Figure 3. DIC images of oral biofilm cells on Ge surfaces pulse-treated with KSL-free (a-c) and KSL-containing (50 µg/mL) medium (d-f). Pulsed treatment (30 min at 0.2 mL/min at two-hour intervals) initiated 4 hrs (A) or 6 hrs (B) after inoculation. Growth of biofilms was greatly inhibited in the flow chamber pulse-treated with KSL 4 hrs, but not 6 hrs, after inoculation. Images of treated vs. untreated biofilm cells were obtained at intervals of 2 hrs (a,d), 6 hrs (b,e), and 10 hrs (c,f) after inoculation of salivary bacteria into the parallel chambers of the dual-flow cell. The data represent the results of 1 of the 3 separate experiments. Magnification, 200X. Bars represent 50 µm.