Erythrocyte deformation in a microfluidic cross-slot channel†
Red blood cell (RBC) deformation is a dominant factor in the rheological properties of blood in vessels smaller than 300 micrometers. The extensional flow within a microfluidic cross-slot microchannel has been proposed as a mechanism for measuring the deformation of cells. Three-dimensional simulations of red blood cell deformation in a microfluidic cross-slot channel are presented. Simulations show that the entry position and angular orientation of cells have a significant effect on deformation, with greater deformation occurring when cells enter either near the center or close to the wall. Cells of varying stiffness are simulated to emulate the effect of pathological conditions like diabetes or malaria, and it is found that cross-slot devices can effectively differentiate between cells of varying elasticity. Necessary sample sizes to differentiate between populations of healthy and diseased cells to a statistically significant level using a Wilcoxon rank-sum test are estimated and are found to decrease with lower flow rates. The capacity of such a device to differentiate populations of healthy RBCs and malarial RBCs at statistically significant levels with sample sizes as low as fifty is demonstrated.