The Physical Origins of Cell Transit through Microfluidic Constrictions

Abstract

Altered cell mechanical properties are implemented in a range of physiological processes, such as stem cell differentiation and cancer. Methods to measure the mechanical properties of single cells are integral to advancing our understanding of these processes. One such technique tracks the deformation and speed of cells as they flow through micron-scale constrictions of a microfluidic device; however, the physical origins of the timescale for cells to deform through narrow pores remain poorly understood. By fabricating soft microparticles with distinct mechanical properties, we show that deformation times strongly depend on elastic modulus and viscosity, and weakly depend on surface tension and size. Higher resolution tracking of gel particle and oil droplet deformations reveals power-law behavior; we also observe this behavior in the deformation of HL-60 cells. While various physical models have been used to interpret results from similar microfluidic assays, our results indicate that the viscous and elastic properties of materials modulate deformation timescales through micron-scale constrictions, and that power law rheology may provide valuable insight into cell deformability studies using this technique.