Intercellular friction and motility drive orientational order in cell monolayers

Area of Science:

• Physics of complex systems
• Biophysics
• Computational biology

Background:

• Spatiotemporal patterns in multicellular systems are crucial for understanding tissue dynamics in development and disease.
• Cellular collectives exhibit emergent behaviors influenced by cell properties and interactions.

Purpose of the Study:

• To numerically investigate the behavior of deformable cell monolayers with intercellular friction.
• To explore the relationship between intercellular friction, cell motility, and emergent order.
• To model the coupling between topological defects and cellular mechanics.

Main Methods:

• Multiphase field modeling of near-confluent cell monolayers.
• Numerical simulations varying intercellular friction and cell motility.
• Analysis of solid-liquid transitions, nematic order, and topological defects.

Main Results:

• Varying friction and motility induce a solid-liquid transition and local nematic order.
• Intercellular friction increases monolayer viscosity, enhancing flow correlations and nematic order.
• Hexatic and nematic order are coupled; a model explains defect colocalization with cell overlap.

Conclusions:

• Results provide a mechanical basis for observed nematic/hexatic order in multicellular systems.
• Topological defects coinciding with cell overlap suggest a mechanism for cellular extrusion.
• The study identifies a generic pathway to couple topological and physical effects in cellular collectives.