The nonlinear motion of cells subject to external forces

• Published in: Soft matter Vol. 18; no. 47; pp. 98 - 916
• Main Authors: Ioratim-Uba, Aondoyima, Loisy, Aurore, Henkes, Silke, Liverpool, Tanniemola B
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 07.12.2022; The Royal Society of Chemistry
• Subjects: Chemistry; Drops (liquids); Nonlinear response; Substrates; Traction
• ISSN: 1744-683X; 1744-6848; 1744-6848
• DOI: 10.1039/d2sm00934j

To develop a minimal model for a cell moving in a crowded environment such as in tissue, we investigate the response of a liquid drop of active matter moving on a flat rigid substrate to forces applied at its boundaries. We consider two different self-propulsion mechanisms, active stresses and treadmilling polymerisation, and we investigate how the active drop motion is altered by these surface forces. We find a highly non-linear response to forces that we characterise using drop velocity, drop shape, and the traction between the drop and the substrate. Each self-propulsion mechanism gives rise to two main modes of motion: a long thin drop with zero traction in the bulk, mostly occurring under strong stretching forces, and a parabolic drop with finite traction in the bulk, mostly occurring under strong squeezing forces. In each case there is a sharp transition between parabolic, and long thin drops as a function of the applied forces and indications of drop break-up where large forces stretch the drop. To develop a minimal model for a cell moving in a crowded environment such as in tissue, we investigate the response of a liquid drop of active matter moving on a flat rigid substrate to forces applied at its boundaries.