Dielectrophoretic-activated cell sorter based on curved microelectrodes

Abstract

This article presents the numerical and experimental analysis of a dielectrophoretic-activated cell sorter (DACS), which is equipped with curved microelectrodes. Curved microelectrodes offer unique advantages, since they create strong dielectrophoretic (DEP) forces over the tips and maintain it over a large portion of their structure, as predicted by simulations. The performance of the system is assessed using yeast (Saccharomyces cerevisiae) cells as model organisms. The separation of the live and dead cells is demonstrated at different medium conductivities of 0.001 and 0.14 S/m, and the sorting performance was assessed using a second array of microelectrodes patterned downstream the microchannel. Further, microscopic cell counting analysis reveals that a single pass through the system yields a separating efficiency of *80% at low medium conductivities and *85% at high medium conductivities.

Dielectrophoresis in microfluidics technology

“…This unique dielectric signature can be utilized to discriminate and identify cells from the other particles or to detect and isolate diseased or damaged cells by means of AC-DEP (DEP force spectra of different cell types can be found elsewhere [118,144]). AC-DEP has been implemented for the separation of cancer cells from blood stream [17,18], the separation of red blood cells and polystyrene particles [19], the separation of human leukocytes [20], the isolation of the malaria-infected cells from the blood [21,22], the separation of the electroporated and non-electroporated cells [23], the separation of the platelets from diluted whole blood [24], the separation of red blood cells and the white blood cells [25], the separation [26][27][28] and sorting [29] of viable and nonviable yeast cells, the separation of healthy and unhealthy oocyte cells [30], the characterization and the sorting stem cells and their differentiated progeny [31], the isolation of rare cells from biological fluids [32], the separation of three distinct bacterial clones of commonly used E. coli MC1061 strain [33], trapping of viable mammalian fibroplast cells [34], trapping of DNA molecules [35], trapping of single cancer and endothelial cells to investigate pairwise cell interactions [36], trapping of bacterial cells for the subsequent electrodisruption or electroporation [37], focusing of polystyrene particles [38], trapping of yeast cells [39], 3-D focusing of polystyrene particles and yeast cells [40], the separation of airborne bacterium, Micrococcus luteus, from a mixture with dust and polystyrene beads [41], trapping and isolation of human stem cell from heterogeneous solution [42], single-cell isolation [43], concentration and counting of polystyrene particles [44], the separation of polystyrene particles, Jurkat cells and HeLa cells …”

Numerical Comparison between Nonisolated and Isolated Metal-Electrode-Based Dielectrophoresis Cell Separation

“…In most electrode-based DEP devices, various structures of coplanar metal electrodes are devised at the bottom of the microchannel to create a nonuniform electric field, e.g., interdigitated, (9,10) castellated, (11,12) curved (13,14) and polynomial. (15) Metal electrodes are made of precious metals usually requiring multilevel deposition processes; in most cases, electrodes are made from chromium/gold, (16) titanium/gold (17) and titanium/platinum.…”

Circulating tumor-cell detection and capture using microfluidic devices

“…If the cell is more polarizable than the suspending medium, it is attracted towards the regions of higher electric fields, and the motion is called positive DEP. Conversely, if the cell is less polarizable than the suspending medium, it is repelled from the regions of higher electric field, and the motion is called negative DEP [50,51].…”