Glossary

Array Holder
Base & two clamps that house two arrays. When the clamps are gently screwed down, and make contact with the gold pads of the array, an AC current is able to be carried through the leads to the array, and back to the ECIS instrument.
Barrier Function
The spacing between the ventral side of the cell and the substratum, and the cell membrane capacitance
Capacitance
Combining the voltage and phase of the current allows ECIS to break impedance into two parts; resistance and reactance. The reactive part (Xc) in this case is associated with the metal surfaces in the tissue culture medium (the electrolyte). The capacitive reactance is measured in ohms depends upon the AC frequency.
Confluence
When cultured cells have created a monolayer covering the entire electrode and bottom of the well.
ECIS
Electric Cell-substrate Impedance Sensing: an automated instrument that uses AC current to monitor the behavior of cells in tissue culture, quantitatively and in real time.
ECIS cultureware
Disposable electrode arrays consisting of gold film electrodes delineated with an insulating film and mounted on a 20-mil optically clear Lexan polycarbonate substrate, all measurable with ECIS.
Electrode Array
A slide patterned with gold, and insulating film with an upper chamber assembly containing 8 wells. At the base of each well there can be any combination of electrodes. The standard electrode is 250 micrometers in diameter.
Electrolyte
Metal surfaces in the tissue culture medium.
Electroporation
A milliampere of current resulting in voltages across the cell membranes creating pores from which the cells can recover.
Impedance
A unit of measurement by applying the AC current (I) to the electrode system and measure the resulting voltage (V) across the electrodes, the impedance (Z) is simply given by the AC equivalent of Ohm's law: Z=V/I
Micromotion
The intricate, unique ruffling of each cell.
Time Course Measurement
The total acquisition time is user controlled. Impedance can be sampled as often as several times per second to as slowly as desired. Each impedance reading is plotted as a point, in Ohms or nanofarads (C), verses time.
Resistance
Combining the voltage and phase of the current allows ECIS to break impedance into two parts. Pure resistance is one part, how much of the electrode is covered. Represented in this way: R=V(in phase) / I
Well
A 0.9 cm2 chamber that houses both an electrode and counter electrode where cells can be cultured and observed. Each well holds 500 microliters of medium.
Wounding
When the highest current is applied for several seconds, cell death ensues due to severe electroporation and possible local heating effects.