ECIS® uses a small non-invasive alternating current (I) that is applied across the electrode pattern at the bottom of the ECIS arrays. This results in a potential (V) across the electrodes which is measured by the ECIS instrument. The impedance (Z) is determined by Ohm’s law Z = V/I.
When cells are added to the ECIS Arrays and attach to the electrodes, they act as insulators increasing the impedance. As cells grow and cover the electrodes, the current is impeded in a manner related to the number of cells covering the electrode, the morphology of the cells and the nature of the cell attachment. When cells are stimulated to change their function, the accompanying changes in cell morphology alter the impedance. The data generated is impedance versus time.
ECIS can study cell behaviours in tissue culture. These include monolayer barrier function, cell growth rates and viability, wound-healing migration and other behaviour directed by the cell’s cytoskeleton. The ECIS® approach has been applied to numerous investigations including measurements of endothelial monolayer permeability, in vitro toxicity testing as an alternative to animal testing, the invasive nature of cancer cells, and signal transduction involving GPCR’s for modern drug discovery.
