Polarizability-Dependent Sorting of Microparticles Using Continuous-Flow Dielectrophoretic Chromatography with a Frequency Modulation Method

Abstract

The separation of microparticles with respect to different properties such as size and material is a research field of great interest. Dielectrophoresis, a phenomenon that is capable of addressing multiple particle properties at once, can be used to perform a chromatographic separation. However, the selectivity of current dielectrophoretic particle chromatography (DPC) techniques is limited. Here, we show a new approach for DPC based on differences in the dielectrophoretic mobilities and the crossover frequencies of polystyrene particles. Both differences are addressed by modulating the frequency of the electric field to generate positive and negative dielectrophoretic movement to achieve multiple trap-and-release cycles of the particles. A chromatographic separation of different particle sizes revealed the voltage dependency of this method. Additionally, we showed the frequency bandwidth influence on separation using one example. The DPC method developed was tested with model particles, but offers possibilities to separate a broad range of plastic and metal microparticles or cells and to overcome currently existing limitations in selectivity.

High‐throughput dielectrophoretic separator based on printed circuit boards

“…Particles experiencing nDEP, in contrast, will be repelled from them and are continuously flushed out of the channel (Figure 1C). This electrode configuration differs from traditional DEP-FFF setups where electrodes at the bottom of the device are used to levitate particles on specific flow lines to achieve characteristic retention time [26,51,52] or guide them into specific outlets [53]. In DEP-FFF setups, the drag force does not compete with the dielectrophoretic force.…”

Material- and Size-selective Separation Mechanism of Micro Particles in Frequency-modulated Dielectrophoretic Particle Chromatography

“…The microfluidic device has been described in detail in a previous publication 33 . Briefly, the h = 80 µm high microfluidic channel is made out of PDMS, has a width of 2 mm and a length of about 17 cm.…”

“…27 numerically showed the benefit of multiple trap-and-release cycles in DPC. In a previous publication, we demonstrated the capabilities of a design that combined multiple trap-and-release cycles with the advantage of changing the frequency 33 . The chromatographic separation allows to address particle mixtures with only small dielectric differences or distributed particle properties.…”

High-Sensitivity in Dielectrophoresis Separations

“…In the combined-field separation area, work by Urdaneta and Smela showed separation of live and dead yeast cells, using different frequencies to preferentially attract each cell type to a different set of electrodes [31]. Similar techniques have been recently applied, taking advantage of multi-frequency signals (amplitude, frequency, or phase modulated) on a single electrode array to generate dissimilar DEP actuation forces on particles of interest to separate polystyrene microspheres based on size [32], algae cells based on lipid content [33], and MCF7 cancer cells from diluted blood [34]. Planar multifield configurations have also been extended to concentrate viruses, proteins, and bacteria [35].…”