Membrane Potential Generated by Ion Adsorption
Department of Human and Information Systems, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
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Membranes 2014, 4(2), 257-274; https://doi.org/10.3390/membranes4020257
Received: 3 April 2014 / Revised: 3 June 2014 / Accepted: 4 June 2014 / Published: 12 June 2014
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.
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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. https://doi.org/10.3390/membranes4020257
AMA Style
Tamagawa H, Morita S. Membrane Potential Generated by Ion Adsorption. Membranes. 2014; 4(2):257-274. https://doi.org/10.3390/membranes4020257
Chicago/Turabian StyleTamagawa, Hirohisa; Morita, Sachi. 2014. "Membrane Potential Generated by Ion Adsorption" Membranes 4, no. 2: 257-274. https://doi.org/10.3390/membranes4020257
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