Cell trapping utilizing insulator-based dielectrophoresis in the open-top microchannels

Abstract

Cell Trapping Utilizing Insulator-based Dielectrophoresis in The Open-Top Microchannels(1) II. DIELECTROPHORETIC(DEP) FORCE THEORYThe phenomenon ofDEP is first defined by Pohl (1978) as the motion of neutral particles caused by dielectric polarization effects in non-uniform electric fields that alternating fields of a wide range of frequencies were used. The DEP force F DEP acting on a spherical particle of radius r suspended in a fluid of permittivity Em is given:) application to automation because DEP traps consist of scalable electrode arrays be designed to pattern thousands of cells on a single glass slide. DEP have been using as cell trapping [13], levitation [14], separation [15], and sorting [16] on an electrode array by varying electrode shape and arrangement. DEP on micro-fabricated electrodes has been proved especially suitable for its relative ease of micro-scale generation and structuring of an electric field on microchips.DEP force field could also be generated by using dielectric constrictions or insulating obstacles, therefore, these methods further extend the scope of DEP applications. These approaches have been termed electrodeless dielectrophoresis (EDEP) [17] or insulator-based dielectrophoresis (iDEP) [18], respectively, in distinguishing from the method conventionally employed by metal electrodes-based DEP for force generation.In this study, a lower conductive material of photoresist (JSR, THB I5IN) was adopted as a structure in open-top microchannel instead ofa metallic wire to squeeze the electric field in a conducting solution, therefore, creating a high field gradient with a local maximum. The microchip with the open-top microchannels was designed and fabricated herein. The schematic illustration of the trapping device is shown in Fig 1. This trapping microchip is suitable for trapping cells or biological samples and easily proceeding further treatment for cells, such as culturing or contact detection. Biological sample and buffer loading before analysis and cleaning after analysis in the proposed microchip with the open-top microchannels could become easier and faster, hence, it is beneficial in high-speed sequential multiple measurements. Furthermore, the Joule heat generated by applying high voltage in the open-top microchannel could dissipate more effectively than that in the enclosed microchannel, because that it is open to the air. When the fluorescent detection is used, the intensity ofthe emitted light will not be interfered by the cover, which is absent in the microchip with open-top microchannels.

Direct current insulator‐based dielectrophoretic characterization of erythrocytes: ABO‐Rh human blood typing

“…While DC-iDEP has been utilized for separation and trapping of human cells [29][30][31], the application of DC-iDEP for manipulating erythrocytes remains unexplored. This investigation into erythrocyte iDEP builds from our prior findings that ABO expression alters erythrocyte polarizations to yield discernibly unique motion along an AC electric field gradient; the system was capable of ascertaining ABO blood type in o5 min [1].…”