2.4 Biofilm deformation experiments
The synthetic biofilm or homogenized P. aeruginosa biofilm was inserted into a cylindrical support with a dimension of 1mm × 3mm (diameter × height) (Fig. 2). The biofilm cylinder-shaped support was glued inside a flow cell with a dimension of 25 cm × 10 mm × 10 mm (length × width × height). The flow was driven by gravity, and the flow rate was controlled with a valve on the influent line. The large size of the water reservoir and the short duration of the experiment led to minimal changes in water level in the water reservoir, therefore providing near-constant velocities. The flow rate (\(u_{1}\)) was measured by directing the effluent to a graduated cylinder. Biofilm morphologies were monitored and recorded using optical coherence tomography (OCT) (Ganymede II, Thorlabs GmbH, Lübeck, Germany). The image collection software was ThorImage OCT, Version 5.0.1. The cross-sectional images of biofilm were captured by recording a real-time video of the OCT output (SI V1-V2).