Table 1. Ratio between the biofilm matrix area and the sessile cells area obtained from binary images of plasma-treated biofilms.

Plasma exposure time (min)	matrix area/cells area
0	1.75 ± 0.12 a
3	1.05 ± 0.13 b
30	0.46 ± 0.10 c

Ratio between the black pixel area in the binary image of the biofilm matrix stained with Calcofluor White and the black pixel area in the binary image of the biofilm cells stained with SYTO9. Biofilms were treated with plasma for 0, 3, and 30 min prior to staining. Images were binarized as indicated in Fig 3. Means are the average of the ratio of areas from 40 pictures acquired in 4 independent experiments. Different letters correspond to significantly different means (p<0.001).