High-Speed Single-Cell Dielectric Spectroscopy

Abstract

Single cell impedance cytometry is a label free analysis technique that is now widely used to measure the electrical properties of cell, and to differentiate different subpopulations. Current techniques are limited to measuring the impedance of a single cell at one or two simultaneous frequencies. Also there are no methods that extrapolate the intrinsic electrical properties of single cells. We demonstrate a new approach that uses multi-frequency impedance measurements to determine the complete intrinsic electrical properties of thousands of single cells at high throughput. The applicability of the method is demonstrated by measuring the properties of red blood cells and red cell ghosts, deriving the unique values of conductivity and permittivity of the membrane and cytoplasm for each individual cell.

A fast impedance-based antimicrobial susceptibility test

“…Micron-sized polystyrene beads are added to every sample as reference particles. These beads have well defined electrical properties (and size), and are used to eliminate device to device variation and non-linearities in the measurement electronics 38 .…”

Positional dependence of particles and cells in microfluidic electrical impedance flow cytometry: origin, challenges and opportunities

“…Such modeling can be used to analyze experimental data and determine the value of the different (bio)particle parameters through a fitting algorithm 56 .…”

“…In a recently developed device for single-cell dielectric characterization at high-throughput, Spencer and Morgan improved the classical facing electrodes configuration to address this issue (Fig. 13) 56 . The electric field distribution has been modified by means of grounded electrodes, resulting in a decrease of the signal variation between center and off-center particles.…”

“…2 and 3, the variation of the impedance signal as a function of cell trajectory is highly dependent on the design of the sensing zone, and can be the cause of sorting errors and of unexpected spreads in cell populations extracted features. So far, this impact on measurements has mostly been highlighted in the standard coplanar and facing electrode configurations 34,39,56,133,137 . However, the positional dependence is not restricted to those configurations.…”

Electrical Impedance Spectroscopy for Monitoring Chemoresistance of Cancer Cells

“…Fluid flow is incorporated in IFC setups to measure the impedance of cells flowing pass electrodes. The electrodes are planar and located on the bottom of the microchannel [ 45 ] or integrated on the top and bottom of the microchannel to extend the height of the electric field increasing sensitivity [ 46 , 47 ]. Additionally, IFC systems may include a constriction in the microchannel, where the cross-sectional area is less than the cell’s cross-sectional area, to further improve detection capability of single cells [ 48 ].…”