Centrifugal Separation Device Based on Two-Layer Laminar Flow in Microchannels for High-Throughput and Continuous Blood Cell/Plasma Separation

Abstract

This paper presents a novel type of centrifugation device that is based on the two-layer laminar flow in micro flow channels for continuous blood cell/plasma separation. We propose to rotate the flow channels which are arranged along the circumference around the rotational axis. Downsizing the channel width reduced both the cell sedimentation time and the required centrifugal force, because the channel width corresponds to the centrifugal sedimentation length. First, plasma and cells were continuously extracted from pig blood in each of the branch channels using a milled acrylic prototype device (channel width = 800 µm, volume = 150 µl). Next, the relationship between the channel width (125, 250, and 500 µm) and the sedimentation time taken for various centrifugal forces (2.3, 9, 36, and 145 G) was evaluated using the downsized microchannels fabricated by hot-embossing and thermal bonding technologies. Using downsized microchannels with a width of 125 µm successfully reduced the sedimentation time to 85 s as compared to the sedimentation time of 270 s for a channel of a width of 500 µm, when a centrifugal force of 2.3 G was applied. The use of the proposed device did not result in obvious hemolysis at the centrifugal forces lower than 335 G.

Blood typing chip using human whole blood sample

“…Using a syringe pump, the 3% diluted whole blood is injected into the inlet (A) and flows through the separation microchannels. Since plasma has less mass than blood cells, the centrifugal force produced in the curved separation microchannel results in blood cell flow and plasma flow as a double‐layer laminar flow [16, 17]. Then, the blood plasma is drawn out and collected in the plasma chamber (B), whereas erythrocytes and leucocytes are driven forward to the microfilters.…”

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Microfluidic chip for plasma separation from undiluted human whole blood samples using low voltage contactless dielectrophoresis and capillary force

“…Many microfluidic devices for plasma separation from whole blood samples have already been developed. Most methods used centrifugal force, 1,2 and the red blood cells, white blood cells, and platelets were captured using microfilters. 3,4 Changing the geometry of a microchannel allows different forces to be created in the channel for separation.…”