Electroporation of cells in microfluidic devices: a review

Abstract

In recent years, several publications on microfluidic devices have focused on the process of electroporation, which results in the poration of the biological cell membrane. The devices involved are designed for cell analysis, transfection or pasteurization. The high electric field strengths needed are induced by placing the electrodes in close proximity or by creating a constriction between the electrodes, which focuses the electric field. Detection is usually achieved through fluorescent labeling or by measuring impedance. So far, most of these devices have only concerned themselves solely with the electroporation process, but integration with separation and detection processes is expected in the near future. In particular, single-cell content analysis is expected to add further value to the concept of the microfluidic chip. Furthermore, if advanced pulse schemes are employed, such microdevices can also enhance research into intracellular electroporation.

Electroporation: an arsenal of application

“…With the integration of several steps, continuous electroporation using flow-through microchips or other microfluidic devices were reported (Lin et al 2002;Fox et al 2006). At present these electroporation devices were roughly divided into three categories: analyzing cellular properties or intracellular content, transfecting cells and inactivating cells (Fox et al 2006).…”

“…With the integration of several steps, continuous electroporation using flow-through microchips or other microfluidic devices were reported (Lin et al 2002;Fox et al 2006). At present these electroporation devices were roughly divided into three categories: analyzing cellular properties or intracellular content, transfecting cells and inactivating cells (Fox et al 2006). Chip methods help to manipulate cells in a single manner under different parameters at the same time, which makes comparison of different settings on the same chip possible; nevertheless most of the chips so far have focused on studies of the electroporation process, and the in situ detection and live screening might add further value to these devices.…”

Fast-lysis cell traps for chemical cytometry

“…14-20 Electrical lysis of cells has been accomplished on microchip devices typically using a total voltage across the electrodes from 6 V to 1.4 kV depending on the intra-electrode distance. 13,14,16,[21][22][23][24] When the electric potential of the electrodes surpasses 2.06 V, electrolysis of water occurs, resulting in the formation of gas at the electrode. 25 This gas formation can rapidly obstruct a microchannel leading to electrophoretic failure in both microfluidic and capillary-based electrophoresis.…”

Droplet microfluidic platform for cell electrofusion

“…When subjected to an electric field, dielectric particles such as cells, experience a range of electrokinetic forces, pressures and torques 50 . An external electric field can induce formation of pores in cell membranes, move cells by DEP and fuse membranes 51 .…”

“…With positive DEP the cells align towards the region of the highest electric field, see figure 3. At higher frequencies (~1-100 MHz), the field will bridge the membrane and the CM factor will compare the permittivity of the cytoplasm and the media, resulting in negative DEP at higher solution conductivities and positive DEP at low solution conductivities 50,[58][59][60] . Finally, the application of high frequencies (>1 GHz) will result in negative DEP, likely due to cytoplasmic proteins that impart a net permittivity lower than the surrounding medium 64 .…”