High-throughput microparticle separation using gradient traveling wave dielectrophoresis

This paper describes highly efficient and high-throughput microparticle separation using gradient traveling wave dielectrophoresis (TwDEP) with a multilayered microelectrode design. Although cell separation based on dielectrophoresis is a very useful and versatile method, its throughput is less than that of a commercially available magnetic activated cell sorter (MACS). Further, in TwDEP-based cell sorters, the microdevices must have a large area to achieve high-throughput separation. However, increasing the TwDEP device area, which is critical for achieving throughput, has limitations: the resistance of microelectrodes also increases. In this study, we have successfully developed a novel gradient TwDEP chip with an extremely large area (31 x 25 mm(2)) using a unique multilayered bus bar design. The proposed bus bar design, which divides four ac input signals into two groups (0 degrees and 270 degrees phases and 90 degrees and 180 degrees phases), makes it possible to maintain low resistance in microelectrodes for TwDEP despite the increase in the device area. In addition, a microelectrode track design with gradually increasing gaps from 10 to 40 mu m between the electrodes was introduced; as a result, the TwDEP force and negative DEP force that balance the gravitational force decrease gradually along the microelectrode track. Finally, the microparticles could be trapped at specific locations depending on their physical properties. We demonstrated the feasibility of our suggestion using latex microparticles (3 mu m, 6 mu m, 10 mu m and 20 mu m) and showed the potential of high-throughput separation with the TwDEP technique.