2.8. Surface coverage analysis using ImageJ

During biofilm cultivation, images from the capillaries were collected daily to document biofilm growth. Images were transferred to ImageJ v.1.45s (https://imagej.nih.gov/ij/) and converted to 8-bit. After scaling based on capillary length, surface areas of the capillaries were selected and analyzed by the ‘Plot profile’ feature. Background noise was obtained by selecting and plotting the regions next to the biofilms. Raw data of all plotted images were extracted as CVS file and assigned to Origin 2019 (OriginLab corp., Northampton, US) for further calculation. Surface coverage was determined subtracting all the values obtained from the plot profile of the sample images from the background noise constant and integrating along the capillary length.