Fig. 3

OMVs exhibit bactericidal and antibiofilm activities on S. mutans. S. mutans biofilms were grown on chamber-slides in BMGS for three days before treatment with (A) PBS, (B) 50 µg/mL, or (C) 100 µg/mL OMVs for 24 h. Following staining with LIVE/DEAD BacLight fluorescent dye (SYTO 9/propidium iodide), biofilms were subjected to optical dissection using confocal microscopy. Green: total biomass. Red: dead cells. Side bars indicate the thickness of the biofilms. Post-acquisition analyses of the fluorescent images were performed using COMSTAT 2.0. Treatments with OMVs or PBS were compared for (D) total biofilm biomass/dead cell biomass, (E) average thickness, and (F) roughness coefficient. Roughness coefficients of the biofilms were calculated as an indication of biofilm integrity. The results were analyzed using one-factor ANOVA. (** p < 0.01, **** p < 0.0001, NS = not significant)