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Ion permeability of artificial membranes evaluated by diffusion potential and electrical resistance measurements (719.1)
Author(s) -
Shlyonsky Vadim
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.719.1
Subject(s) - membrane , ionic bonding , diffusion , valinomycin , chemistry , membrane potential , permeability (electromagnetism) , analytical chemistry (journal) , ion , chemical engineering , chromatography , thermodynamics , organic chemistry , biochemistry , physics , engineering
A novel model of artificial membranes that provides efficient assistance in teaching the origins of diffusion potentials is proposed. These membranes are made of polycarbonate filters fixed to 12 mm plastic rings and then saturated with a mixture of creosol and n‐decane. Electrical resistance and potential difference across these membranes can be easily measured using low‐cost volt‐ohmmeter and home‐made Ag/AgCl electrodes. The advantage of the model is the lack of ionic selectivity of the membrane, which can be modified by introduction of different ionophores to the organic liquid mixture. Membrane treated with the mixture containing valinomycin generates voltages from ‐53 mV to ‐25 mV in the presence of a 10‐fold KCl gradient (in‐to‐out) and from ‐79 mV to ‐53 mV in the presence of a bi‐ionic KCl/NaCl gradient (in‐to‐out). This latter bi‐ionic gradient potential reverses to a value from +9 mV to +20 mV when monensin is present in the organic liquid mixture. Thus, the model can be build stepwise, i.e. all factors leading to the development of diffusion potentials can be introduced sequentially, helping to understand the quantitative relationships of ionic gradients and differential membrane permeability in the generation of cell electrical signals. Grant Funding Source : Supported by FER (ULB)