Fluctuations can induce local nematic order and extensile stress in monolayers of motile cells

Abstract

Recent experiments in various cell types have shown that two-dimensional tissues often display local nematic order, with evidence of extensile stresses manifest in the dynamics of topological defects. Using a mesoscopic model where tissue flow is generated by fluctuating traction forces coupled to the nematic order parameter, we show that the resulting tissue dynamics can spontaneously produce local nematic order and an extensile internal stress. A key element of the model is the assumption that in the presence of local nematic alignment, cells preferentially crawl along the nematic axis, resulting in anisotropy of fluctuations. Our work shows that activity can drive either extensile or contractile stresses in tissue, depending on the relative strength of the contractility of the cortical cytoskeleton and tractions by cells on the extracellular matrix.

arXiv comment6 pages, 1 figure. v2: minor edits and clarifying comments

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Cited by in corpus (8)

• Polar Fluctuations Lead to Extensile Nematic Behavior in Confluent Tissues
• Shape-tension coupling produces nematic order in an epithelium vertex model
• Spontaneous rotation of active droplets in two and three dimensions
• Fluctuation-induced dynamics of nematic topological defects
• Vorticity phase separation and defect lattices in the isotropic phase of active liquid crystals
• Cell sorting by active forces in a phase-field model of cell monolayers
• Traction and Stress Control Formation and Motion of +1/2 Topological Defects in Epithelial Cell Monolayers
• Noise-induced transitions from contractile to extensile active stress in isotropic fluids