Electrochemical response of biological membranes to localized currents and external electric fields

Fuente: arXiv
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Autori principali: Fernandes, Joshua B., Row, Hyeongjoo, Mandadapu, Kranthi K., Shekhar, Karthik
Natura: Preprint
Pubblicazione: 2025
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author Fernandes, Joshua B.
Row, Hyeongjoo
Mandadapu, Kranthi K.
Shekhar, Karthik
author_facet Fernandes, Joshua B.
Row, Hyeongjoo
Mandadapu, Kranthi K.
Shekhar, Karthik
contents Electrochemical phenomena in biology often unfold in confined geometries where micrometer- to millimeter-scale domains coexist with nanometer-scale interfacial diffuse charge layers. We analyze a model lipid membrane-electrolyte system where an ion channel-like current flows across the membrane while parallel electrodes simultaneously apply a step voltage, emulating an extrinsic electric field. Matched asymptotic expansions of the Poisson-Nernst-Planck equations show that, under physiological conditions, the diffuse charge layers rapidly reach a quasi-steady state, and the bulk electrolyte remains electroneutral. As a result, all free charge is confined to the nanometer-scale screening layers at the membrane and electrode interfaces. The bulk electric potential satisfies Laplace's equation, and is dynamically coupled to the interfacial layers through time-dependent boundary conditions. This multiscale coupling partitions the space-time response into distinct regimes. At sufficiently long times, we show that the system can be represented by an equivalent circuit analogous to those used in classical cable theory. We derive closed-form expressions of the transmembrane potential within each regime, and verify them against nonlinear numerical simulations. Our results show how electrode-induced screening and confinement effects influence the electrochemical response over multiple length and time scales in biological systems.
format Preprint
id arxiv_https___arxiv_org_abs_2508_14001
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Electrochemical response of biological membranes to localized currents and external electric fields
Fernandes, Joshua B.
Row, Hyeongjoo
Mandadapu, Kranthi K.
Shekhar, Karthik
Soft Condensed Matter
Biological Physics
Subcellular Processes
Electrochemical phenomena in biology often unfold in confined geometries where micrometer- to millimeter-scale domains coexist with nanometer-scale interfacial diffuse charge layers. We analyze a model lipid membrane-electrolyte system where an ion channel-like current flows across the membrane while parallel electrodes simultaneously apply a step voltage, emulating an extrinsic electric field. Matched asymptotic expansions of the Poisson-Nernst-Planck equations show that, under physiological conditions, the diffuse charge layers rapidly reach a quasi-steady state, and the bulk electrolyte remains electroneutral. As a result, all free charge is confined to the nanometer-scale screening layers at the membrane and electrode interfaces. The bulk electric potential satisfies Laplace's equation, and is dynamically coupled to the interfacial layers through time-dependent boundary conditions. This multiscale coupling partitions the space-time response into distinct regimes. At sufficiently long times, we show that the system can be represented by an equivalent circuit analogous to those used in classical cable theory. We derive closed-form expressions of the transmembrane potential within each regime, and verify them against nonlinear numerical simulations. Our results show how electrode-induced screening and confinement effects influence the electrochemical response over multiple length and time scales in biological systems.
title Electrochemical response of biological membranes to localized currents and external electric fields
topic Soft Condensed Matter
Biological Physics
Subcellular Processes
url https://arxiv.org/abs/2508.14001