Integrated siphon-based metering and sedimentation of whole blood on a hydrophilic lab-on-a-disk.

In this paper, we present a novel and fully integrated centrifugal microfluidic "lab-on-a-disk" for rapid colorimetric assays in human whole blood. All essential steps comprising blood sampling, metering, plasma extraction and the final optical detection are conducted within t=150 s in passive, globally hydrophilized structures which obviate the need for intricate local hydrophobic surface patterning. Our technology features a plasma extraction structure (V=500 nL, CV<5%) where the purified plasma (cRBC<0.11%) is centrifugally separated, metered by an overflow and subsequently extracted by a siphon-based principle through a hydrophilic extraction channel into the detection chamber.