Cell deformation in a cross-channel: integration of computational modeling with DC experiment
Cell deformability is being recognized as an easily measurable indicator to differentiate different types of cells and detect diseased cells. A recent promising and advantageous technique to assess cell deformability is the cross-channel microfluidic deformability cytometry (DC). It uses a stretching extensional flow, in which each time an individual cell undergoes deformation. Using our three-dimensional computational algorithm for multiphase viscoelastic flow, known as VECAM, this study focuses on modeling the deformation of living cells in such microfluidic channels. Through the computational simulations, we first identified the central extensional flow region in the cross section of the channel, where cells are stretched due to mostly fluid momentum and resulting normal stresses. Our simulation data indicate that the range of deformability indices observed for human cells in DC experiments (from 1.5 to 2.3) corresponds to the range of cell elasticities from 3,000 to 15,000 Pa. We have also showed that both cell size and cortical tension have a much less effect on cell deformability than cell elasticity. The study further shows the cell oscillation in the extensional flow region caused by pressure imbalance in DC experiments does not affect much how long cell stays in this region and has a very limited impact on the measured cell deformability index. Finally, our study shows offset in both Y and Z directions can alter the results of the deformability measurement in a significant way. Our fully three-dimensional parallel computational algorithm is proven to realistically simulate cell movement and deformation in the cross-channel deformability cytometry. With the acquired simulation results, the computational study provides helpful insights and future guidance that are otherwise impossible to be obtained from the experimental data to the cytometry experiments.