Time-resolved biofilm deformation measurements using optical coherence tomography

Area of Science:

• Microbiology
• Biophysics
• Materials Science

Background:

• Biofilms exhibit complex mechanical properties influenced by shear stress.
• Understanding biofilm deformation is crucial for predicting their behavior in various environments.

Purpose of the Study:

• To investigate time-resolved biofilm deformation using optical coherence tomography (OCT).
• To estimate the mechanical properties of biofilms, including elastic and viscoelastic behavior.
• To demonstrate OCT's capability for real-time, cross-sectional analysis of inner biofilm structure.

Main Methods:

• Heterotrophic biofilms were cultured in a flow cell under low shear stress (0.01 Pa).
• Optical coherence tomography was employed for time-resolved imaging of biofilm deformation.
• Shear stress was increased to quantify elastic and viscoelastic responses.
• Mechanical properties (shear modulus G, Young's modulus E) were calculated from deformation data.

Main Results:

• Time-resolved, cross-sectional views of inner biofilm structure deformation were achieved.
• Changes in biofilm conformation and rheological properties were calculated in real-time and time-lapsed measurements.
• The shear modulus (G = 29.7 ± 1.7 Pa) and Young's modulus (E = 36.0 ± 2.6 Pa) were estimated.

Conclusions:

• Optical coherence tomography is a powerful tool for studying biofilm mechanics at the mesoscale.
• This method allows for non-invasive, real-time quantification of biofilm deformation and mechanical properties.
• The findings provide valuable data for understanding biofilm structural integrity and response to fluid dynamics.