Patch-clamp technique, description

The flow of ions across the plasma membrane is recorded as current. An extensive description of the patch-clamp technique is given in ref (30). 

To a first approximation, ion channel opening is an all-or-none stochastic event and the effect of a stimulus, chemical or physical, is to alter the probability of channel opening. Patch clamp techniques make it possible to observe the opening or closing of single channels and thus to measure single molecular events. This ability, coupled with recent structural information on the channel, makes possible to a first approximation a molecular description of ion channel function. 

The patch-clamp technique requires very sophisticated equipment (Figure 16.22). Sakmann and Neher (Figure 16.1) received the Nobel Prize in Physiology or Medicine in 1991 for the development of this method. A detailed description of the electrophysiological... 

The measurements of electrochemical impedance, voltammetric (po-larographic) analysis, and spectroelectrochemistry represent a basis for analysis of molecules of biological significance in bulk of solution and at interfaces. These principles are reviewed in the first four chapters. The next three chapters demonstrate how these principles are utilized in voltammetric and interfacial analysis of biomacromolecules such as nucleic acids, proteins, polysaccharides, and viruses in vitro, in the development of biosensors with electrochemical transducers and in in vivo voltammetry. The last two chapters of this volume are devoted to the principles of electrophoresis used for separation analysis of biomolecules and to the theoretical principles and practical description of the patch-clamp technique to an extent suitable for those wishing to initiate research in electrophysiology. 

While an array of analytical techniques has been developed to study various aspects of cells (please see Cell Assays in Microfluidics), this entiy is focused on chemical cytometry. As mentioned above, chemical cytometry refers to methods in which intracellular constituents of a single cell are analyzed by means of a chemical separation. Such methods typically employ capillary electrophoresis for separations, combined with laser-induced fluorescence (LIF) or amperometry for detection. We refer readers to other entries for detailed descriptions of other methods used to evaluate the contents of cells ( Patch Clamp Measurements On-Chip, Mass Spectrometry on a Chip). 

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