Electrophoresis patch-clamp

In the outside-out model, the pipette is attached to the entire cell as in the whole cell model, followed by a sharp pull that causes the cell membrane to break and reseal with the pipette tip (Fig. 3b). With the extracellular region exposed, channel activity as a response to different external stimuli can be probed. This configuration is less common than the inside-out method. Using an outside-out method, single-channel opening activity has been recorded while various neurotransmitters were released. For example, this patch clamp method was used as a detector for capillary electrophoresis separations of GABA, glutamate, and NMDA (7). 

Jardemark K, Orwar O, Jacobson 1, Moscho A, Zare RN. 27. Patch clamp detection in capillary electrophoresis. Anal. Chem. 1997 69 3427-3434. 

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). 

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. 

Previous studies have examined the release of chemical messengers on the whole-cell level through capillary electrophoresis and microcolumn liquid chromatography with electrochanical detection [6]. Although these techniques provide both qualitative and quantitative information about the average vesicular chemical content, they lack the temporal and spatial resolution needed for the precise detection of individual release events [6], Methods to observe and quantitate individual events have traditionally revolved around electron microscopy and patch-clamp capacitance measurements [7],... 

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