As major players in our defense system, white blood cells (WBCs) are essential for immunological tests. However, WBCs exist at low concentration in blood samples, typically less than 0.5% of blood cells, and separation or enrichment of leukocytes is therefore a critical initial step in many biological experiments. This paper reports a novel method, based on differential inertial focusing, for separating blood cells in high throughput fashion (volumetric flow rates >2 ml/min). In this method, inherent hydrodynamic forces developed in flow through curved channels force cells to migrate over streamlines and focus laterally in equilibrium positions based on size.
