Enhanced blood plasma separation by modulation of inertial lift force

This paper describes enhanced blood plasma separation by modulating the inertial lift force for separation in a contraction–expansion array (CEA) microchannel. By changing a contraction channel length, we observed the force modulation effects for size-based particle separation. In the CEA device, there are two force components that act in opposite direction to separate particles by size. By lengthening the contraction region in the CEA microchannel, we can easily control the lateral migration of desired particles by modulating a single force component (inertial lift force) without affecting the other (Dean drag force). From the experimental results, the inertial force ratio was calculated for prediction of force superiority between inertial lift force and Dean drag force, and applied to determine design parameters of the CEA microdevice for blood plasma separation. Using the force modulation in the microchannel, we successfully demonstrated enhancement of inertial blood plasma separation from human whole blood with a substantially high blood cell rejection ratio and a separation yield of 92.6% and 69.5%, respectively, with a throughput of 5.4 × 1011 cells/min.