Electrical characterisation and dynamics of transport

Ion channels lie at the interface between two areas of science: as physiological relays in biology and as picoampere/millivolt conductors in physics. It is precisely the complementarity of these two worlds which led to the emergence of the novel patch-clamp technique. By providing direct access to the activity of the protein channel, the patch clamp brought about a revolution in the molecular scale study of biomembranes. This section discusses the experimental aspects of this electrophysiological technique, after a brief summary of the basic physical concepts, and illustrates the way ion channels are involved at the very heart of the main cell functions. Finally, we outline their privileged position as molecular targets of therapeutic importance in the treatment of channelopathies (ion channel disorders). While the patch clamp is considered as the 'standard' for studying the electrical activity of cells, one should not forget the current technological developments that have sprung from it, combining performance and high analysis rates in the discovery of new molecules. Throughout this section, the reader will be pointed toward the literature concerning channel biology, the patch-clamp method, and the emergence of parallel electrophysiological techniques.