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Siontorou CG, Georgopoulos KN. A Ready-to-Use Metal-Supported Bilayer Lipid Membrane Biosensor for the Detection of Phenol in Water. MEMBRANES 2021; 11:871. [PMID: 34832100 PMCID: PMC8622659 DOI: 10.3390/membranes11110871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022]
Abstract
This work presents a novel metal-supported bilayer lipid membrane (BLM) biosensor built on tyrosinase to quantitate phenol. The detection strategy is based on the enzyme-analyte initial association and not the commonly adopted monitoring of the redox cascade reactions; such an approach has not been proposed in the literature to date and offers many advantages for environmental monitoring with regard to sensitivity, selectivity, reliability and assay simplicity. The phenol sensor developed herein showed good analytical and operational characteristics: the detection limit (signal-to-noise ratio = 3) was 1.24 pg/mL and the sensitivity was 33.45 nA per pg/mL phenol concentration. The shelf life of the tyrosinase sensor was 12 h and the lifetime (in consecutive assays) was 8 h. The sensor was reversible with bathing at pH 8.5 and could be used for eight assay runs in consecutive assays. The validation in real water samples showed that the sensor could reliably detect 2.5 ppb phenol in tap and river water and 6.1 ppb phenol in lake water, without sample pretreatment. The prospects and applicability of the proposed biosensor and the underlying technology are also discussed.
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Affiliation(s)
- Christina G. Siontorou
- Laboratory of Simulation of Industrial Processes, Department of Industrial Management and Technology, University of Piraeus, 80 Karaoli and Dimitriou Str., 18534 Piraeus, Greece;
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Water Pores in Planar Lipid Bilayers at Fast and Slow Rise of Transmembrane Voltage. MEMBRANES 2021; 11:membranes11040263. [PMID: 33916447 PMCID: PMC8067013 DOI: 10.3390/membranes11040263] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 03/28/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022]
Abstract
Basic understanding of the barrier properties of biological membranes can be obtained by studying model systems, such as planar lipid bilayers. Here, we study water pores in planar lipid bilayers in the presence of transmembrane voltage. Planar lipid bilayers were exposed to fast and slow linearly increasing voltage and current signals. We measured the capacitance, breakdown voltage, and rupture time of planar lipid bilayers composed of 1-pamitoyl 2-oleoyl phosphatidylcholine (POPC), 1-pamitoyl 2-oleoyl phosphatidylserine (POPS), and a mixture of both lipids in a 1:1 ratio. Based on the measurements, we evaluated the change in the capacitance of the planar lipid bilayer corresponding to water pores, the radius of water pores at membrane rupture, and the fraction of the area of the planar lipid bilayer occupied by water pores.planar lipid bilayer capacitance, which corresponds to water pores, water pore radius at the membrane rupture, and a fraction of the planar lipid bilayer area occupied by water pores. The estimated pore radii determining the rupture of the planar lipid bilayer upon fast build-up of transmembrane voltage are 0.101 nm, 0.110 nm, and 0.106 nm for membranes composed of POPC, POPS, and POPC:POPS, respectively. The fraction of the surface occupied by water pores at the moment of rupture of the planar lipid bilayer The fraction of an area that is occupied by water pores at the moment of planar lipid bilayer rupture is in the range of 0.1–1.8%.
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Bryant SJ, Garcia A, Clarke RJ, Warr GG. Selective ion transport across a lipid bilayer in a protic ionic liquid. SOFT MATTER 2021; 17:2688-2694. [PMID: 33533359 DOI: 10.1039/d0sm02225j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ionic liquids (ILs) have exhibited enormous potential as electrolytes, designer solvents and reaction media, as well as being surprisingly effective platforms for amphiphile self-assembly and for preserving structure of complex biomolecules. This has led to their exploration as media for long-term biopreservation and in biosensors, for which their viability depends on their ability to sustain both structure and function within complex, multicomponent nanoscale compartments and assemblies. Here we show that a tethered lipid bilayer can be assembled directly in a purely IL environment that retains its structure upon exchange between IL and aqueous buffer, and that the membrane transporter valinomycin can be incorporated so as to retain its functionality and cation selectivity. This paves the way for the development of long-lived, non-aqueous microreactors and sensor assemblies, and demonstrates the potential for complex proteins to retain functionality in non-aqueous, ionic liquid solvents.
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Affiliation(s)
- Saffron J Bryant
- School of Chemistry, The University of Sydney, NSW 2006, Australia and School of Science, RMIT University, Melbourne, Victoria 3001, Australia.
| | - Alvaro Garcia
- School of Chemistry, The University of Sydney, NSW 2006, Australia and School of Life Sciences, University of Technology Sydney, NSW 2007, Australia
| | - Ronald J Clarke
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Gregory G Warr
- School of Chemistry, The University of Sydney, NSW 2006, Australia and University of Sydney Nano Institute, The University of Sydney, NSW 2006, Australia
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Gutiérrez-Pineda E, Andreozzi P, Diamanti E, Anguiano R, Ziolo RF, Moya SE, José Rodríguez-Presa M, Gervasi CA. Effects of valinomycin doping on the electrical and structural properties of planar lipid bilayers supported on polyelectrolyte multilayers. Bioelectrochemistry 2020; 138:107688. [PMID: 33227594 DOI: 10.1016/j.bioelechem.2020.107688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 11/29/2022]
Abstract
Supported Lipid Bilayers (SLBs) on Polyelectrolyte Multilayers (PEMs) have large potential as models for developing sensor devices. SLBs can be designed with receptors and channels, which benefit from the biological environment of the lipid layers, to create a sensing interface for ions and biomarkers. PEMs assembled by the Layer-by-Layer (LBL) technique and used as supports for a lipid bilayer enable an easy integration of the bilayer on almost any surface and device. For electrochemical sensors, LBL assembly enables nanoscale tunable separation of the lipid bilayer from the electrode surface, avoiding undesired effects of the electrode surface on the lipid bilayers. We study the fabrication of valinomycin-doped SLBs on PEMs as a model system for biophysical studies and for selective ion sensing. SLBs are fabricated from dioleoylphosphatidylcholine (DOPC) and dioleoylphosphatidylserine (DOPS) 50:50 vesicles doped with valinomycin, as a K+-selective carrier. SLBs were deposited on electrodes coated with poly(allyl amine hydrochloride) (PAH) and poly(styrene sodium sulfonate) (PSS) multilayers. Lipid bilayer formation was monitored by using Quartz Crystal Microbalance with Dissipation (QCMD) technique and Atomic Force Microscopy (AFM). Electrochemical impedance spectroscopy (EIS) and potentiometric measurements were performed to assess K+ selectivity over other ions and the potential of valinomycin-doped SLBs for K+-sensing.
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Affiliation(s)
- Eduart Gutiérrez-Pineda
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) Universidad Nacional de La Plata - CONICET Sucursal, 4 Casilla de Correo 16, 1900 La Plata, Argentina; Escuela de Ciencias Básicas, Tecnología e Ingeniería, Universidad Nacional Abierta y a Distancia (UNAD), Bucaramanga, Santander, 680001 Colombia.
| | - Patrizia Andreozzi
- Soft Matter Nanotechnology Group, CIC biomaGUNE, Paseo Miramón 182 C, 20009 San Sebastián, Spain
| | - Eleftheria Diamanti
- Soft Matter Nanotechnology Group, CIC biomaGUNE, Paseo Miramón 182 C, 20009 San Sebastián, Spain
| | - Ramiro Anguiano
- Departamento de Materiales Avanzados, Centro de Investigación en Química Aplicada (CIQA), Blvd., Enrique Reyna Hermosillo No.140, 25294 Saltillo, Mexico
| | - Ronald F Ziolo
- Departamento de Materiales Avanzados, Centro de Investigación en Química Aplicada (CIQA), Blvd., Enrique Reyna Hermosillo No.140, 25294 Saltillo, Mexico
| | - Sergio E Moya
- Soft Matter Nanotechnology Group, CIC biomaGUNE, Paseo Miramón 182 C, 20009 San Sebastián, Spain.
| | - María José Rodríguez-Presa
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) Universidad Nacional de La Plata - CONICET Sucursal, 4 Casilla de Correo 16, 1900 La Plata, Argentina
| | - Claudio A Gervasi
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA) Universidad Nacional de La Plata - CONICET Sucursal, 4 Casilla de Correo 16, 1900 La Plata, Argentina; Área Electroquímica, Facultad de Ingeniería, Universidad Nacional de La Plata, calle 1 y 47, 1900 La Plata, Argentina.
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Gál M, Sokolová R, Naumowicz M, Híveš J, Krahulec J. Electrochemical and AFM study of the interaction of recombinant human cathelicidin LL-37 with various supported bilayer lipid membranes. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Khan MS, Dosoky NS, Mustafa G, Patel D, Berdiev B, Williams JD. Electrophysiology of Epithelial Sodium Channel (ENaC) Embedded in Supported Lipid Bilayer Using a Single Nanopore Chip. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:13680-13688. [PMID: 29131643 DOI: 10.1021/acs.langmuir.7b02404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanopore-based technologies are highly adaptable supports for developing label-free sensor chips to characterize lipid bilayers, membrane proteins, and nucleotides. We utilized a single nanopore chip to study the electrophysiology of the epithelial Na+ channel (ENaC) incorporated in supported lipid membrane (SLM). An isolated nanopore was developed inside the silicon cavity followed by fusing large unilamellar vesicles (LUVs) of DPPS (1,2-dipalmitoyl-sn-glycero-3-phosphoserine) and DPPE (1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine) to produce a solvent-free SLM with giga-ohm (GΩ) sealed impedance. The presence and thickness of SLM on the nanopore chip were confirmed using atomic force spectroscopy. The functionality of SLM with and without ENaC was verified in terms of electrical impedance and capacitance by sweeping the frequency from 0.01 Hz to 100 kHz using electrochemical impedance spectroscopy. The nanopore chip exhibits long-term stability for the lipid bilayer before (144 h) and after (16 h) incorporation of ENaC. Amiloride, an inhibitor of ENaC, was utilized at different concentrations to test the integrity of fused ENaC in the lipid bilayer supported on a single nanopore chip. The developed model presents excellent electrical properties and improved mechanical stability of SLM, making this technology a reliable platform to study ion channel electrophysiology.
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Affiliation(s)
- Muhammad Shuja Khan
- Electrical and Computer Engineering Department, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
| | - Noura Sayed Dosoky
- Biotechnology Science and Engineering Program, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
| | - Ghulam Mustafa
- Department of Nuclear Medicine, The State University of New York at Buffalo , Buffalo, New York 14214, United States
| | - Darayas Patel
- Department of Mathematics and Computer Science, Oakwood University , Huntsville, Alabama 35896, United States
| | - Bakhrom Berdiev
- Department of Biomedical Sciences, Nazarbayev University School of Medicine , Astana 010000, Kazakhstan
| | - John Dalton Williams
- Electrical and Computer Engineering Department, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
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Khan MS, Dosoky NS, Patel D, Weimer J, Williams JD. Lipid Bilayer Membrane in a Silicon Based Micron Sized Cavity Accessed by Atomic Force Microscopy and Electrochemical Impedance Spectroscopy. BIOSENSORS 2017; 7:E26. [PMID: 28678160 PMCID: PMC5618032 DOI: 10.3390/bios7030026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/27/2017] [Accepted: 06/30/2017] [Indexed: 02/07/2023]
Abstract
Supported lipid bilayers (SLBs) are widely used in biophysical research to probe the functionality of biological membranes and to provide diagnoses in high throughput drug screening. Formation of SLBs at below phase transition temperature (Tm) has applications in nano-medicine research where low temperature profiles are required. Herein, we report the successful production of SLBs at above-as well as below-the Tm of the lipids in an anisotropically etched, silicon-based micro-cavity. The Si-based cavity walls exhibit controlled temperature which assist in the quick and stable formation of lipid bilayer membranes. Fusion of large unilamellar vesicles was monitored in real time in an aqueous environment inside the Si cavity using atomic force microscopy (AFM), and the lateral organization of the lipid molecules was characterized until the formation of the SLBs. The stability of SLBs produced was also characterized by recording the electrical resistance and the capacitance using electrochemical impedance spectroscopy (EIS). Analysis was done in the frequency regime of 10-2-10⁵ Hz at a signal voltage of 100 mV and giga-ohm sealed impedance was obtained continuously over four days. Finally, the cantilever tip in AFM was utilized to estimate the bilayer thickness and to calculate the rupture force at the interface of the tip and the SLB. We anticipate that a silicon-based, micron-sized cavity has the potential to produce highly-stable SLBs below their Tm. The membranes inside the Si cavity could last for several days and allow robust characterization using AFM or EIS. This could be an excellent platform for nanomedicine experiments that require low operating temperatures.
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Affiliation(s)
- Muhammad Shuja Khan
- Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA.
| | - Noura Sayed Dosoky
- Biotechnology Science and Engineering Program, University of Alabama in Huntsville, Huntsville, AL 35899, USA.
| | - Darayas Patel
- Department of Mathematics and Computer Science, Oakwood University, Huntsville, AL 35896, USA.
| | - Jeffrey Weimer
- Chemistry/Chemical and Materials Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA.
| | - John Dalton Williams
- Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA.
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Electrochemical impedance spectroscopy for black lipid membranes fused with channel protein supported on solid-state nanopore. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:843-852. [DOI: 10.1007/s00249-016-1156-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/25/2016] [Accepted: 04/06/2016] [Indexed: 01/08/2023]
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9
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Naumowicz M, Figaszewski ZA. Pore formation in lipid bilayer membranes made of phosphatidylcholine and cholesterol followed by means of constant current. Cell Biochem Biophys 2013; 66:109-19. [PMID: 23104105 PMCID: PMC3627032 DOI: 10.1007/s12013-012-9459-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This paper describes the application of chronopotentiometry to lipid bilayer research. The experiments were performed on bilayer lipid membranes composed of phosphatidylcholine and cholesterol and formed using the painting technique. Chronopotentiometric (U = f(t)) measurements were used to determine the membrane capacitance, resistance, and breakdown voltage as well as pore conductance and diameter.
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Affiliation(s)
- Monika Naumowicz
- Institute of Chemistry, University of Bialystok, Al. J. Pilsudskiego 11/4, 15-443, Bialystok, Poland.
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10
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Khan MS, Dosoky NS, Williams JD. Engineering lipid bilayer membranes for protein studies. Int J Mol Sci 2013; 14:21561-97. [PMID: 24185908 PMCID: PMC3856022 DOI: 10.3390/ijms141121561] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/13/2013] [Accepted: 10/21/2013] [Indexed: 01/05/2023] Open
Abstract
Lipid membranes regulate the flow of nutrients and communication signaling between cells and protect the sub-cellular structures. Recent attempts to fabricate artificial systems using nanostructures that mimic the physiological properties of natural lipid bilayer membranes (LBM) fused with transmembrane proteins have helped demonstrate the importance of temperature, pH, ionic strength, adsorption behavior, conformational reorientation and surface density in cellular membranes which all affect the incorporation of proteins on solid surfaces. Much of this work is performed on artificial templates made of polymer sponges or porous materials based on alumina, mica, and porous silicon (PSi) surfaces. For example, porous silicon materials have high biocompatibility, biodegradability, and photoluminescence, which allow them to be used both as a support structure for lipid bilayers or a template to measure the electrochemical functionality of living cells grown over the surface as in vivo. The variety of these media, coupled with the complex physiological conditions present in living systems, warrant a summary and prospectus detailing which artificial systems provide the most promise for different biological conditions. This study summarizes the use of electrochemical impedance spectroscopy (EIS) data on artificial biological membranes that are closely matched with previously published biological systems using both black lipid membrane and patch clamp techniques.
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Affiliation(s)
- Muhammad Shuja Khan
- Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA; E-Mail:
| | - Noura Sayed Dosoky
- Biological Sciences Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA; E-Mail:
| | - John Dalton Williams
- Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA; E-Mail:
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Naumowicz M, Figaszewski ZA, Poltorak L. Electrochemical impedance spectroscopy as a useful method for examination of the acid–base equilibria at interface separating electrolyte solution and phosphatidylcholine bilayer. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2012.12.093] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Aliverdieva D, Mamaev D, Snezhkova L, Sholtz C. Evaluation of molecularity of rate-limiting step of pore formation by antimicrobial peptides studied using mitochondria as a biosensor. Toxicol In Vitro 2012; 26:939-49. [DOI: 10.1016/j.tiv.2012.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Revised: 03/09/2012] [Accepted: 04/05/2012] [Indexed: 10/28/2022]
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13
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Makrlík E, Toman P, Vaňura P. Complexation of the cesium cation with nonactin: extraction and DFT study. J Radioanal Nucl Chem 2012. [DOI: 10.1007/s10967-012-1871-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kotyńska J, Petelska AD, Szeremeta M, Niemcunowicz-Janica A, Figaszewski ZA. Changes in surface-charge density of blood cells after sudden unexpected death. J Membr Biol 2012; 245:185-90. [PMID: 22527604 PMCID: PMC3345184 DOI: 10.1007/s00232-012-9428-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 04/01/2012] [Indexed: 12/12/2022]
Abstract
The objective of the investigation was evaluation of postmortem changes of electric charge of human erythrocyte and thrombocyte membranes after sudden unexpected death. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells carried out at various pHs of electrolyte solution. The interactions between both erythrocyte and thrombocyte membranes and electrolyte ions were studied. Values of parameters characterizing the membrane--that is, the total surface concentrations of both acidic and basic groups and their association constants with solution ions--were calculated on the basis of a four-equilibria mathematical model. The model was validated by comparison of these values to experimental data. We established that examined electric properties of the cell membranes are affected by sudden unexpected death. Postmortem processes occurring in the cell membranes can lead to disorders of existing equilibria, which in turn result in changes in values of all the above-mentioned parameters.
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Affiliation(s)
- Joanna Kotyńska
- Institute of Chemistry, University of Bialystok, Al. J. Pilsudskiego 11/4, 15-443 Bialystok, Poland
| | - Aneta D. Petelska
- Institute of Chemistry, University of Bialystok, Al. J. Pilsudskiego 11/4, 15-443 Bialystok, Poland
| | - Michał Szeremeta
- Department of Forensic Medicine, Medical University of Bialystok, Waszyngtona St. 13, 15-230 Bialystok, Poland
| | - Anna Niemcunowicz-Janica
- Department of Forensic Medicine, Medical University of Bialystok, Waszyngtona St. 13, 15-230 Bialystok, Poland
| | - Zbigniew A. Figaszewski
- Institute of Chemistry, University of Bialystok, Al. J. Pilsudskiego 11/4, 15-443 Bialystok, Poland
- Laboratory of Electrochemical Power Sources, Faculty of Chemistry, University of Warsaw, Pasteur St. 1, 02-093 Warsaw, Poland
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Gál M, Sokolová R, Kolivoška V, Morovská Turoňová A, Ambrová M, Híveš J. Metronidazole radical anion formation studied by means of electrochemical impedance spectroscopy. ACTA ACUST UNITED AC 2012. [DOI: 10.1135/cccc2011113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Radiosensitizers belong to the most important class of the cancerostatic drugs. The electrochemical transfer of the first electron to the cytotoxic radiosensitizer Metronidazole (MET) and MET radical anion formation in aprotic medium was studied by means of electrochemical impedance spectroscopy. The heterogeneous electron transfer rate constant for the first reduction of MET (radical anion production) k0 for the redox couple was determined. Similarly, the diffusion coefficient of MET in dimethylformamide was also calculated by impedance measurements using expression for Warburg coefficient and Warburg plot. Moreover, the equivalent circuit for the redox couple MET/MET•– was proposed and its parameters were evaluated using a non-linear least square fitting. Our results, from the electrochemical point of view, also confirm the suitability of MET for the effective treatment of selected types of the cancer.
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Onishi J, Shirai O, Kano K. Electrochemical Elucidation of the Facilitated Ion Transport Across a Bilayer Lipid Membrane in the Presence of Neutral Carrier Compounds. ELECTROANAL 2010. [DOI: 10.1002/elan.200900481] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Agrawal NJ, Weinstein J, Radhakrishnan R. Landscape of finite-temperature equilibrium behaviour of curvature-inducing proteins on a bilayer membrane explored using a linearized elastic free energy model. Mol Phys 2008; 106:1913-1923. [PMID: 21243078 PMCID: PMC3020790 DOI: 10.1080/00268970802365990] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Using a recently developed multiscale simulation methodology, we describe the equilibrium behaviour of bilayer membranes under the influence of curvature-inducing proteins using a linearized elastic free energy model. In particular, we describe how the cooperativity associated with a multitude of protein-membrane interactions and protein diffusion on a membrane-mediated energy landscape elicits emergent behaviour in the membrane phase. Based on our model simulations, we predict that, depending on the density of membrane-bound proteins and the degree to which a single protein molecule can induce intrinsic mean curvature in the membrane, a range of membrane phase behaviour can be observed including two different modes of vesicle-bud nucleation and repressed membrane undulations. A state diagram as a function of experimentally tunable parameters to classify the underlying states is proposed.
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Affiliation(s)
- Neeraj J. Agrawal
- Department of Chemical and Biomolecular Engineering, Philadelphia, PA 19104, USA
| | - Joshua Weinstein
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ravi Radhakrishnan
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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WEINSTEIN J, RADHAKRISHNAN R. 'KMC-TDGL'-a coarse-grained methodology for simulating interfacial dynamics in complex fluids: application to protein-mediated membrane processes. Mol Phys 2006; 104:3653-3666. [PMID: 32724265 PMCID: PMC7386820 DOI: 10.1080/00268970600997580] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In this article, we describe a new multiscale simulation algorithm (which we term the 'KMC-TDGL' method) applicable for the description of equilibrium and dynamic processes associated with a particular class of complex fluids with nanoscale inclusions, namely, biological membranes mediated by membrane-associating and membrane-bound proteins. We adopt a novel strategy of integrating two different phenomenological approaches, namely, a field theoretic (continuum) description for the membrane dynamics given by the time-dependent Ginzburg-Landau equation and a random walk on a discretized lattice description for protein diffusion dynamics. We illustrate that this integrated approach results in a unified description of protein-mediated membrane dynamics.
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Affiliation(s)
| | - R. RADHAKRISHNAN
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia PA 19104, USA
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