Self-organization in tissues: Active nematic materials

Cells both actively generate and sensitively react to forces, typically behaving as elastic solids on short time-scales and resembling a viscous liquid on long time-scales. The long-term behavior is the most relevant to shaping of tissues, but long-term cell properties are difficult to measure because cells are adaptive entities that actively respond to external queues by changing their properties. Accumulating experimental evidences show that active nematic theory provides an excellent framework to help to dissect and understand the complex dynamics across different cell types. In our recent papers (Nature Physics 2018, Physical Review Letters 2018) [1, 2] we have shown existence of different nemato-dynamic modes and estimated multicellular physical properties (e.g. activity, viscosity, friction, Frank elastic constant) using high-throughput scanning. I will present spontaneous emergence of collective shear flows and activity driven turbulence. I will discuss the mechanism behind these phenomena and their effect on cell organization and function.

1. G. Duclos*, C. Blanch-Mercader*, V. Yashunsky*, G. Salbreux, J.F. Joanny, J. Prost, and P. Silberzan, Spontaneous shear flow in confined cellular nematics. Nature Physics, 2018. 14(7): p. 728-732 (* equal contribution).

2. Blanch-Mercader*, C., V. Yashunsky*, S. Garcia, G. Duclos, L. Giomi, and P. Silberzan, Turbulent Dynamics of Epithelial Cell Cultures. Phys Rev Lett, 2018. 120(20): p. 208101 (* equal contribution).