Elasto-inertial migration of deformable capsules in a microchannel

Area of Science:

• Fluid dynamics
• Biophysics
• Microfluidics

Background:

• Understanding cell dynamics in microfluidic channels is crucial for developing advanced cell separation and analysis techniques.
• The behavior of deformable particles in fluid flow differs significantly from rigid particles, especially in non-Newtonian fluids.

Purpose of the Study:

• To investigate the motion of deformable cells in channel flows of Newtonian and polymeric fluids.
• To analyze the influence of fluid properties, cell characteristics (deformability, elasticity, inertia, size), and rheology on cell migration.
• To evaluate the potential of polymeric fluids in enhancing inertial microfluidic device performance.

Main Methods:

• Numerical simulations of deformable cell dynamics in channel flow.
• Modeling Newtonian and polymeric fluids using constitutive equations (Oldroyd-B for constant viscosity, Giesekus for shear-thinning).
• Analysis of cell trajectories and equilibrium positions across various flow conditions and fluid types.

Main Results:

• Deformable cells migrate to the channel diagonal, unlike rigid particles which move to channel faces.
• Constant-viscosity (Oldroyd-B) fluids drive cells to the centerline.
• Shear-thinning (Giesekus) fluids push cells towards the channel walls.

Conclusions:

• Polymeric fluid rheology significantly controls deformable cell migration in microchannels.
• Tuning fluid properties offers a low-cost method to enhance cell focusing and separation in microfluidic devices.
• This study provides insights for optimizing microfluidic device design through fluid manipulation.