Motility and morphodynamics of confined cells

Area of Science:

• Biophysics
• Cellular Mechanics
• Hydrodynamics

Background:

• Biological cells exhibit complex behaviors like polarization, migration, and deformation.
• Understanding these dynamics is crucial for cell biology and disease research.
• Active forces within the cytoskeleton play a key role in cell mechanics.

Purpose of the Study:

• To introduce a minimal hydrodynamic model for confined biological cells.
• To investigate the dynamic behaviors arising from active cytoskeleton forces and solute activity.
• To provide an analytical framework for active deformable systems.

Main Methods:

• Developed a quasi-two-dimensional hydrodynamic model of a viscous droplet in the Darcy flow regime.
• Incorporated an active cytoskeleton force and a diffusive solute as a force transducer.
• Utilized linear stability analysis and nonlinear analysis to study system dynamics.

Main Results:

• The model predicts spontaneous symmetry breaking leading to cell polarization and motility.
• Higher solute activity induces Hopf bifurcations, resulting in coupled oscillations of cell shape and solute concentration.
• Nonlinear analysis revealed traveling-wave solutions with polarized shapes matching experimental observations.

Conclusions:

• The model offers an analytically tractable paradigm for active deformable systems.
• It demonstrates how coupled viscous hydrodynamics and diffusive force transducers drive cell dynamics.
• The findings provide insights into the fundamental mechanisms of cell migration and shape changes.