Biomimetic Design of a Microfluidic Device for Auto-separation of Leukocytes from Whole Blood

An important application of microanalytical lab-on-achip devices is the analysis of leukocytes or their genetic material, for which these cells must first be isolated from the whole blood sample. We created a simple microfluidic device that takes advantage of the intrinsic features of blood flow in the microcirculation, such as plasma skimming and leukocyte margination, to separate leukocytes directly from whole blood. It operates on microliter samples of whole blood, provides positive, continuous flow selection of leukocytes and requires no preliminary labeling of cells. A single pass through the device produces a 34-fold enrichment of the leukocyte-to-erythrocyte ratio. This effortless, efficient and inexpensive technology can be used as a lab-on-a-chip component for initial whole blood sample preparation. Its integration into microanalytical devices that require leukocyte enrichment will enable accelerated transition of these devices into the field for point-of-care clinical testing.