In Vivo Microrheology Reveals Local Elastic and Plastic Responses Inside 3D Bacterial Biofilms

• Published in: Advanced materials (Weinheim) 2024-07, Vol.36 (29), p.e2314059-n/a
• Main Authors: Ohmura, Takuya, Skinner, Dominic J., Neuhaus, Konstantin, Choi, Gary P. T., Dunkel, Jörn, Drescher, Knut
• Format: Article
• Language: English
• Subjects: Bacteria; biofilm; Biofilms; Biomechanics; Elastic anisotropy; Elastic properties; extracellular matrix; Force distribution; force inference; In vivo methods and tests; Mechanical properties; Modulus of elasticity; Plastic foam; Polysaccharides; rheology; shear flow; Shear stress; single‐cell tracking; Spatial distribution; Spatial resolution
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202314059

Bacterial biofilms are highly abundant 3D living materials capable of performing complex biomechanical and biochemical functions, including programmable growth, self‐repair, filtration, and bioproduction. Methods to measure internal mechanical properties of biofilms in vivo with spatial resolution on the cellular scale have been lacking. Here, thousands of cells are tracked inside living 3D biofilms of the bacterium Vibrio cholerae during and after the application of shear stress, for a wide range of stress amplitudes, periods, and biofilm sizes, which revealed anisotropic elastic and plastic responses of both cell displacements and cell reorientations. Using cellular tracking to infer parameters of a general mechanical model, spatially‐resolved measurements of the elastic modulus inside the biofilm are obtained, which correlate with the spatial distribution of the polysaccharides within the biofilm matrix. The noninvasive microrheology and force‐inference approach introduced here provides a general framework for studying mechanical properties with high spatial resolution in living materials. Bacterial biofilms are highly abundant 3D living materials capable of performing complex biomechanical and biochemical functions. A general method is developed to measure internal mechanical properties of biofilms in vivo with spatial resolution on the cellular scale, leading to the discovery that the elastic modulus inside biofilms correlates with the spatial distribution the polysaccharide component of the biofilm matrix.