Continuous On-Chip Cell Separation Based on Conductivity-Induced Dielectrophoresis with 3D Self-Assembled Ionic Liquid Electrodes

Abstract

Dielectrophoresis (DEP) has been widely explored to separate cells for various applications. However, existing DEP devices are limited by the high cost associated with the use of noble metal electrodes, the need of high-voltage electric field, and/or discontinuous separation (particularly for devices without metal electrodes). We developed a DEP device with liquid electrodes, which can be used to continuously separate different types of cells or particles based on positive DEP. The device is made of polydimethylsiloxane (PDMS) and ionic liquid is used to form the liquid electrodes, which has the advantages of low cost and easy fabrication. Moreover, the conductivity gradient is utilized to achieve the DEP-based on-chip cell separation. The device was used to separate polystyrene microbeads and PC-3 human prostate cancer cells with 94.7 and 1.2% of the cells and microbeads being deflected, respectively. This device is also capable of separating live and dead PC-3 cancer cells with 89.8 and 13.2% of the live and dead cells being deflected, respectively. Moreover, MDA-MB-231 human breast cancer cells could be separated from human adipose-derived stem cells (ADSCs) using this device with high purity (81.8 and 82.5% for the ADSC and MDA-MB-231 cells, respectively). Our data suggest the great potential of cell separation based on conductivity-induced DEP using affordable microfluidic devices with easy operation.

Review: Microbial analysis in dielectrophoretic microfluidic systems

“…However, a number of methodologies have recently emerged 199 , including those using conducting polymers 200 , silver-PDMS 201 , liquid metals 202 , screen printing 203 and vapor deposition, constructed by techniques of micromolding 204 , semiconductor fabrication 205,206,207,208,209 , and low-cost bonding methods on hybrid platforms 210,203 . The reduced dead volumes of such 3D electrode platforms have been applied to enhance the spatial extents of the field non-uniformity 211,212 to enable high throughput separations 213,214 , cytometry 215,216 , sample enrichment for biomolecular determination 217,218 , sample transport by traveling-wave dielectrophoresis 219,220,221 , and dielectric characterization of cells by electro-rotation 222,223,224 .…”

Recent advances in dielectrophoresis‐based cell viability assessment

“…(C) PC‐3 cells separated by conductivity‐induced dielectrophoresis. Adapted with permission from , © 2016 American Chemical Society. (D) Illustration of living CD45 neg /EpCAM neg cells isolation device using oDEP.…”

“…In 2016, He's group developed a novel DEP device with liquid electrodes for the separation of living/dead PC‐3 human prostate cancer cells. Ionic liquid (140 mS/m), which was immiscible with the suspending medium (10% w/v sucrose, 0.3% w/v glucose, and 0.8% v/v PBS, 14 mS/m), was used as the electrode.…”

Microfluidics cell sample preparation for analysis: Advances in efficient cell enrichment and precise single cell capture

“…Because most biological cells have dielectric characteristics in an external electric field, cells in suspension can be controlled by DEP force or torque. [70][71][72] Cells can be stimulated to travel to the region with a strong electric field by a positive DEP force in the non-uniform electric field, or conversely, to the area with a weak electric field by a negative DEP force.…”