In JoVE (1)
Other Publications (1)
Articles by Kais Zrelli in JoVE
Remote Magnetic Actuation of Micrometric Probes for in situ 3D Mapping of Bacterial Biofilm Physical Properties Olivier Galy1, Kais Zrelli1, Patricia Latour-Lambert2, Lyndsey Kirwan3, Nelly Henry1,3 1Physicochime Curie, CNRS UMR 168, Institut Curie, Sorbonne Universités, UPMC, 2Unité de Génétique des Biofilms, Institut Pasteur, 3Laboratoire Jean Perrin, CNRS UMR 8237, Sorbonne Universités, UPMC This paper shows an original methodology based on the remote actuation of magnetic particles seeded in a bacterial biofilm and the development of dedicated magnetic tweezers to measure in situ the local mechanical properties of the complex living material built by micro-organisms at interfaces.
Other articles by Kais Zrelli on PubMed
Mapping of Bacterial Biofilm Local Mechanics by Magnetic Microparticle Actuation Biophysical Journal. Sep, 2012 | Pubmed ID: 22995513 Most bacteria live in the form of adherent communities forming three-dimensional material anchored to artificial or biological surfaces, with profound impact on many human activities. Biofilms are recognized as complex systems but their physical properties have been mainly studied from a macroscopic perspective. To determine biofilm local mechanical properties, reveal their potential heterogeneity, and investigate their relation to molecular traits, we have developed a seemingly new microrheology approach based on magnetic particle infiltration in growing biofilms. Using magnetic tweezers, we achieved what was, to our knowledge, the first three-dimensional mapping of the viscoelastic parameters on biofilms formed by the bacterium Escherichia coli. We demonstrate that its mechanical profile may exhibit elastic compliance values spread over three orders of magnitude in a given biofilm. We also prove that heterogeneity strongly depends on external conditions such as growth shear stress. Using strains genetically engineered to produce well-characterized cell surface adhesins, we show that the mechanical profile of biofilm is exquisitely sensitive to the expression of different surface appendages such as F pilus or curli. These results provide a quantitative view of local mechanical properties within intact biofilms and open up an additional avenue for elucidating the emergence and fate of the different microenvironments within these living materials.