Label-Free Analysis

CellKey System Technology: Impedance-Based Label-Free Measurement

Cellular Dielectric Spectroscopy (CDS) is a label-free technology based on the measurement of complex impedance changes (delta Z , or dZ). Impedance (Z) is related to the ratio of voltage to current as described by Ohm's law (Z = V/I).

In order to measure the changes in impedance that occur in response to receptor stimulation, mammalian cells are seeded onto a custom microtiter plate that contains electrodes at the bottom of each well. The CellKey® System supplies a constant voltage, producing a current that at low frequencies flows both around and between cells (extracellular current, Ziec) and at high frequencies through cells (transcellular current, Zitc).  

     Impedance measurement

Play Video View an animated overview of the CellKey technology.


Key contributors to the impedance measurements are changes in cell-substrate adherence, changes in cell shape and volume, and changes in cell-cell interactions. These factors individually or collectively affect the flow of extracellular and transcellular current, influencing the magnitude and characteristics of the signal measured.

Activation of cell receptors results in characteristic bioimpedance measurements, indicative of the signaling pathway being activated and unique to the main subsets of G-protein coupled receptors (GPCRs) and tyrosine kinase receptors (TKRs), among others.