Passage times and friction due to flow of confined cancer cells, drops, and deformable particles in a microfluidic channel

The confined flow of cancer cells, viscous droplets, and deformable, elastic particles in microchannels at millisecond deformation timescales show that the passage time and friction force depend on cell, droplet, and particle size and viscosity of the emulsion droplets, but not on the elastic modulus of particles, contrary to prior claims. Force balance reveals a viscosity-dependent lubrication film thickness larger than 100 nm in the majority of cases, indicating that hydrodynamic friction and not surface friction dominates cell and deformable particle transport. Our results suggest that—in the hydrodynamic friction regime—cancer cell transport through microchannels is similar to that of drops. Given that prior works report passage times and cell velocities that vary by five orders of magnitude, we emphasize the need to comprehensively understand the relationship between cell confinement, velocity, friction force, lubrication film thickness, and rheology to interpret tumor cell passage time data and connect it to cancer cell invasiveness. PAPER 2017