DC-Dielectrophoretic Manipulation and Isolation of Microplastic Particle-Treated Microalgae Cells in Asymmetric-Orifice-Based Microfluidic Chip

Abstract

A novel direct-current dielectrophoretic (DC–DEP) method is proposed for the manipulation and isolation of microplastic particle (MP)-treated microalgae cells according to their dielectric properties in a microfluidic chip. The lateral migration and trajectory of the microalgae cells were investigated. To induce stronger DC–DEP effects, a non-homogeneous electric-field gradient was generated by applying the DC electric voltages through triple pairs of asymmetric orifices with three small orifices and one large orifice located on the opposite microchannel wall across the whole channel, leading to the enhanced magnitude of the non-uniform electric-field gradient and effective dielectrophoretic area. The effects of the applied voltage, the polystyrene (PS) adsorption coverage, and thickness on the DC–DEP behaviors and migration were numerically investigated, and it was found that the effect of the PS adsorption thickness of the Chlorella cells on the DC–DEP behaviors can be neglected, but the effect on their trajectory shifts cannot. In this way, the separation of 3 µm and 6 µm Chlorella coated with 100% PS particles and the isolation of the Chlorella cells from those coated with various coverages and thicknesses of PS particles was successfully achieved, providing a promising method for the isolation of microalgae cells and the removal of undesired cells from a target suspension.

Impact of Processing Parameters on Contactless EmulsificationviaCorona Discharge

“…, a large potential gradient), which always attracts the droplets in the direction of the strongest pole of the field. 75 , 76 In this study, the strongest pole is the discharging needle, and the direction of the droplet elongation is always upward (due to the DEP forces), regardless of the direction of the electric field (in the case of using an AC field). As a result, depending on the conditions in the discharge zone ( i.e.…”

“…As this process continues, the elongation causes necking and pinch-off in the deformed droplets. , On the other hand, the DEP forces occur due to a significant difference in potential between the two poles ( i.e. , a large potential gradient), which always attracts the droplets in the direction of the strongest pole of the field. , In this study, the strongest pole is the discharging needle, and the direction of the droplet elongation is always upward (due to the DEP forces), regardless of the direction of the electric field (in the case of using an AC field). As a result, depending on the conditions in the discharge zone ( i.e.…”

“…73,74 On the other hand, the DEP forces occur due to a significant difference in potential between the two poles (i.e., a large potential gradient), which always attracts the droplets in the direction of the strongest pole of the field. 75,76 In this study, the strongest pole is the discharging needle, and the direction of the droplet elongation is always upward (due to the DEP forces), regardless of the direction of the electric field (in the case of using an AC field). As a result, depending on the conditions in the discharge zone (i.e., oil viscosity, fluid circulation velocity, and number of already diffused water droplets), either of these forces can act to deteriorate the quality of the emulsions with coalescence and enlargement of the water droplets.…”

High-throughput separation of microalgae on a runway-shaped channel with ordered semicircular micro-obstacles

“…Microfluidic separation is mainly categorized into active and passive approaches [6]. Active techniques utilize external fields (electrics [7], magnetics [8], acoustics [9], etc.) to facilitate particle/cell separation.…”

Design of a Low-Frequency Dielectrophoresis-Based Arc Microfluidic Chip for Multigroup Cell Sorting

“…Different structures of electrodes and channels are designed to perform different functions. Tianbo Gao et al [ 19 ] proposed a novel design of a DC dielectrophoresis microfluidic chip with rectangular electrodes placed on one side of the channel horizontally and electrodes with rectangular teeth on the other side, and successfully separated Chlorella vulgaris coated with 100% PS particles at 3 μm and 6 μm. Pouya Sharbati et al [ 20 ] proposed a novel microfluidic device that successfully isolated four types of cells, red blood cells, T-cells, U937-MC cells and Clostridium difficile bacteria, simultaneously by using two sets of electrodes, a cylindrical electrode and a sidewall rectangular electrode.…”