Particle Separation in Microfluidic Devices — SPLITT Fractionation and Microfluidics

In recent years, microfluidic devices have been increasingly used to separate particles such as colloids, macromolecules, cells, beads and droplets. Miniaturisation often introduces new functionalities and paradigms that are not possible at conventional macroscopic scales. In this paper, split-flow-thin fractionation techniques for particle separation are reviewed and the underlying physics of particle migration is discussed. The potential of these particle separation techniques in the design of integrated microfluidic systems is described. We then illustrate how numerical simulation can provide an increased understanding of the fluid-particle motion. The advantages of numerical simulation for rational design and operation of microfluidic devices are highlighted through two practical examples involving an ultrasonic cell washing system and a quadrupole magnetic flow sorter.