Remote magnetic actuation of micrometric probes for in situ 3D mapping of bacterial biofilm physical properties.
Bacterial adhesion and growth on interfaces lead to the formation of three-dimensional heterogeneous structures so-called biofilms. The cells dwelling in these structures are held together by physical interactions mediated by a network of extracellular polymeric substances. Bacterial biofilms impact many human activities and the understanding of their properties is crucial for a better control of their development - maintenance or eradication - depending on their adverse or beneficial outcome. This paper describes a novel methodology aiming to measure in situ the local physical properties of the biofilm that had been, until now, examined only from a macroscopic and homogeneous material perspective. The experiment described here involves introducing magnetic particles into a growing biofilm to seed local probes that can be remotely actuated without disturbing the structural properties of the biofilm. Dedicated magnetic tweezers were developed to exert a defined force on each particle embedded in the biofilm. The setup is mounted on the stage of a microscope to enable the recording of time-lapse images of the particle-pulling period. The particle trajectories are then extracted from the pulling sequence and the local viscoelastic parameters are derived from each particle displacement curve, thereby providing the 3D-spatial distribution of the parameters. Gaining insights into the biofilm mechanical profile is essential from an engineer's point of view for biofilm control purposes but also from a fundamental perspective to clarify the relationship between the architectural properties and the specific biology of these structures.
Physicochime Curie, CNRS UMR 168, Institut Curie, Sorbonne Universités, UPMC.
Olivier
O
Galy
Physicochime Curie, CNRS UMR 168, Institut Curie, Sorbonne Universités, UPMC.
Kais
K
Zrelli
Unité de Génétique des Biofilms, Institut Pasteur.
Patricia
P
Latour-Lambert
Laboratoire Jean Perrin, CNRS UMR 8237, Sorbonne Universités, UPMC.
Lyndsey
L
Kirwan
Physicochime Curie, CNRS UMR 168, Institut Curie, Sorbonne Universités, UPMC; Laboratoire Jean Perrin, CNRS UMR 8237, Sorbonne Universités, UPMC; nelly.henry@upmc.fr.
Nelly
N
Henry
D018407:Bacterial Physiological Phenomena; D001431:Bacteriological Techniques / Q000379:methods*; D018441:Biofilms; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology; D005144:F Factor / Q000235:genetics; D008280:Magnetics / Q000295:instrumentation / Q000379:methods*; D010957:Plasmids / Q000235:genetics