Sequential Cell-Processing System by Integrating Hydrodynamic Purification and Dielectrophoretic Trapping for Analyses of Suspended Cancer Cells

Abstract

Microfluidic devices employing dielectrophoresis (DEP) have been widely studied and applied in the manipulation and analysis of single cells. However, several pre-processing steps, such as the preparation of purified target samples and buffer exchanges, are necessary to utilize DEP forces for suspended cell samples. In this paper, a sequential cell-processing device, which is composed of pre-processing modules that employ deterministic lateral displacement (DLD) and a single-cell trapping device employing an electroactive microwell array (EMA), is proposed to perform the medium exchange followed by arraying single cells sequentially using DEP. Two original microfluidic devices were efficiently integrated by using the interconnecting substrate containing rubber gaskets that tightly connect the inlet and outlet of each device. Prostate cancer cells (PC3) suspended in phosphate-buffered saline buffer mixed with microbeads were separated and then resuspended into the DEP buffer in the integrated system. Thereafter, purified PC3 cells were trapped in a microwell array by using the positive DEP force. The achieved separation and trapping efficiencies exceeded 94% and 93%, respectively, when using the integrated processing system. This study demonstrates an integrated microfluidic device by processing suspended cell samples, without the requirement of complex preparation steps.

Fabrication of a new all-in-one microfluidic dielectrophoresis integrated chip and living cell separation

“…Cell are separated by slanted electrodes Possible continuous separation Samples need to be preadjusted to constant conductivity. Separation by size cannot be performed Park et al. (2019) Not required Yes (DEP-DLD) Not required Microwell array No by batch Separation with DEP array after adjusting the conductivity in the chip Not requiring buffer exchange and size separation Continuous separation cannot be performed This study (2021) Not required Yes (DEP-HDF) Not required Slanted (pDEP) Yes Continuous separation with slanted electrodes after adjusting the conductivity in the chip Not requiring buffer exchange and continuous size separation Sample throughput need to be improved.…”

“…Because the device is a label-free and one-step operation, cell damage during the operation is minimized. Our device is similar to what Park et al. (2019) introduced, a microfluidic DEP capable of replacing buffer by an integrated DLD (deterministic lateral displacement) module.…”

“…The two devices differ in cell sorting systems, “batch” or “continuous” separation ( Hughes, 2016 ). The device by Park et al. (2019) uses the former, where positive DEP traps one cell type while the other is repelled and collected, requiring a second step to recover the trapped cells ( Hughes, 2016 ).…”

The Fabrication and Application Mechanism of Microfluidic Systems for High Throughput Biomedical Screening: A Review

“…The separation target is not limited to cells, but can also be applied to purifying nano-scale virus, nanoparticles, DNA, and so on [88]. Park et al utilized dielectrophoresis to manufacture single-cell traps in a microfluidic chip for the analysis of suspended cancer cells [89]. Sun et al pre-created patterned dielectrophoretic force in a microfluidic device to direct cells into a capture zone.…”

Single-Cell Microarray Chip with Inverse-Tapered Wells to Maintain High Ratio of Cell Trapping

“…Dielectrophoresis (DEP) utilizes the dielectric properties of cells to trap them. Electrodes are placed on one or both sides of a flow channel; cells are passed through the nonuniform electric field, which manipulates the charged cells and separates and traps them at the designated position (s) [ 18 , 19 , 20 ]. DEP also has high-resolution cell manipulation performance; however, specialized knowledge and complex equipment are required for a well-balanced set up, considering the fluid, electrical, and gravitational forces.…”