Membranes 2014, 4(2), 257-274; doi:10.3390/membranes4020257

Membrane Potential Generated by Ion Adsorption

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Received: 3 April 2014; in revised form: 3 June 2014 / Accepted: 4 June 2014 / Published: 12 June 2014
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Abstract: It has been widely acknowledged that the Goldman-Hodgkin-Katz (GHK) equation fully explains membrane potential behavior. The fundamental facet of the GHK equation lies in its consideration of permeability of membrane to ions, when the membrane serves as a separator for separating two electrolytic solutions. The GHK equation describes that: variation of membrane permeability to ion in accordance with ion species results in the variation of the membrane potential. However, nonzero potential was observed even across the impermeable membrane (or separator) separating two electrolytic solutions. It gave rise to a question concerning the validity of the GHK equation for explaining the membrane potential generation. In this work, an alternative theory was proposed. It is the adsorption theory. The adsorption theory attributes the membrane potential generation to the ion adsorption onto the membrane (or separator) surface not to the ion passage through the membrane (or separator). The computationally obtained potential behavior based on the adsorption theory was in good agreement with the experimentally observed potential whether the membrane (or separator) was permeable to ions or not. It was strongly speculated that the membrane potential origin could lie primarily in the ion adsorption on the membrane (or separator) rather than the membrane permeability to ions. It might be necessary to reconsider the origin of membrane potential which has been so far believed explicable by the GHK equation.
Keywords: membrane potential; Goldman-Hodgkin-Katz equation; ion permeability; ion adsorption; Langmuir isotherm; Boltzmann distribution; Poisson-Boltzmann equation
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MDPI and ACS Style

Tamagawa, H.; Morita, S. Membrane Potential Generated by Ion Adsorption. Membranes 2014, 4, 257-274.

AMA Style

Tamagawa H, Morita S. Membrane Potential Generated by Ion Adsorption. Membranes. 2014; 4(2):257-274.

Chicago/Turabian Style

Tamagawa, Hirohisa; Morita, Sachi. 2014. "Membrane Potential Generated by Ion Adsorption." Membranes 4, no. 2: 257-274.

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