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Advances in Artificial and Biological Membranes, Volume II
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Advances in Artificial and Biological Membranes, Volume II

A special issue of Membranes (ISSN 2077-0375). This special issue belongs to the section "Membrane Applications".

Deadline for manuscript submissions: closed (30 November 2023) | Viewed by 11004

Special Issue Editors

Prof. Dr. Andrzej Lewenstam

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Guest Editor
1. Faculty of Materials Science and Ceramics, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland
2. Johan Gadolin Process Chemistry Centre, c/o Centre for Process Analytical Chemistry and Sensor Technology (ProSens), Åbo Akademi University, Biskopsgatan 8, 20500 Åbo-Turku, Finland
Interests: sensor technology; electroanalysis; analytical/clinical chemistry; ion-selective electrodes; ion-sensor architectures; membranes and electroactive materials for ion-sensors
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Ritu Kataky

E-Mail Website
Guest Editor
Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, UK
Interests: electrochemistry; electrochemical sensors in real media; liquid-liquid interface; biosensors; biofilms
Prof. Dr. Krzysztof Dołowy

E-Mail Website
Guest Editor
Department of Biophysics, Warsaw University of Life Sciences – SGGW, 159 Nowoursynowska St., 02-776 Warsaw, Poland
Interests: biological membranes; ion channels and transporters; epithelial transport of ions and water; mitochondria bioelectrochemistry; sensors; microfluidic systems; mathematical modeling
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Li Niu

E-Mail Website
Guest Editor
1. School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China
2. School of Chemical Engineering and Technology, Sun Yat-sen University, Guangzhou 510276, China
Interests: electrochemical sensors and materials; wearable devices
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues

Ion sensors, conventionally known as ion-selective membrane electrodes, were founded a hundred years ago through the invention of a pH electrode with a glass membrane (in 1906, Cremer, and in 1909, Haber and Klemensiewicz). This electrode type having a symmetric design with an internal contact created by a solution, paved the way to the present architectures of a large family of chemical sensors and biosensors.

Today, there are numerous sensors with acting membranes composed of glass, solid-state, plastics, and composites, as well many internal contacts composed of conducting polymers, carbon nanotubes, graphene, conducting clays, and composites. For this reason, the sensors can be miniaturized, created service-free, and produced by a mass fabrication technique such as 3D printing. Responses are now treated by models able to access time-and-space domains of the sensors. Supported by advanced modeling, ion sensors and biosensors are now deliberately calibration-free, may undergo automatic quality checks, and can act in ad hoc and routine applications such as theaters, hospitals, sports, water control, etc.

The heart of the sensor is always the same: an artificial or biological membrane or film able to develop a response to analyte due to selective, fast, and reversible processes at the sample–membrane interface or membrane/film bulk.

The aim of this Special Issue is to present retrospective outlooks as well as novel waves and the progress that has been recently realized in sensor technology, all aspects contributing to the successful advancement of the design, understanding, and application of ion sensors and biosensors being of interest, the submission site ready to receive your sensor science contributions.

Prof. Dr. Andrzej Lewenstam
Prof. Dr. Ritu Kataky
Prof. Dr. Krzysztof Dołowy
Prof. Dr. Li Niu
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Membranes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • ion-sensor architectures
  • membranes and electroactive materials for ion-sensors
  • new fabrication schemes
  • response interpretation and modeling
  • new applications: wearable, disposable, remotely controlled ion-sensors
  • routine ion-sensors application

Related Special Issue

Published Papers (15 papers)

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Editorial

Jump to: Research, Review

5 pages, 201 KiB  
Editorial
Special Issue “Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs, and Applications for Ion Measurement”
by Andrzej Lewenstam and Krzysztof Dołowy
Membranes 2020, 10(12), 427; https://doi.org/10.3390/membranes10120427 - 15 Dec 2020
Cited by 3 | Viewed by 1640
Abstract
Ion sensors, conventionally known as ion-selective membrane electrodes, were devised 100 years ago with the invention of a pH electrode with a glass membrane (in 1906 Cremer, in 1909 Haber and Klemensiewicz) [...] Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)

Research

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14 pages, 5523 KiB  
Article
Understanding Bidirectional Water Transport across Bronchial Epithelial Cell Monolayers: A Microfluidic Approach
by Miroslaw Zajac, Slawomir Jakiela and Krzysztof Dolowy
Membranes 2023, 13(12), 901; https://doi.org/10.3390/membranes13120901 - 06 Dec 2023
Viewed by 1474
Abstract
Deciphering the dynamics of water transport across bronchial epithelial cell monolayers is pivotal for unraveling respiratory physiology and pathology. In this study, we employ an advanced microfluidic system to explore bidirectional water transport across 16HBE14σ bronchial epithelial cells. Previous experiments unveiled electroneutral multiple [...] Read more.
Deciphering the dynamics of water transport across bronchial epithelial cell monolayers is pivotal for unraveling respiratory physiology and pathology. In this study, we employ an advanced microfluidic system to explore bidirectional water transport across 16HBE14σ bronchial epithelial cells. Previous experiments unveiled electroneutral multiple ion transport, with chloride ions utilizing transcellular pathways and sodium ions navigating both paracellular and transcellular routes. Unexpectedly, under isoosmotic conditions, rapid bidirectional movement of Na+ and Cl− was observed, leading to the hypothesis of a substantial transport of isoosmotic solution (145 mM NaCl) across cell monolayers. To validate this conjecture, we introduce an innovative microfluidic device, offering a 500-fold sensitivity improvement in quantifying fluid flow. This system enables the direct measurement of minuscule fluid volumes traversing cell monolayers with unprecedented precision. Our results challenge conventional models, indicating a self-regulating mechanism governing water transport that involves the CFTR channel and anion exchangers. In healthy subjects, equilibrium is achieved at an apical potential of Δφap = −30 mV, while subjects with cystic fibrosis exhibit modulation by an anion exchanger, reaching equilibrium at [Cl] = 67 mM in the airway surface liquid. This nuanced electrochemical basis for bidirectional water transport in bronchial epithelia sheds light on physiological intricacies and introduces a novel perspective for understanding respiratory conditions. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes, Volume II)
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11 pages, 2904 KiB  
Article
Changes in Ion Transport across Biological Membranes Exposed to Particulate Matter
by Jakub Hoser, Adrianna Dabrowska, Miroslaw Zajac and Piotr Bednarczyk
Membranes 2023, 13(9), 763; https://doi.org/10.3390/membranes13090763 - 29 Aug 2023
Viewed by 759
Abstract
The cells of living organisms are surrounded by the biological membranes that form a barrier between the internal and external environment of the cells. Cell membranes serve as barriers and gatekeepers. They protect cells against the entry of undesirable substances and are the [...] Read more.
The cells of living organisms are surrounded by the biological membranes that form a barrier between the internal and external environment of the cells. Cell membranes serve as barriers and gatekeepers. They protect cells against the entry of undesirable substances and are the first line of interaction with foreign particles. Therefore, it is very important to understand how substances such as particulate matter (PM) interact with cell membranes. To investigate the effect of PM on the electrical properties of biological membranes, a series of experiments using a black lipid membrane (BLM) technique were performed. L-α-Phosphatidylcholine from soybean (azolectin) was used to create lipid bilayers. PM samples of different diameters (<4 (SRM-PM4.0) and <10 μm (SRM-PM10) were purchased from The National Institute of Standards and Technology (USA) to ensure the repeatability of the measurements. Lipid membranes with incorporated gramicidin A (5 pg/mL) ion channels were used to investigate the effect of PM on ion transport. The ionic current passing through the azolectin membranes was measured in ionic gradients (50/150 mM KCl on cis/trans side). In parallel, the electric membrane capacitance measurements, analysis of the conductance and reversal potential were performed. Our results have shown that PM at concentration range from 10 to 150 μg/mL reduced the basal ionic current at negative potentials while increased it at positive ones, indicating the interaction between lipids forming the membrane and PM. Additionally, PM decreased the gramicidin A channel activity. At the same time, the amplitude of channel openings as well as single channel conductance and reversal potential remained unchanged. Lastly, particulate matter at a concentration of 150 μg/mL did not affect the electric membrane capacity to any significant extent. Understanding the interaction between PM and biological membranes could aid in the search for effective cytoprotective strategies. Perhaps, by the use of an artificial system, we will learn to support the consequences of PM-induced damage. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes, Volume II)
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19 pages, 10882 KiB  
Article
An Electrochemistry and Computational Study at an Electrified Liquid–Liquid Interface for Studying Beta-Amyloid Aggregation
by Bongiwe Silwane, Mark Wilson and Ritu Kataky
Membranes 2023, 13(6), 584; https://doi.org/10.3390/membranes13060584 - 05 Jun 2023
Viewed by 1102
Abstract
Amphiphilic peptides, such as Aß amyloids, can adsorb at an interface between two immiscible electrolyte solutions (ITIES). Based on previous work (vide infra), a hydrophilic/hydrophobic interface is used as a simple biomimetic system for studying drug interactions. The ITIES provides a 2D interface [...] Read more.
Amphiphilic peptides, such as Aß amyloids, can adsorb at an interface between two immiscible electrolyte solutions (ITIES). Based on previous work (vide infra), a hydrophilic/hydrophobic interface is used as a simple biomimetic system for studying drug interactions. The ITIES provides a 2D interface to study ion-transfer processes associated with aggregation, as a function of Galvani potential difference. Here, the aggregation/complexation behaviour of Aβ(1-42) is studied in the presence of Cu (II) ions, together with the effect of a multifunctional peptidomimetic inhibitor (P6). Cyclic and differential pulse voltammetry proved to be particularly sensitive to the detection of the complexation and aggregation of Aβ(1-42), enabling estimations of changes in lipophilicity upon binding to Cu (II) and P6. At a 1:1 ratio of Cu (II):Aβ(1-42), fresh samples showed a single DPV (Differential Pulse Voltammetry) peak half wave transfer potential (E1/2) at 0.40 V. Upon increasing the ratio of Cu (II) two-fold, fluctuations were observed in the DPVs, indicating aggregation. The approximate stoichiometry and binding properties of Aβ(1-42) during complexation with Cu (II) were determined by performing a differential pulse voltammetry (DPV) standard addition method, which showed two binding regimes. A pKa of 8.1 was estimated, with a Cu:Aβ1-42 ratio~1:1.7. Studies using molecular dynamics simulations of peptides at the ITIES show that Aβ(1-42) strands interact through the formation of β-sheet stabilised structures. In the absence of copper, binding/unbinding is dynamic, and interactions are relatively weak, leading to the observation of parallel and anti-parallel arrangements of β-sheet stabilised aggregates. In the presence of copper ions, strong binding occurs between a copper ion and histidine residues on two peptides. This provides a convenient geometry for inducing favourable interactions between folded β-sheet structures. Circular Dichroism spectroscopy (CD spectroscopy) was used to support the aggregation behaviour of the Aβ(1-42) peptides following the addition of Cu (II) and P6 to the aqueous phase. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes, Volume II)
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12 pages, 1594 KiB  
Article
Directly Using Ti3C2Tx MXene for a Solid-Contact Potentiometric pH Sensor toward Wearable Sweat pH Monitoring
by Rongfeng Liang, Lijie Zhong, Yirong Zhang, Yitian Tang, Meixue Lai, Tingting Han, Wei Wang, Yu Bao, Yingming Ma, Shiyu Gan and Li Niu
Membranes 2023, 13(4), 376; https://doi.org/10.3390/membranes13040376 - 25 Mar 2023
Cited by 2 | Viewed by 1687
Abstract
The level of hydrogen ions in sweat is one of the most important physiological indexes for the health state of the human body. As a type of two-dimensional (2D) material, MXene has the advantages of superior electrical conductivity, a large surface area, and [...] Read more.
The level of hydrogen ions in sweat is one of the most important physiological indexes for the health state of the human body. As a type of two-dimensional (2D) material, MXene has the advantages of superior electrical conductivity, a large surface area, and rich functional groups on the surface. Herein, we report a type of Ti3C2Tx-based potentiometric pH sensor for wearable sweat pH analysis. The Ti3C2Tx was prepared by two etching methods, including a mild LiF/HCl mixture and HF solution, which was directly used as the pH-sensitive materials. Both etched Ti3C2Tx showed a typical lamellar structure and exhibited enhanced potentiometric pH responses compared with a pristine precursor of Ti3AlC2. The HF-Ti3C2Tx disclosed the sensitivities of −43.51 ± 0.53 mV pH–1 (pH 1–11) and −42.73 ± 0.61 mV pH–1 (pH 11–1). A series of electrochemical tests demonstrated that HF-Ti3C2Tx exhibited better analytical performances, including sensitivity, selectivity, and reversibility, owing to deep etching. The HF-Ti3C2Tx was thus further fabricated as a flexible potentiometric pH sensor by virtue of its 2D characteristic. Upon integrating with a solid-contact Ag/AgCl reference electrode, the flexible sensor realized real-time monitoring of pH level in human sweat. The result disclosed a relatively stable pH value of ~6.5 after perspiration, which was consistent with the ex situ sweat pH test. This work offers a type of MXene-based potentiometric pH sensor for wearable sweat pH monitoring. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes, Volume II)
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11 pages, 1666 KiB  
Article
Interactions of Surfactants with Biomimetic Membranes—2. Generation of Electric Potential with Non-Ionic Surfactants
by Nikolai M. Kocherginsky and Brajendra K. Sharma
Membranes 2023, 13(3), 353; https://doi.org/10.3390/membranes13030353 - 18 Mar 2023
Cited by 1 | Viewed by 1311
Abstract
It is discovered that noncharged surfactants lead to electric effects that interact with biomimetic membranes made of nitrocellulose filters, which are impregnated with fatty acid esters. At a surfactant concentration as low as 64 microM in one of the solutions, they lead to [...] Read more.
It is discovered that noncharged surfactants lead to electric effects that interact with biomimetic membranes made of nitrocellulose filters, which are impregnated with fatty acid esters. At a surfactant concentration as low as 64 microM in one of the solutions, they lead to the transient formation of transmembrane electric potential. Maximum changes of this potential are proportional to the log of noncharged surfactant concentrations when it changes by three orders of magnitude. We explain this new and nontrivial effect in terms of an earlier suggested physicochemical mechanics approach and noncharged surfactants transient changes induced by membrane permeability for inorganic ions. It could be used to imitate the interactions of non-ionic drugs with biological membranes. The effect may also be used in determining the concentration of these surfactants and other non-ionic chemicals of concern, such as pharmaceuticals and personal care products. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes, Volume II)
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15 pages, 2205 KiB  
Article
Novel Experimental Setup for Coulometric Signal Transduction of Ion-Selective Electrodes
by Naela Delmo, Zekra Mousavi, Tomasz Sokalski and Johan Bobacka
Membranes 2022, 12(12), 1221; https://doi.org/10.3390/membranes12121221 - 02 Dec 2022
Cited by 4 | Viewed by 1694
Abstract
In this work, a novel and versatile experimental setup for coulometric signal transduction of ion-selective electrodes (ISEs) is introduced and studied. It is based on a constant potential coulometric measurement carried out using a one-compartment three-electrode electrochemical cell. In the setup, a potassium [...] Read more.
In this work, a novel and versatile experimental setup for coulometric signal transduction of ion-selective electrodes (ISEs) is introduced and studied. It is based on a constant potential coulometric measurement carried out using a one-compartment three-electrode electrochemical cell. In the setup, a potassium ion-selective electrode (K+- ISE) is connected as the reference electrode (RE). A poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS)-based electrode with a dummy membrane (DM) and a glassy carbon (GC) rod are connected as the working electrode (WE) and counter electrode (CE), respectively. Adding a non-selective dummy membrane to the structure of the WE facilitates the regulation of the measured signal and response time. The results from electrochemical impedance spectroscopy measurements carried out on the WE showed that the time constant is profoundly influenced by the dummy membrane thickness. In addition, the redox capacitance of the PEDOT:PSS film shows a better correlation with the electrode area than the film thickness. Sequential addition/dilution experiments showed the improvement of current and cumulated charge signals in the new setup studied in this work compared to the setup used in the original coulometric signal transduction method. Both conventional ISEs and solid-contact ISEs (SCISEs) were used in this work. The results showed that the coulometric response was independent of the type of ISE used as RE, confirming the versatility of the novel set-up. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes, Volume II)
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15 pages, 2530 KiB  
Article
Electrically Enhanced Sensitivity (EES) of Ion-Selective Membrane Electrodes and Membrane-Based Ion Sensors
by Jan Migdalski and Andrzej Lewenstam
Membranes 2022, 12(8), 763; https://doi.org/10.3390/membranes12080763 - 03 Aug 2022
Cited by 1 | Viewed by 1726
Abstract
The use of external electronic enforcement in ion-sensor measurements is described. The objective is to improve the open-circuit (potentiometric) sensitivity of ion sensors. The sensitivity determines the precision of analyte determination and has been of interest since the beginning of ion-sensor technology. Owing [...] Read more.
The use of external electronic enforcement in ion-sensor measurements is described. The objective is to improve the open-circuit (potentiometric) sensitivity of ion sensors. The sensitivity determines the precision of analyte determination and has been of interest since the beginning of ion-sensor technology. Owing to the theoretical interpretation founded by W.E. Nernst, the sensitivity is characterized by the slope and numerically predicted. It is empirically determined and validated during calibration by measuring an electromotive force between the ion sensor and the reference electrode. In practice, this measurement is made with commercial potentiometers that function as unaltered “black boxes”. This report demonstrates that by gaining access to a meter’s electrical systems and allowing for versatile signal summations, the empirical slope can be increased favorably. To prove the validity of the approach presented, flow-through ion-sensor blocks used in routine measurements of blood electrolytes (Na+, K+, Li+, Cl−) and multielectrode probes with flat surfaces, similar to those applied previously for monitoring transmembrane fluxes of Na+, K+, Cl− through living biological cells, are used. Several options to serve real-life electroanalytical challenges, including linear calibration for sensors with high-resistance membranes, responses with non-Nernstian slopes, non-linear calibration, and discrimination of nonfunctional sensors, are shown. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes, Volume II)
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17 pages, 7686 KiB  
Article
Plasticized PVC Membrane Modified Electrodes: Voltammetry of Highly Hydrophobic Compounds
by Ernő Lindner, Marcin Guzinski, Bradford Pendley and Edward Chaum
Membranes 2020, 10(9), 202; https://doi.org/10.3390/membranes10090202 - 27 Aug 2020
Cited by 10 | Viewed by 4326
Abstract
In the last 50 years, plasticized polyvinyl chloride (PVC) membranes have gained unique importance in chemical sensor development. Originally, these membranes separated two solutions in conventional ion-selective electrodes. Later, the same membranes were applied over a variety of supporting electrodes and used in [...] Read more.
In the last 50 years, plasticized polyvinyl chloride (PVC) membranes have gained unique importance in chemical sensor development. Originally, these membranes separated two solutions in conventional ion-selective electrodes. Later, the same membranes were applied over a variety of supporting electrodes and used in both potentiometric and voltammetric measurements of ions and electrically charged molecules. The focus of this paper is to demonstrate the utility of the plasticized PVC membrane modified working electrode for the voltammetric measurement of highly lipophilic molecules. The plasticized PVC membrane prevents electrode fouling, extends the detection limit of the voltammetric methods to sub-micromolar concentrations, and minimizes interference by electrochemically active hydrophilic analytes. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)
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18 pages, 3374 KiB  
Article
Optimization of Ruthenium Dioxide Solid Contact in Ion-Selective Electrodes
by Nikola Lenar, Beata Paczosa-Bator and Robert Piech
Membranes 2020, 10(8), 182; https://doi.org/10.3390/membranes10080182 - 09 Aug 2020
Cited by 19 | Viewed by 2579
Abstract
Ruthenium dioxide occurs in two morphologically varied structures: anhydrous and hydrous form; both of them were studied in the scope of this work and applied as mediation layers in ion-selective electrodes. The differences between the electrochemical properties of those two materials underlie their [...] Read more.
Ruthenium dioxide occurs in two morphologically varied structures: anhydrous and hydrous form; both of them were studied in the scope of this work and applied as mediation layers in ion-selective electrodes. The differences between the electrochemical properties of those two materials underlie their diverse structure and hydration properties, which was demonstrated in the paper. One of the main differences is the occurrence of structural water in RuO2•xH2O, which creates a large inner surface available for ion transport and was shown to be a favorable feature in the context of designing potentiometric sensors. Both materials were examined with SEM microscope, X-ray diffractometer, and contact angle microscope, and the results revealed that the hydrous form can be characterized as a porous structure with a smaller crystallite size and more hydrophobic properties contrary to the anhydrous form. Potentiometric and electrochemical tests carried out on designed GCD/RuO2/K+-ISM and GCD/RuO2•xH2O/K+-ISM electrodes proved that the loose porous microstructure with chemically bounded water, which is characteristic for the hydrous form, ensures the high electrical capacitance of electrodes (up to 1.2 mF) with consequently more stable potential (with the potential drift of 0.0015 mV/h) and a faster response (of a few seconds). Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)
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29 pages, 2738 KiB  
Article
Precipitation of Inorganic Salts in Mitochondrial Matrix
by Jerzy J. Jasielec, Robert Filipek, Krzysztof Dołowy and Andrzej Lewenstam
Membranes 2020, 10(5), 81; https://doi.org/10.3390/membranes10050081 - 27 Apr 2020
Cited by 9 | Viewed by 6101
Abstract
In the mitochondrial matrix, there are insoluble, osmotically inactive complexes that maintain a constant pH and calcium concentration. In the present paper, we examine the properties of insoluble calcium and magnesium salts, such as phosphates, carbonates and polyphosphates, which might play this role. [...] Read more.
In the mitochondrial matrix, there are insoluble, osmotically inactive complexes that maintain a constant pH and calcium concentration. In the present paper, we examine the properties of insoluble calcium and magnesium salts, such as phosphates, carbonates and polyphosphates, which might play this role. We find that non-stoichiometric, magnesium-rich carbonated apatite, with very low crystallinity, precipitates in the matrix under physiological conditions. Precipitated salt acts as pH buffer, and, hence, can contribute in maintaining ATP production in ischemic conditions, which delays irreversible damage to heart and brain cells after stroke. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)
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13 pages, 6597 KiB  
Article
Measurement of Multi Ion Transport through Human Bronchial Epithelial Cell Line Provides an Insight into the Mechanism of Defective Water Transport in Cystic Fibrosis
by Miroslaw Zajac, Andrzej Lewenstam, Piotr Bednarczyk and Krzysztof Dolowy
Membranes 2020, 10(3), 43; https://doi.org/10.3390/membranes10030043 - 12 Mar 2020
Cited by 8 | Viewed by 3963
Abstract
We measured concentration changes of sodium, potassium, chloride ions, pH and the transepithelial potential difference by means of ion-selective electrodes, which were placed on both sides of a human bronchial epithelial 16HBE14σ cell line grown on a porous support in the presence of [...] Read more.
We measured concentration changes of sodium, potassium, chloride ions, pH and the transepithelial potential difference by means of ion-selective electrodes, which were placed on both sides of a human bronchial epithelial 16HBE14σ cell line grown on a porous support in the presence of ion channel blockers. We found that, in the isosmotic transepithelial concentration gradient of either sodium or chloride ions, there is an electroneutral transport of the isosmotic solution of sodium chloride in both directions across the cell monolayer. The transepithelial potential difference is below 3 mV. Potassium and pH change plays a minor role in ion transport. Based on our measurements, we hypothesize that in a healthy bronchial epithelium, there is a dynamic balance between water absorption and secretion. Water absorption is caused by the action of two exchangers, Na/H and Cl/HCO3, secreting weakly dissociated carbonic acid in exchange for well dissociated NaCl and water. The water secretion phase is triggered by an apical low volume-dependent factor opening the Cystic Fibrosis Transmembrane Regulator CFTR channel and secreting anions that are accompanied by paracellular sodium and water transport. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)
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22 pages, 2616 KiB  
Article
Reference Electrodes with Polymer-Based Membranes—Comprehensive Performance Characteristics
by Peter Lingenfelter, Bartosz Bartoszewicz, Jan Migdalski, Tomasz Sokalski, Mirosław M. Bućko, Robert Filipek and Andrzej Lewenstam
Membranes 2019, 9(12), 161; https://doi.org/10.3390/membranes9120161 - 29 Nov 2019
Cited by 19 | Viewed by 5904
Abstract
Several types of liquid membrane and solid-state reference electrodes based on different plastics were fabricated. In the membranes studied, equitransferent organic (QB) and inorganic salts (KCl) are dispersed in polyvinyl chloride (PVC), polyurethane (PU), urea-formaldehyde resin (UF), polyvinyl acetate (PVA), as well as [...] Read more.
Several types of liquid membrane and solid-state reference electrodes based on different plastics were fabricated. In the membranes studied, equitransferent organic (QB) and inorganic salts (KCl) are dispersed in polyvinyl chloride (PVC), polyurethane (PU), urea-formaldehyde resin (UF), polyvinyl acetate (PVA), as well as remelted KCl in order to show the matrix impact on the reference membranes’ behavior. The comparison of potentiometic performance was made using specially designed standardized testing protocols. A problem in the reference electrode research and literature has been a lack of standardized testing, which leads to difficulties in comparing different types, qualities, and properties of reference electrodes. Herein, several protocols were developed to test the electrodes’ performance with respect to stability over time, pH sensitivity, ionic strength, and various ionic species. All of the prepared reference electrodes performed well in at least some respect and would be suitable for certain applications as described in the text. Most of the reference types, however, demonstrated some weakness that had not been previously highlighted in the literature, due in large part to the lack of exhaustive and/or consistent testing protocols. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)
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Review

Jump to: Editorial, Research

14 pages, 593 KiB  
Review
Unintended Changes of Ion-Selective Membranes Composition—Origin and Effect on Analytical Performance
by Krzysztof Maksymiuk, Emilia Stelmach and Agata Michalska
Membranes 2020, 10(10), 266; https://doi.org/10.3390/membranes10100266 - 28 Sep 2020
Cited by 22 | Viewed by 3391
Abstract
Ion-selective membranes, as used in potentiometric sensors, are mixtures of a few important constituents in a carefully balanced proportion. The changes of composition of the ion-selective membrane, both qualitative and quantitative, affect the analytical performance of sensors. Different constructions and materials applied to [...] Read more.
Ion-selective membranes, as used in potentiometric sensors, are mixtures of a few important constituents in a carefully balanced proportion. The changes of composition of the ion-selective membrane, both qualitative and quantitative, affect the analytical performance of sensors. Different constructions and materials applied to improve sensors result in specific conditions of membrane formation, in consequence, potentially can result in uncontrolled modification of the membrane composition. Clearly, these effects need to be considered, especially if preparation of miniaturized, potentially disposable internal-solution free sensors is considered. Furthermore, membrane composition changes can occur during the normal operation of sensors—accumulation of species as well as release need to be taken into account, regardless of the construction of sensors used. Issues related to spontaneous changes of membrane composition that can occur during sensor construction, pre-treatment and their operation, seem to be underestimated in the subject literature. The aim of this work is to summarize available data related to potentiometric sensors and highlight the effects that can potentially be important also for other sensors using ion-selective membranes, e.g., optodes or voltammetric sensors. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)
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24 pages, 14297 KiB  
Review
Solid-Contact Ion-Selective Electrodes: Response Mechanisms, Transducer Materials and Wearable Sensors
by Yan Lyu, Shiyu Gan, Yu Bao, Lijie Zhong, Jianan Xu, Wei Wang, Zhenbang Liu, Yingming Ma, Guifu Yang and Li Niu
Membranes 2020, 10(6), 128; https://doi.org/10.3390/membranes10060128 - 23 Jun 2020
Cited by 82 | Viewed by 8835
Abstract
Wearable sensors based on solid-contact ion-selective electrodes (SC-ISEs) are currently attracting intensive attention in monitoring human health conditions through real-time and non-invasive analysis of ions in biological fluids. SC-ISEs have gone through a revolution with improvements in potential stability and reproducibility. The introduction [...] Read more.
Wearable sensors based on solid-contact ion-selective electrodes (SC-ISEs) are currently attracting intensive attention in monitoring human health conditions through real-time and non-invasive analysis of ions in biological fluids. SC-ISEs have gone through a revolution with improvements in potential stability and reproducibility. The introduction of new transducing materials, the understanding of theoretical potentiometric responses, and wearable applications greatly facilitate SC-ISEs. We review recent advances in SC-ISEs including the response mechanism (redox capacitance and electric-double-layer capacitance mechanisms) and crucial solid transducer materials (conducting polymers, carbon and other nanomaterials) and applications in wearable sensors. At the end of the review we illustrate the existing challenges and prospects for future SC-ISEs. We expect this review to provide readers with a general picture of SC-ISEs and appeal to further establishing protocols for evaluating SC-ISEs and accelerating commercial wearable sensors for clinical diagnosis and family practice. Full article
(This article belongs to the Special Issue Advances in Artificial and Biological Membranes: Mechanisms of Ionic Sensitivity, Ion-Sensor Designs and Applications for Ions Measurement)
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