1 / 14

By Ismaël Duchesne , Simon Rainville and Tigran Galstian

DSCG liquid crystal’s viscosity: Insight into the motility of bacteria in an anisotropic liquid environment. By Ismaël Duchesne , Simon Rainville and Tigran Galstian. In this talk Anisotropic medium: DSCG liquid crystal

loyal
Télécharger la présentation

By Ismaël Duchesne , Simon Rainville and Tigran Galstian

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DSCG liquid crystal’s viscosity: Insight into the motility of bacteria in an anisotropic liquid environment By Ismaël Duchesne, Simon Rainville and TigranGalstian • In this talk • Anisotropic medium: DSCG liquid crystal • Isotropic and anisotropic motility of flagellarbacteria (E. coli) • Speed and orientation of bacteria in DSCG solution • Viscosity of DSCG solution

  2. DSCG liquid crystal’s viscosity: Insight into the motility of bacteria in an anisotropic liquid environment • Anisotropic liquid environment: • Physical properties depend on the direction (as birefringence) • Flagellar bacteria: • Bacteria that may swims in aqueous medium by rotating theirs flagella • Why anisotropic motility: • Many biological tissues and media may be anisotropic (biofilms, enriched chitin soils...) • Difficult task: only few studies

  3. Anisotropic medium: nematic liquid crystal (LC) Temperature

  4. Lyotropic LC: cromolyn sodium salt (DSCG) Yu. A. Nastishin and al., Physical Review E, November 2004.

  5. Isotropic motility of bacteria: runs and tumbles Random walk source: Wikipedia

  6. Anisotropic motility of flagellar bacteria (E. coli)

  7. Experiments: montages Chamber and light-guided dark-field microscopy Microscope

  8. Results: bacterial motility Speed Orientation variation • Purely isotropic phase: as if there were no DSCG • Pretransitional phase: sticky effect • Anisotropic phase: decrease of speed and runs in the direction of the director

  9. Results: viscosity measurements(from diffusion of 0,2-2µm microspheres) Viscosity Axial ratio • Purely isotropic phase:little viscosity increase • Pretransitional phase: exponential viscosity increase • Anisotropic phase:anisotropic viscosity

  10. Can we explain the anisotropic motility with the anisotropic viscosity? Isotropic Anisotropic Beads diffusion Swimming bacteria

  11. Conclusion • Bacteria behave very differently in anisotropic media • Viscosity doesn't explain everything (active motility important) • “New” pretransitional phase • Viscosity increase (aggregation – threshold) • Sticky effect • New possibilities for controlling motion of microorganisms

  12. Acknowledgements • Dr Simon Rainville • phDstudents • Guillaume Paradis • Ismael Duchesne • Dr TigranGalstian • phDstudents • Karen Allahverdyan

  13. Viscosity dependency to the beads size

  14. Propulsive force of bacteria

More Related