Measurement of Membrane Capacitance in Epithelial Monolayers

Biological membranes serve as physical barriers and electrical insulators to separate different aqueous compartments, such as the intracellular and extracellular environments. In electrical terms, membranes that separate highly conductive aqueous media represent capacitors. What makes this definition particularly useful to biologists is that the capacitance of a capacitor is proportional to its area. By measuring membrane capacitance, one can get an estimate of the actual area of a cell membrane. The proportionality constant sufficient for most biological membranes is 1 μF/cm² (1 ).