title: Time-resolved biofilm deformation measurements using optical coherence tomography.
abstract: The interaction of shear stress with the biofilm leads to a dynamic deformation, which is related to the structural and material characteristics of biofilms. We show how optical coherence tomography can be used as an imaging technique to investigate the time-resolved deformation on the biofilm mesoscale as well as to estimate mechanical properties of the biofilm. For the first time time-resolved deformation from cross-sectional views of the inner biofilm structure could be shown. Changes in the biofilm structure and rheological properties were calculated from cross sections in real-time and time-lapsed measurements. Heterotrophic biofilms were grown in a flow cell set-up at low shear stress of τw  = 0.01 Pa. By applying higher shear stress elastic and viscoelastic behavior of biofilms were quantified. Deformation led to a change in biofilm conformation and allowed to estimate rheological properties. Assuming an ideal wall shear stress calculation, the shear modulus G = 29.7 ± 1.7 Pa and the Young's modulus E = 36.0 ± 2.6 Pa were estimated.
authors: Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 1, D-76131 Karlsruhe, Germany. florian.blauert@kit.edu.
authors: Florian
authors: F
authors: Blauert
authors: Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 1, D-76131 Karlsruhe, Germany.
authors: Harald
authors: H
authors: Horn
authors: Chair of Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 1, D-76131 Karlsruhe, Germany.|Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.
authors: Michael
authors: M
authors: Wagner
mesh_terms: D018441:Biofilms; D001696:Biomechanical Phenomena / Q000502:physiology; D055119:Elastic Modulus / Q000502:physiology; D033081:Shear Strength / Q000502:physiology; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: biofilm rheology; mechanical properties; mesoscale; optical coherence tomography; shear and Young's modulus; time-resolved deformation