Abstract: A method of detecting exocytosis of a target molecule from a population of cells derived from a human subject, includes applying first and second electrical signals, each having a respective frequency, across the population of cells. Each of the first and second electrical signals being either an alternating current or an alternating voltage. The method includes measuring a first voltage change if the first electrical signal is an alternating current or measuring a first current change if the first electrical signal is an alternating voltage, and measuring a second voltage change if the second electrical signal is an alternating current or measuring a second current change if the second electrical signal is an alternating voltage. The method includes determining an electrical impedance of the population of cells, a change in that impedance indicating an amount of the target molecule released from the population of cells.

Abstract: Embodiments of various aspects described herein relate to methods and systems for detecting exocytosis or endocytosis of a target molecule from or into a population of cells, in part based on impedance analysis of the population of cells after they are exposed to an alternating current applied at two or more frequencies or to a repetitive voltage waveform. In some embodiments, the methods and systems described herein can be used for assessing viability and/or potency of the population of cells, and/or identifying a secretagogue for the target molecule released from the population of cells.

Abstract: An electronic circuit interruption device having a plurality of protection, indication and control options includes a dedicated printed circuit board having electrical connection with operating circuits controlling each of the several options. Electrical connections between the operating circuits and the circuit interruption controller is made through corresponding dedicated resistors. Option selection is obtained by removal of resistors connecting with non-selected circuits on the printed circuit board.