High-throughput electrokinetic bioparticle focusing based on a travelling-wave dielectrophoretic field

Abstract

This study presents a sheathless and portable microfluidic chip that is capable of high-throughput focusing bioparticles based on 3D travelling-wave dielectrophoresis (twDEP). High-throughput focusing is achieved by sustaining a centralized twDEP field normal to the continuous through-flow direction. Two twDEP electrode arrays are formed from upper and lower walls of the microchannel and extend to its center, which induce twDEP forces to provide the lateral displacements in two directions for focusing the bioparticles. Bioparticles can be focused to the center of the microchannel effectively by twDEP conveyance when the characteristic time due to twDEP conveying in the y direction is shorter than the residence time of the particles within twDEP electrode array. Red blood cells can be effectively focused into a narrow particle stream (*10 lm) below a critical flow rate of 10 ll/min (linear flow velocity *5 mm/s), when under a voltage of 14 V p-p at a frequency of 500 kHz is applied. Approximately 90% focusing efficiency for red blood cells can be achieved within two 6-mm-long electrode arrays when the flow rate is below 12 ll/min. Blood cells and Candida cells were also focused and sorted successfully based on their different twDEP mobilities. Compared to conventional 3D-paired DEP focusing, velocity is enhanced nearly four folds of magnitude. 3D twDEP provides the lateral displacements of particles and long residence time for migrating particles in a high-speed continuous flow, which breaks through the limitation of many electrokinetic cell manipulation techniques.

The potential of a dielectrophoresis activated cell sorter (DACS) as a next generation cell sorter

“…They achieved striking results, with a recovery rate of over 98 %. On the other hand, Gupta et al developed a device named ApoStream ® to separate circulating tumor cells (CTCs) from normal and healthy blood cells in a microfluidic flow [47,51]. They not only separated various CTCs (e.g.…”

“…3, 6, 10 and 20 μm) successfully. In order to break through the limitations of conventional DACSes, Cheng et al [47] proposed a transformed cell sorting device employing two different electrode arrays that generated TwDEP force, as shown in Fig. 4.…”

Dielectrophoretic monitoring of microorganisms in environmental applications

“…Cheng and coworkers designed another version of their microfluidic integrated chip coupling travelling wave [142]. The device consisted of a microchannel 500-mm wide and 35-mm tall containing two 6-mm-long traveling wave DEP (twDEP) electrode arrays from the upper and the lower walls of the microchannel for particle focusing.…”

A Tunable Microfluidic Device for Drug Delivery

“…DEP is an efficient nondestructive way to manipulate bioparticles (Cheng et al, 2011), and twDEP is being investigated as a possible drug delivery technique (Bunthawin et al, 2010). The electrode configuration consists of an array of parallel rectangular electrodes configured in an intercalated pattern as shown in Figure 1(ib).…”