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Spatial distribution of mechanical properties in Pseudomonas aeruginosa biofilms, and their potential impacts on biofilm deformation
  • Juan Pablo Pavissich,
  • Mengfei Li,
  • Robert Nerenberg
Juan Pablo Pavissich
Universidad Adolfo Ibanez
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Mengfei Li
University of Notre Dame
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Robert Nerenberg
University of Notre Dame
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The mechanical properties of biofilms can be used to predict biofilm deformation, for example under fluid flow. We used magnetic tweezers to spatially map the compliance of Pseudomonas aeruginosa biofilms at the micron scale, then used modeling to assess its effects on biofilm deformation. Biofilms were grown in capillary flow cells with Reynolds numbers (Re) ranging 0.28 to 13.9, bulk dissolved oxygen (DO) concentrations from 1 mg/L to 8 mg/L, and bulk calcium ion (Ca2+) concentrations of 0 and 100 mg CaCl2/L. Higher Re numbers resulted in more uniform biofilm morphologies. The biofilm was stiffer at the center of the flow cell than near the walls. Lower bulk DO led to more stratified biofilms. Higher Ca2+ led to increased stiffness and more uniform mechanical properties. Using the experimental mechanical properties, fluid-structure interaction models predicted up to 64% greater deformations for heterogeneous biofilms, compared to a homogeneous biofilms with the same average properties. However, the error depended on the biofilm morphology and flow regime. Our results show significant spatial mechanical variability exists at the micron scale, and that this variability can potentially affect biofilm deformation. The average mechanical properties, provided in many studies, should be used with caution when predicting biofilm deformation.

Peer review status:Published

06 Oct 2020Submitted to Biotechnology and Bioengineering
06 Oct 2020Submission Checks Completed
06 Oct 2020Assigned to Editor
10 Oct 2020Reviewer(s) Assigned
21 Nov 2020Editorial Decision: Revise Major
21 Nov 2020Review(s) Completed, Editorial Evaluation Pending
01 Jan 20211st Revision Received
02 Jan 2021Submission Checks Completed
02 Jan 2021Assigned to Editor
04 Jan 2021Editorial Decision: Accept
04 Jan 2021Review(s) Completed, Editorial Evaluation Pending
Apr 2021Published in Biotechnology and Bioengineering volume 118 issue 4 on pages 1564-1575. 10.1002/bit.27671