Ion-selective Membrane
Ion-selective Membrane - Related Videos
09:18
Measurement of Extracellular Ion Fluxes Using the Ion-selective Self-referencing Microelectrode Technique
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Cited by 6 •
2015
Transporters in cell membranes allow differential segregation of ions across cell membranes or cell layers and play crucial roles during tissue physiology, repair and pathology. We describe the ion-selective self-referencing microelectrode that allows the measurement of specific ion fluxes at single cells and tissues in vivo.
07:38
Functional Characterization of Na+/H+ Exchangers of Intracellular Compartments Using Proton-killing Selection to Express Them at the Plasma Membrane
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Cited by 4 •
2015
The first part of this article shows how to select mutant cell lines expressing vesicular Na+/H+ exchangers at their plasma membrane. The second part provides protocols based on intracellular pH measurements and fast ion uptake, which are used to determine the ion selectivity and the kinetic parameters of these exchangers.
08:06
Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
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2017
The protocol for a novel ion concentration polarization (ICP) platform that can stop the propagation of the ICP zone, regardless of the operating conditions is described. This unique ability of the platform lies in the use of merging ion depletion and enrichment, which are two polarities of the ICP phenomenon.
08:39
Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins
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Cited by 26 •
2017
This article describes how the ion selectivity of channelrhodopsin is determined with electrophysiological whole-cell patch-clamp recordings using HEK293 cells. Here, the experimental procedure for investigating chloride selectivity of an anion-selective channelrhodopsin is demonstrated. However, the procedure is transferable to other channelrhodopsins of distinct selectivity.
03:01
Characterizing Extracellular Space in a Brain Slice Using Ion-Selective and Iontophoresis Microelectrodes
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2025
This video demonstrates how to characterize the extracellular space in a brain slice by using ion-selective and iontophoresis microelectrodes to measure and compare electrical signals. This process helps determine the space's volume fraction and degree of twisting.
FAQs
Selectivity reflects the combined effects of membrane charge, pore size, ion-binding affinity, and the electrochemical gradient. Charge can favor or repel ions, while appropriately sized pores and binding sites influence which species partition into the membrane. The balance among these factors determines both the preferred ion and the extent of competing-ion transport.
The electrochemical gradient provides the driving force for ion transport by combining concentration differences with electrical potential differences. Even when a membrane favors one ion chemically, the gradient influences whether that ion enters, crosses, or accumulates within the membrane. Controlling this gradient therefore helps regulate transport direction and interpret measured ionic responses.
Binding affinity helps an ion partition into the membrane, whereas pore size influences whether the ion can move through available pathways. Strong binding without suitable transport pathways may favor uptake but restrict passage, while large pores without selective interactions may permit competing ions to cross. Their combination helps determine practical selectivity during transport.
In a potentiometric biosensor, selective ion partitioning and transport alter the electrical conditions associated with the membrane. The resulting potential can be related to the presence or behavior of the targeted ionic species. This connects molecular-level recognition with an electrical signal, allowing the membrane to serve as the sensing element in bioengineering measurements.
Design begins by matching membrane interactions to the ion of interest, then considering charge, pore dimensions, binding affinity, and the intended electrochemical gradient. Researchers can evaluate how these features affect partitioning, transport, and electrical response under the conditions relevant to the application. This approach supports controlled sensing, separation, or ionic regulation.
Separation systems exploit differences in how ions interact with and move through the membrane. An ion that partitions more favorably or encounters a more suitable transport pathway can be distinguished from competing species. By controlling membrane properties and the electrochemical environment, researchers can direct ionic transport and improve the selectivity of chemical separations.
Ion-selective membranes can reproduce selected aspects of physiological barriers by controlling which ionic species partition into and cross a material. Researchers can use this controlled transport behavior to examine ionic environments and barrier-like regulation without treating all ions as equivalent. Such models help connect membrane transport principles with biological measurement and device design.
These membranes can convert selective ionic interactions and transport into measurable electrical signals or controlled ionic fluxes. The resulting information may support analyte monitoring, while regulated transport can contribute to devices that manage local ionic conditions. In bioengineering, these capabilities link chemical recognition to diagnostic, therapeutic, and bioelectronic system functions.