Fluctuations can induce local nematic order and extensile stress in monolayers of motile cells. Issue 11 (17th February 2021)

• Record Type: Journal Article
• Authors: Vafa, Farzan; Bowick, Mark J.; Shraiman, Boris I.; Marchetti, M. Cristina
• Is Part Of: Soft matter. Volume 17:Issue 11(2021)
• Page Start: 3068
• Page End: 3073
• Publication Date: 2021-02-17
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/d0sm02027c
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : The combination of cells preferentially crawling along the nematic axis and fluctuating traction forces spontaneously generates local nematic order and extensile stress. 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.