Rutherford device to measure deformability of red blood cells*

Red blood cells (RBCs) lose their deformability in response to many environmental and physiological cues. We present a simple microfluidic device, consisting of a channel that opens up to a funnel behind a  single obstacle. By tracking the trajectories of single RBCs after they pass the obstacle we are able  to measure their Young’s modulus.  Softer RBCs and stiffer RBCs emerge along different streamlines in our device. We calibrate the trajectories of healthy and artificially stiffened RBCs in this microfluidic device against the Young’s moduli obtained from AFM measurements of these RBCs. Further, we demonstrated that healthy and malaria-infected RBCs follow different trajectories in our device.