Continuous blood separation utilizing spiral filtration microchannel with gradually varied width and micro-pillar array

A microfluidic separation device that uses the cross flow and the centrifugation effect to separate human plasma from whole blood has been designed, fabricated and evaluated. The chip mainly consists of a spiral channel divided into inner and outer microchannels by micropillar arrays, which are employed to filter blood cells and plasma. The major feature of this chip is that the width of the inner channel decreases gradually from the inlet to the outlet in order to increase the separation efficiency. Clogging and jamming in this filtration structure are efficiently alleviated. The performances of the separation device have been investigated theoretically and experimentally. Due to high purity of plasma and compact structure, this device can be used as either a plasma extraction device solely, or a pretreatment component that is integrated with other microfluidic device for point-of-care diagnostics.