What is the future of electrical impedance spectroscopy in flow cytometry?

What is it about?

Flow cytometry (FC) is the laboratory standard to detect and assess the properties of cells. The most common way to do it is via fluorescence-activated cell sorting (FACS), where the cells are labeled with fluorescence markers and flown through a set of lasers and detectors to excite and record the fluorescent signals. This method requires expensive set-ups and educated operators to conduct analyses. In comparison, electrical impedance spectroscopy (EIS) was proposed two decades ago as a label-free alternative to FACS-FC for assessing the cells without the need for expensive equipment or operators. In EIS-FC, cells are suspended in an electrolyte and flown through a set of electrodes that record the impedance at different electrical frequencies to probe the dielectric properties of the cells that are between the electrodes. In this perspective, we discuss the current status of flow cytometry techniques, and compare EIS-FC with FACS-FC in today's conditions, instead of that two decades ago. In addition, we also elaborate on the promises of EIS-FC when compared with today's FACS-FC and image-activated cell sorting (IACS-FC), for the first time in the literature. We then conclude with some possible prospects of EIS in flow cytometry.

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Photo by Javier Allegue Barros on Unsplash

Photo by Javier Allegue Barros on Unsplash

Why is it important?

This perspective reviews impedance-based cytometry (EIS-FC), by revisiting the initial promises of EIS-FC when it was proposed for the first time more than two decades ago, and it evaluates those promises in today's conditions in comparison to FACS-FC.