Simultaneous separation, metering, and dilution of plasma from human whole blood in a microfluidic system

In about a 3 min period, we have simultaneously separated plasma from human whole blood and metered and diluted the plasma using a microchip with an interchannel microstructure. The plasma separation was based on both cross-flow filtration and sedimentation of red blood cells in the microchannels. Metering and diluting operations of the plasma were based on volume control of liquid in the microchannels by syringe pumps. On this microchip, we produced plasma diluted by a factor of 6 from whole blood containing theophylline and we observed very little hemolysis. It is possible to separate plasma from one or just several drops of whole blood by using this microchip.