, or colony biofilm as described for panel C and allowed to absorb into the agar for 15 min. Values show the absorbance (at 490 nm) of an agarose plug containing the diffused Allura red dye. (E and F) Cell culture insert assay. Cell culture inserts containing biofilms were rinsed, placed in a fresh microplate containing water, and filled with CPC or Allura red dye. Values show the concentrations of CPC (E) or Allura red dye (F) that diffused into the microplate well after 24 h. As a control, inserts inoculated with sterile TSB (Blank insert) were used. In all panels, values show means and ranges of the results of duplicate assays.