Biological & Soft Matter Seminar: Cells as Active Nematic Liquid Crystals

Abstract:

An important feature of materials made of active particles is the emergence of coherent collective motion, examples ranging from fish schools down to biopolimer solutions. In cells collective dynamics give rise to tissue self-shaping during development, regeneration, cancer invasion and etc. Accumulating experimental evidence shows that various cell types organized as nematic liquid crystal. I will present experiments showing spontaneous emergence of collective flows in confined spindle-shaped cell cultures, interpreted as a Fréedericksz transition controlled by the activity of the cells. I will also show meso-scale turbulence dynamics in epithelial cell culture that occurs at low Reynolds numbers. The mechanism behind these phenomena will be discussed in the framework of the active gels theory.