Biomembranes electrical potentials

Fromherz, P. Lipid coumarin dye as a probe of interfacial electrical potential in biomembranes. Methods Enzymol. 1989,171,376-387. 

When two electrolyte solutions at different concentrations are separated by an ion--permeable membrane, a potential difference is generally established between the two solutions. This potential difference, known as membrane potential, plays an important role in electrochemical phenomena observed in various biomembrane systems. In the stationary state, the membrane potential arises from both the diffusion potential [1,2] and the membrane boundary potential [3-6]. To calculate the membrane potential, one must simultaneously solve the Nernst-Planck equation and the Poisson equation. Analytic formulas for the membrane potential can be derived only if the electric held within the membrane is assumed to be constant [1,2]. In this chapter, we remove this constant held assumption and numerically solve the above-mentioned nonlinear equations to calculate the membrane potential [7]. 

It has been recognized that macromolecules and macromolecular organizations such as biological membranes are particularly effective media for the coupling of high electric fields with biochemical reactivity. Indeed, all biomembranes appear to be associated with electric membrane potentials. 

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