Particle Separation in Microfluidic Channels Using Flow Rate Control

Microfluidic devices for particle recovery are successfully developed by controlling flow rate ratios of two daughter channels. Devices are prepared by using conventional Polydimethylsiloxane (PDMS) replica molding technique. The flow rate ratios of two daughter channels are controlled by changing the flow resistance through changing the geometry of the downstream channels. The particle recovery studies are conducted using 16 μm-diameter green fluorescent particles and using 8–10 μm-diameter human C8161 melanoma cells. For the fluorescent particles, the particle recovery efficiencies are 87.2%, 95.7%, 100%, and 100% for 2.5:1, 4:1, 6:1, and 8:1 flow rate ratios, respectively. Also, for the human C8161 melanoma cells, the cell recovery efficiencies are 88.7%, 98.9%, 100%, and 100% for 2.5:1, 4:1, 6:1, and 8:1 flow rate ratios, respectively.