Fig. 2

Schematic diagram of the microfluidic device. a 3D and (b) 2D schematics of the operation principle using driving pressure by centrifugal force, ΔPd, or vacuum-driven pressure, Pv. The centrifugal pressure allowed the sample to be driven in a one-way direction, while the vacuum-driven force could be used in various directions to drag the sample without any rotation. c Comparison between the centrifugal flow and the vacuum-driven flow in each dead-end and open-end channel. The centrifugal pressure required an open-end channel to drive a sample, while the vacuum-driven pressure required a dead-end channel to drive a sample [29]