A novel passive microfluidic device for preprocessing whole blood for point of care diagnostics

A novel strategy to sort the cells of interest (White Blood Cells (leukocytes)) by selectively lysing the Red Blood Cells (erythrocytes) in a miniaturized microfluidic device is presented. Various methods to lyse cells on a chip exist i.e. electrical, mechanical, chemical and thermal but they need integration of electrodes, traps, reservoirs, heaters, etc which is often difficult at microscale. On the other hand, FACSlyse protocol uses only osmotic pressure to lyse erythrocytes allowing further isolation of leukocytes. This motivated us to develop a novel herringbone based lyser which works on the principle of mixing whole blood with pure water in time controlled manner to lyse erythrocytes osmotically on a chip.