Separation enhancement in pinched flow fractionation

A method for enhancing the separation in the microfluidic size separation technique called pinched flow fractionation (PFF) is demonstrated experimentally and analyzed by numerical calculations. The enhancement is caused by a geometrical modification of the original PFF design. Seven different polystyrene bead sizes ranging from 0.25 to 2.5 mu m in radius were separated in a PFF and in an enhanced PFF device. The separation in the two types of devices were compared and an amplification in the separation of up to 70% was achieved. Numerical calculations, which include an edge effect, are used to analyze the device.