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Huang Y, Chandran Suja V, Yang M, Malkovskiy AV, Tandon A, Colom A, Qin J, Fuller GG. Interfacial stresses on droplet interface bilayers using two photon fluorescence lifetime imaging microscopy. J Colloid Interface Sci 2024; 653:1196-1204. [PMID: 37793246 DOI: 10.1016/j.jcis.2023.09.092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 09/06/2023] [Accepted: 09/14/2023] [Indexed: 10/06/2023]
Abstract
HYPOTHESIS Response of lipid bilayers to external mechanical stimuli is an active area of research with implications for fundamental and synthetic cell biology. Developing novel tools for systematically imposing mechanical strains and non-invasively mapping out interfacial (membrane) stress distributions on lipid bilayers can accelerate research in this field. EXPERIMENTS We report a miniature platform to manipulate model cell membranes in the form of droplet interface bilayers (DIBs), and non-invasively measure spatio-temporally resolved interfacial stresses using two photon fluorescence lifetime imaging of an interfacially active molecular flipper (Flipper-TR). We established the effectiveness of the developed framework by investigating interfacial stresses accompanying three key processes associated with DIBs: thin film drainage between lipid monolayer coated droplets, bilayer formation, and bilayer separation. FINDINGS The measurements revealed fundamental aspects of DIBs including the existence of a radially decaying interfacial stress distribution post bilayer formation, and the simultaneous build up and decay of stress respectively at the bilayer corner and center during bilayer separation. Finally, utilizing interfacial rheology measurements and MD simulations, we also reveal that the tested molecular flipper is sensitive to membrane fluidity that changes with interfacial stress - expanding the scientific understanding of how molecular flippers sense stress.
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Affiliation(s)
- Yaoqi Huang
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Vineeth Chandran Suja
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA; School of Engineering and Applied Sciences, Harvard University, MA - 02138, USA.
| | - Menghao Yang
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Andrey V Malkovskiy
- Carnegie Institute for Science, Department of Plant Biology, Stanford CA 94305, USA
| | - Arnuv Tandon
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Adai Colom
- Biofisika Institute (CSIC, UPV/EHU), 48940 Leioa, Spain; Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, Campus Universitario, University of the Basque Country (UPV/EHU), 48940 Leioa, Spain
| | - Jian Qin
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Gerald G Fuller
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
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Lolicato F, Saleppico R, Griffo A, Meyer A, Scollo F, Pokrandt B, Müller HM, Ewers H, Hähl H, Fleury JB, Seemann R, Hof M, Brügger B, Jacobs K, Vattulainen I, Nickel W. Cholesterol promotes clustering of PI(4,5)P2 driving unconventional secretion of FGF2. J Biophys Biochem Cytol 2022; 221:213511. [PMID: 36173379 PMCID: PMC9526255 DOI: 10.1083/jcb.202106123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/22/2022] [Accepted: 08/30/2022] [Indexed: 11/22/2022] Open
Abstract
FGF2 is a cell survival factor involved in tumor-induced angiogenesis that is secreted through an unconventional secretory pathway based upon direct protein translocation across the plasma membrane. Here, we demonstrate that both PI(4,5)P2-dependent FGF2 recruitment at the inner plasma membrane leaflet and FGF2 membrane translocation into the extracellular space are positively modulated by cholesterol in living cells. We further revealed cholesterol to enhance FGF2 binding to PI(4,5)P2-containing lipid bilayers. Based on extensive atomistic molecular dynamics (MD) simulations and membrane tension experiments, we proposed cholesterol to modulate FGF2 binding to PI(4,5)P2 by (i) increasing head group visibility of PI(4,5)P2 on the membrane surface, (ii) increasing avidity by cholesterol-induced clustering of PI(4,5)P2 molecules triggering FGF2 oligomerization, and (iii) increasing membrane tension facilitating the formation of lipidic membrane pores. Our findings have general implications for phosphoinositide-dependent protein recruitment to membranes and explain the highly selective targeting of FGF2 toward the plasma membrane, the subcellular site of FGF2 membrane translocation during unconventional secretion of FGF2.
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Affiliation(s)
- Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg, Germany.,Department of Physics, University of Helsinki, Helsinki, Finland
| | | | - Alessandra Griffo
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Annalena Meyer
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Federica Scollo
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Bianca Pokrandt
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | | | - Helge Ewers
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Hendrik Hähl
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | | | - Ralf Seemann
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Martin Hof
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Britta Brügger
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Karin Jacobs
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Max Planck School Matter to Life, Heidelberg, Germany
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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Huang Y, Fuller G, Chandran Suja V. Physicochemical characteristics of droplet interface bilayers. Adv Colloid Interface Sci 2022; 304:102666. [PMID: 35429720 DOI: 10.1016/j.cis.2022.102666] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 11/01/2022]
Abstract
Droplet interface bilayer (DIB) is a lipid bilayer formed when two lipid monolayer-coated aqueous droplets are brought in contact within an oil phase. DIBs, especially post functionalization, are a facile model system to study the biophysics of the cell membrane. Continued advances in enhancing and functionalizing DIBs to be a faithful cell membrane mimetic requires a deep understanding of the physicochemical characteristics of droplet interface bilayers. In this review, we provide a comprehensive overview of the current scientific understanding of DIB characteristics starting with the key experimental frameworks for DIB generation, visualization and functionalization. Subsequently we report experimentally measured physical, electrical and transport characteristics of DIBs across physiologically relevant lipids. Advances in simulations and mathematical modelling of DIBs are also discussed, with an emphasis on revealing principles governing the key physicochemical characteristics. Finally, we conclude the review with important outstanding questions in the field.
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Zhang H, Ma H, Yang X, Fan L, Tian S, Niu R, Yan M, Zheng M, Zhang S. Cell Fusion-Related Proteins and Signaling Pathways, and Their Roles in the Development and Progression of Cancer. Front Cell Dev Biol 2022; 9:809668. [PMID: 35178400 PMCID: PMC8846309 DOI: 10.3389/fcell.2021.809668] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/22/2021] [Indexed: 12/16/2022] Open
Abstract
Cell fusion is involved in many physiological and pathological processes, including gamete binding, and cancer development. The basic processes of cell fusion include membrane fusion, cytoplasmic mixing, and nuclear fusion. Cell fusion is regulated by different proteins and signaling pathways. Syncytin-1, syncytin-2, glial cell missing 1, galectin-1 and other proteins (annexins, myomaker, myomerger etc.) involved in cell fusion via the cyclic adenosine-dependent protein kinase A, mitogen-activated protein kinase, wingless/integrase-1, and c-Jun N-terminal kinase signaling pathways. In the progression of malignant tumors, cell fusion is essential during the organ-specific metastasis, epithelial-mesenchymal transformation, the formation of cancer stem cells (CSCs), cancer angiogenesis and cancer immunity. In addition, diploid cells can be induced to form polyploid giant cancer cells (PGCCs) via cell fusion under many kinds of stimuli, including cobalt chloride, chemotherapy, radiotherapy, and traditional Chinese medicine. PGCCs have CSC-like properties, and the daughter cells derived from PGCCs have a mesenchymal phenotype and exhibit strong migration, invasion, and proliferation abilities. Therefore, exploring the molecular mechanisms of cell fusion can enable us better understand the development of malignant tumors. In this review, the basic process of cell fusion and its significance in cancer is discussed.
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Affiliation(s)
- Hao Zhang
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Hong Ma
- Tianjin Union Medical Center, Nankai University, Tianjin, China
| | - Xiaohui Yang
- Nankai University School of Medicine, Nankai University, Tianjin, China
| | - Linlin Fan
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Shifeng Tian
- Graduate School, Tianjin Medical University, Tianjin, China
| | - Rui Niu
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Man Yan
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Minying Zheng
- Tianjin Union Medical Center, Nankai University, Tianjin, China
| | - Shiwu Zhang
- Tianjin Union Medical Center, Nankai University, Tianjin, China
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Linklater DP, Baulin VA, Le Guével X, Fleury JB, Hanssen E, Nguyen THP, Juodkazis S, Bryant G, Crawford RJ, Stoodley P, Ivanova EP. Antibacterial Action of Nanoparticles by Lethal Stretching of Bacterial Cell Membranes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2005679. [PMID: 33179362 DOI: 10.1002/adma.202005679] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/05/2020] [Indexed: 06/11/2023]
Abstract
It is commonly accepted that nanoparticles (NPs) can kill bacteria; however, the mechanism of antimicrobial action remains obscure for large NPs that cannot translocate the bacterial cell wall. It is demonstrated that the increase in membrane tension caused by the adsorption of NPs is responsible for mechanical deformation, leading to cell rupture and death. A biophysical model of the NP-membrane interactions is presented which suggests that adsorbed NPs cause membrane stretching and squeezing. This general phenomenon is demonstrated experimentally using both model membranes and Pseudomonas aeruginosa and Staphylococcus aureus, representing Gram-positive and Gram-negative bacteria. Hydrophilic and hydrophobic quasi-spherical and star-shaped gold (Au)NPs are synthesized to explore the antibacterial mechanism of non-translocating AuNPs. Direct observation of nanoparticle-induced membrane tension and squeezing is demonstrated using a custom-designed microfluidic device, which relieves contraction of the model membrane surface area and eventual lipid bilayer collapse. Quasi-spherical nanoparticles exhibit a greater bactericidal action due to a higher interactive affinity, resulting in greater membrane stretching and rupturing, corroborating the theoretical model. Electron microscopy techniques are used to characterize the NP-bacterial-membrane interactions. This combination of experimental and theoretical results confirm the proposed mechanism of membrane-tension-induced (mechanical) killing of bacterial cells by non-translocating NPs.
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Affiliation(s)
- Denver P Linklater
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
- Opical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia
| | - Vladimir A Baulin
- Department d'Enginyeria Quimica, Universitat Rovira i Virgili, 26 Av. dels Paisos Catalans, Tarragona, 43007, Spain
| | - Xavier Le Guével
- Insitute for Advanced Biosciences, University Grenoble-Alpes, Allee des Alpes, La Tronche, 38700, France
| | - Jean-Baptiste Fleury
- Experimental Physics and Center for Biophysics, Saarland University, Saarbrücken, 66123, Germany
| | - Eric Hanssen
- Ian Holmes Imaging Centre, Bio21 Institute, University of Melbourne, 30 Flemington Rd, Parkville, Victoria, 3010, Australia
| | - The Hong Phong Nguyen
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, 700000, Vietnam
| | - Saulius Juodkazis
- Opical Sciences Centre, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia
| | - Gary Bryant
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
| | - Russell J Crawford
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
| | - Paul Stoodley
- Infectious Diseases Institute, The Ohio State University, 716 Biomedical Research Tower, 460 West 12th Avenue, Columbus, OH, 43210, USA
- National Centre for Advanced Tribology at Southampton (nCATS), National Biofilm Innovation Centre (NBIC), Mechanical Engineering, University of Southampton, Southampton, SO17 1Bj, UK
| | - Elena P Ivanova
- School of Science, RMIT University, P.O. Box 2476, Melbourne, Victoria, 3001, Australia
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Tawfik H, Puza S, Seemann R, Fleury JB. Transport Properties of Gramicidin A Ion Channel in a Free-Standing Lipid Bilayer Filled With Oil Inclusions. Front Cell Dev Biol 2020; 8:531229. [PMID: 33015051 PMCID: PMC7498540 DOI: 10.3389/fcell.2020.531229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 08/14/2020] [Indexed: 11/13/2022] Open
Abstract
Ion channels are key proteins in mammalian cell membranes. They have a central role in the physiology of excitable cells such as neurons, muscle, and heart cells. They also play a crucial role in kidney physiology. The gramicidin ion channel is one of the most studied ion channels, in particular it was intensively employed to investigate the lipid–protein interactions in model cell membranes. For example, even though the sequence of gramicidin is extremely hydrophobic, its motion is impaired in membrane bilayer, i.e., it does not rapidly flip to the other membrane leaflet, and low channel activity were observed when gramicidin is added asymmetrically to only one leaflet of a model cell membrane. In this article, we study the transport properties of gramicidin channel in a heterogeneous model membrane. Using microfluidics, we are forming freestanding bilayers as model cell membranes including heterogeneous domains that are created by oil inclusions. The presence of oil inclusions is then demonstrated by measuring the bilayer capacity via a patch-clamp amplifier and fluorescent confocal inspection. Based on electrophysiological and optical measurements Gramicidin A (gA) ion channels are dispersed into the buffer phases on both side of the formed lipid bilayer and insert spontaneously into the bilayer upon formation. The presence of functional Gramicidin A is then demonstrated by measuring conductivity signals. Based on electrophysiological and optical measurements, we explore the consequence of the presence of these oil inclusions on the functionality of incorporated gA ion channels. For low oil concentration, we measure a decrease of gA transport properties due to the reduction of the bilayer tension. For large oil concentration, we measure a saturation of gA transport properties due to an increase of the bilayer thickness.
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Affiliation(s)
- Harvey Tawfik
- Experimental Physics and Center for Biophysics, Universität des Saarlandes, Saarbrücken, Germany
| | - Sevde Puza
- Experimental Physics and Center for Biophysics, Universität des Saarlandes, Saarbrücken, Germany
| | - Ralf Seemann
- Experimental Physics and Center for Biophysics, Universität des Saarlandes, Saarbrücken, Germany
| | - Jean-Baptiste Fleury
- Experimental Physics and Center for Biophysics, Universität des Saarlandes, Saarbrücken, Germany
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7
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Khangholi N, Seemann R, Fleury JB. Simultaneous measurement of surface and bilayer tension in a microfluidic chip. BIOMICROFLUIDICS 2020; 14:024117. [PMID: 32549923 PMCID: PMC7188485 DOI: 10.1063/1.5137810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/10/2020] [Indexed: 06/11/2023]
Abstract
Freestanding lipid bilayers are one of the most used model systems to mimic biological cell membranes. To form an unsupported bilayer, we employ two aqueous fingers in a microfluidic chip surrounded by an oily phase that contains lipids. Upon pushing two aqueous fingers forward, their interface becomes decorated with a lipid monolayer and eventually zip to form a bilayer when the monolayers have nanoscopic contact with each other. Using this straightforward approach, the quick and easy bilayer formation is facilitated by oil draining into the microfluidic device material consisting of polydimethylsiloxane. However, the oil drainage limits the lifetime of a bilayer to about 1 h. We demonstrate that this drainage can be managed, resulting in superior bilayer stability and an increased lifetime of several hours when using a pressure-controlled system. Applying different pressures to the aqueous fingers in the microfluidic chip, the formed bilayer can even be bent to a desired curvature. Extracting the contact angle and the resulting curvature of the bilayer region, for a given applied pressure difference, both the bilayer tension and the surface tension of each lipid monolayer can be derived from a single experiment using the Young Laplace pressure equation.
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Affiliation(s)
- Navid Khangholi
- Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
| | - Ralf Seemann
- Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
| | - Jean-Baptiste Fleury
- Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany
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8
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Guo Y, Werner M, Fleury JB, Baulin VA. Unexpected Cholesterol-Induced Destabilization of Lipid Membranes near Transmembrane Carbon Nanotubes. PHYSICAL REVIEW LETTERS 2020; 124:038001. [PMID: 32031854 DOI: 10.1103/physrevlett.124.038001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Indexed: 06/10/2023]
Abstract
Cholesterol is a crucial component of mammalian cell membranes that takes part in many vital processes. It is generally accepted that cholesterol stabilizes the membrane and induces transitions into ordered states. In contrast to expectations, we demonstrate that cholesterol can destabilize the membrane by creating a nanodomain around a perpendicularly embedded ultrashort carbon nanotube (CNT), and we show that cholesterol triggers the translocation of an ultrashort CNT through the cell membrane. Using atomistic simulations, we report the existence of a nanoscale domain around an ultrashort carbon nanotube within a crossover distance of 0.9 nm from the surface of the nanotube, where the properties of the bilayer are different from the bulk: the domain is characterized by increased fluctuations, increased thickness, and increased order of the lipids with respect to the bulk. Cholesterol decreases the thickness and order of lipids and increases the fluctuations with respect to a pure lipid bilayer. Experimentally, we confirm that cholesterol nanodomains provoke spontaneous translocation of nanotubes through a lipid bilayer even for low membrane tensions. A specially designed microfluidic device allows us to trace the kinetic pathway of the translocation process and establish the threshold cholesterol concentration of 20% for translocation. The reported nanoscale cholesterol-induced membrane restructuring near the ultrashort CNT in lipid membranes enables precise control and specific targeting of a membrane using cholesterol. As an example, it may allow for specific targeting between cholesterol-rich mammalian cells and cholesterol-poor bacterial cells.
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Affiliation(s)
- Yachong Guo
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China
| | - Marco Werner
- Leibniz-Institut für Polymerforschung Dresden, Hohe Strasse 6, 01069 Dresden, Germany
| | - Jean Baptiste Fleury
- Universitat des Saarlandes, Experimental Physics and Center for Biophysics, 66123 Saarbruecken, Germany
| | - Vladimir A Baulin
- Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, 26 Avinguda dels Paisos Catalans, 43007 Tarragona, Spain
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Projective mechanisms subtending real world phenomena wipe away cause effect relationships. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 151:1-13. [PMID: 31838044 DOI: 10.1016/j.pbiomolbio.2019.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/16/2019] [Accepted: 12/10/2019] [Indexed: 01/11/2023]
Abstract
Causal relationships lie at the very core of scientific description of biophysical phenomena. Nevertheless, observable facts involving changes in system shape, dimension and symmetry may elude simple cause and effect inductive explanations. Here we argue that numerous physical and biological phenomena such as chaotic dynamics, symmetry breaking, long-range collisionless neural interactions, zero-valued energy singularities, and particle/wave duality can be accounted for in terms of purely topological mechanisms devoid of causality. We illustrate how simple topological claims, seemingly far away from scientific inquiry (e.g., "given at least some wind on Earth, there must at all times be a cyclone or anticyclone somewhere"; "if one stirs to dissolve a lump of sugar in a cup of coffee, it appears there is always a point without motion"; "at any moment, there is always a pair of antipodal points on the Earth's surface with equal temperatures and barometric pressures") reflect the action of non-causal topological rules. To do so, we introduce some fundamental topological tools and illustrate how phenomena such as double slit experiments, cellular mechanisms and some aspects of brain function can be explained in terms of geometric projections and mappings, rather than local physical effects. We conclude that unavoidable, passive, spontaneous topological modifications may lead to novel functional biophysical features, independent of exerted physical forces, thermodynamic constraints, temporal correlations and probabilistic a priori knowledge of previous cases.
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Arturo T. Towards dewetting monoclonal antibodies for therapeutical purposes. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 150:153-159. [PMID: 31525385 DOI: 10.1016/j.pbiomolbio.2019.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/22/2019] [Accepted: 09/07/2019] [Indexed: 12/30/2022]
Abstract
Dewetting transition - a concept borrowed from fluid mechanics - is a physiological process that takes place inside the hydrophobic pores of ion channels. This transient phenomenon causes a metastable state that forbids water molecules to cross microscopic receptor cavities. This leads to a decreased conductance, a closure of the pore and, subsequently, severe impairment of cellular performance. We suggest that artificially-provoked dewetting transition in ion channel hydrophobic pores might stand for a molecular candidate to erase detrimental organisms, such as viruses, bacteria, and cancer cells. We describe a novel type of high-affinity monoclonal antibody, that: a) targets specific trans-membrane receptor structures of harmful or redundant cells; b) is equipped with lipophilic and/or hydrophobic fragments that prevent physiological water flow inside ion channels. Therefore, we achieve an artificial dewetting transition inside receptor cavities, that causes discontinuity within transmembrane ionic flows, channel blockage, and subsequent damage of morbid cells. As an example, we describe dewetting monoclonal antibodies that target the M2 channel of the Influenza A virus: they might prevent water from entering pores thus leading to virion impairment.
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Affiliation(s)
- Tozzi Arturo
- Center for Nonlinear Science, Department of Physics, University of North Texas, 1155 Union Circle, #311427, Denton, TX, 76203-5017, USA.
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11
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Guo Y, Werner M, Seemann R, Baulin VA, Fleury JB. Tension-Induced Translocation of an Ultrashort Carbon Nanotube through a Phospholipid Bilayer. ACS NANO 2018; 12:12042-12049. [PMID: 30452223 DOI: 10.1021/acsnano.8b04657] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Increasing awareness of bioeffects and toxicity of nanomaterials interacting with cells puts in focus the mechanisms by which nanomaterials can cross lipid membranes. Apart from well-discussed energy-dependent endocytosis for large objects and passive diffusion through membranes by solute molecules, other translocation mechanisms based on physical principles can exist. We show the importance of membrane tension on the translocation through lipid bilayers of ultrashort carbon nanotubes (USCNTs). By using a combination of a microfluidic setup and single chain mean field (SCMF) theory, we observed that, under membrane tension, USCNT inserted into a lipid bilayer may spontaneously nucleate an unstable local pore, allowing it to escape from the bilayer. We demonstrated that stretching of the membrane is essential for triggering this mechanism of translocation, and no translocation is observed at low membrane tension. For this purpose, a quantitative analysis of the kinetic pathway associated with USCNT translocation induced by tension was performed in a specially designed microfluidic device, simultaneously combining optical fluorescence microscopy and electrophysiological measurements. An important outcome of these findings is the identification of the way to control the nanomaterial translocation through the lipid bilayer by membrane tension that can be useful in many practical applications.
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Affiliation(s)
- Yachong Guo
- National Laboratory of Solid State Microstructure, Department of Physics , Nanjing University , Nanjing 210093 , China
- Departament d'Enginyeria Quimica , Universitat Rovira i Virgili , 26 Av. dels Paisos Catalans , 43007 Tarragona , Spain
| | - Marco Werner
- Leibniz-Institut für Polymerforschung Dresden e.V. , Hohe Straße 6 , 01069 Dresden , Germany
| | - Ralf Seemann
- Universität des Saarlandes , Experimental Physics and Center for Biophysics , 66123 Saarbrücken , Germany
| | - Vladimir A Baulin
- Departament d'Enginyeria Quimica , Universitat Rovira i Virgili , 26 Av. dels Paisos Catalans , 43007 Tarragona , Spain
| | - Jean-Baptiste Fleury
- Universität des Saarlandes , Experimental Physics and Center for Biophysics , 66123 Saarbrücken , Germany
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12
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Hähl H, Vargas JN, Jung M, Griffo A, Laaksonen P, Lienemann M, Jacobs K, Seemann R, Fleury JB. Adhesion Properties of Freestanding Hydrophobin Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:8542-8549. [PMID: 29886739 DOI: 10.1021/acs.langmuir.8b00575] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hydrophobins are a family of small-sized proteins featuring a distinct hydrophobic patch on the protein's surface, rendering them amphiphilic. This particularity allows hydrophobins to self-assemble into monolayers at any hydrophilic/hydrophobic interface. Moreover, stable pure protein bilayers can be created from two interfacial hydrophobin monolayers by contacting either their hydrophobic or their hydrophilic sides. In this study, this is achieved via a microfluidic approach, in which also the bilayers' adhesion energy can be determined. This enables us to study the origin of the adhesion of hydrophobic and hydrophilic core bilayers made from the class II hydrophobins HFBI and HFBII. Using different fluid media in this setup and introducing genetically modified variants of the HFBI molecule, the different force contributions to the adhesion of the bilayer sheets are studied. It was found that in the hydrophilic contact situation, the adhesive interaction was higher than that in the hydrophobic contact situation and could be even enhanced by reducing the contributions of electrostatic interactions. This effect indicates that the van der Waals interaction is the dominant contribution that explains the stability of the observed bilayers.
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Affiliation(s)
- Hendrik Hähl
- Department of Experimental Physics and Center for Biophysics , Saarland University , D-66123 Saarbrücken , Germany
| | - Jose Nabor Vargas
- Department of Experimental Physics and Center for Biophysics , Saarland University , D-66123 Saarbrücken , Germany
| | - Michael Jung
- Department of Experimental Physics and Center for Biophysics , Saarland University , D-66123 Saarbrücken , Germany
| | - Alessandra Griffo
- Department of Bioproducts and Biosystems BIO2 , Aalto University , P.O. Box 16100, 00076 Aalto , Finland
| | - Päivi Laaksonen
- Department of Bioproducts and Biosystems BIO2 , Aalto University , P.O. Box 16100, 00076 Aalto , Finland
| | - Michael Lienemann
- VTT Technical Research Centre of Finland Ltd. , Tietotie 2 , 02150 Espoo , Finland
| | - Karin Jacobs
- Department of Experimental Physics and Center for Biophysics , Saarland University , D-66123 Saarbrücken , Germany
| | - Ralf Seemann
- Department of Experimental Physics and Center for Biophysics , Saarland University , D-66123 Saarbrücken , Germany
| | - Jean-Baptiste Fleury
- Department of Experimental Physics and Center for Biophysics , Saarland University , D-66123 Saarbrücken , Germany
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Lopez M, Denver J, Evangelista SE, Armetta A, Di Domizio G, Lee S. Effects of Acyl Chain Unsaturation on Activation Energy of Water Permeability across Droplet Bilayers of Homologous Monoglycerides: Role of Cholesterol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:2147-2157. [PMID: 29323917 DOI: 10.1021/acs.langmuir.7b03590] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Cholesterol is an important component of total lipid in mammalian cellular membranes; hence, the knowledge of its association with lipid bilayer membranes will be essential to understanding membrane structure and function. A droplet interface bilayer (DIB) provides a convenient and reliable platform through which values for permeability coefficient and activation energy of water transport across the membrane can be extracted. In this study, we investigated the effect of acyl chain structure in amphiphilic monoglycerides on the permeability of water across DIB membranes composed of cholesterol and these monoglycerides, where the acyl chain length, number of double bonds, and the position of double bond are varied systematically along the acyl chains. To elucidate the role of cholesterol in these membranes, we investigated its influence on water permeability and associated activation energies at two different cholesterol concentrations. Our systematic studies show dramatic sensitivity and selectivity of specific interaction of cholesterol with the monoglyceride bilayer having structural variations in acyl chain compositions. Our findings allow us to delineate the exquisite interplay between membrane properties and structural components and understand the balanced contribution of each.
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Affiliation(s)
- Maria Lopez
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Jacqueline Denver
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Sue Ellen Evangelista
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Alessandra Armetta
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Gabriella Di Domizio
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
| | - Sunghee Lee
- Department of Chemistry, Iona College , 715 North Avenue, New Rochelle, New York 10801, United States
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14
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Stefanic M, Ward K, Tawfik H, Seemann R, Baulin V, Guo Y, Fleury JB, Drouet C. Apatite nanoparticles strongly improve red blood cell cryopreservation by mediating trehalose delivery via enhanced membrane permeation. Biomaterials 2017. [DOI: 10.1016/j.biomaterials.2017.06.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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Han J, Pluhackova K, Böckmann RA. The Multifaceted Role of SNARE Proteins in Membrane Fusion. Front Physiol 2017; 8:5. [PMID: 28163686 PMCID: PMC5247469 DOI: 10.3389/fphys.2017.00005] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/04/2017] [Indexed: 12/28/2022] Open
Abstract
Membrane fusion is a key process in all living organisms that contributes to a variety of biological processes including viral infection, cell fertilization, as well as intracellular transport, and neurotransmitter release. In particular, the various membrane-enclosed compartments in eukaryotic cells need to exchange their contents and communicate across membranes. Efficient and controllable fusion of biological membranes is known to be driven by cooperative action of SNARE proteins, which constitute the central components of the eukaryotic fusion machinery responsible for fusion of synaptic vesicles with the plasma membrane. During exocytosis, vesicle-associated v-SNARE (synaptobrevin) and target cell-associated t-SNAREs (syntaxin and SNAP-25) assemble into a core trans-SNARE complex. This complex plays a versatile role at various stages of exocytosis ranging from the priming to fusion pore formation and expansion, finally resulting in the release or exchange of the vesicle content. This review summarizes current knowledge on the intricate molecular mechanisms underlying exocytosis triggered and catalyzed by SNARE proteins. Particular attention is given to the function of the peptidic SNARE membrane anchors and the role of SNARE-lipid interactions in fusion. Moreover, the regulatory mechanisms by synaptic auxiliary proteins in SNARE-driven membrane fusion are briefly outlined.
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Affiliation(s)
- Jing Han
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China; Computational Biology, Department of Biology, Friedrich-Alexander Universität Erlangen-NürnbergErlangen, Germany
| | - Kristyna Pluhackova
- Computational Biology, Department of Biology, Friedrich-Alexander Universität Erlangen-Nürnberg Erlangen, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander Universität Erlangen-Nürnberg Erlangen, Germany
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16
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Hähl H, Vargas JN, Griffo A, Laaksonen P, Szilvay G, Lienemann M, Jacobs K, Seemann R, Fleury JB. Pure Protein Bilayers and Vesicles from Native Fungal Hydrophobins. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1602888. [PMID: 27740699 DOI: 10.1002/adma.201602888] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/16/2016] [Indexed: 05/21/2023]
Abstract
Pure protein bilayers and vesicles are formed using the native, fungal hydrophobin HFBI. Bilayers with hydrophobic (red) and hydrophilic (blue) core are produced and, depending on the type of core, vesicles in water, oily media, and even in air can be created using microfluidic jetting. Vesicles in water are even able to incorporate functional gramicidin A pores.
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Affiliation(s)
- Hendrik Hähl
- Department of Experimental Physics, Saarland University, 66123, Saarbrücken, Germany
| | - Jose Nabor Vargas
- Department of Experimental Physics, Saarland University, 66123, Saarbrücken, Germany
| | - Alessandra Griffo
- Department of Experimental Physics, Saarland University, 66123, Saarbrücken, Germany
- Department of Materials Science, Aalto University, P. O. Box 16100, 00076, Aalto, Finland
| | - Päivi Laaksonen
- Department of Materials Science, Aalto University, P. O. Box 16100, 00076, Aalto, Finland
| | - Géza Szilvay
- VTT Technical Research Centre of Finland Ltd, Tietotie 2, 02150, Espoo, Finland
| | - Michael Lienemann
- VTT Technical Research Centre of Finland Ltd, Tietotie 2, 02150, Espoo, Finland
| | - Karin Jacobs
- Department of Experimental Physics, Saarland University, 66123, Saarbrücken, Germany
| | - Ralf Seemann
- Department of Experimental Physics, Saarland University, 66123, Saarbrücken, Germany
| | - Jean-Baptiste Fleury
- Department of Experimental Physics, Saarland University, 66123, Saarbrücken, Germany
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17
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Barlow NE, Bolognesi G, Flemming AJ, Brooks NJ, Barter LMC, Ces O. Multiplexed droplet Interface bilayer formation. LAB ON A CHIP 2016; 16:4653-4657. [PMID: 27831583 DOI: 10.1039/c6lc01011c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We present a simple method for the multiplexed formation of droplet interface bilayers (DIBs) using a mechanically operated linear acrylic chamber array. To demonstrate the functionality of the chip design, a lipid membrane permeability assay is performed. We show that multiple, symmetric DIBs can be created and separated using this robust low-cost approach.
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Affiliation(s)
- Nathan E Barlow
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK. and Institute of Chemical Biology, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK.
| | - Guido Bolognesi
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK. and Institute of Chemical Biology, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK.
| | - Anthony J Flemming
- Institute of Chemical Biology, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK. and Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK.
| | - Nicholas J Brooks
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK. and Institute of Chemical Biology, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK.
| | - Laura M C Barter
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK. and Institute of Chemical Biology, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK.
| | - Oscar Ces
- Department of Chemistry, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK. and Institute of Chemical Biology, Imperial College London, Exhibition Road, South Kensington, London, SW7 2AZ, UK.
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18
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Guo Y, Terazzi E, Seemann R, Fleury JB, Baulin VA. Direct proof of spontaneous translocation of lipid-covered hydrophobic nanoparticles through a phospholipid bilayer. SCIENCE ADVANCES 2016; 2:e1600261. [PMID: 27847863 PMCID: PMC5099980 DOI: 10.1126/sciadv.1600261] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 09/29/2016] [Indexed: 05/21/2023]
Abstract
Hydrophobic nanoparticles introduced into living systems may lead to increased toxicity, can activate immune cells, or can be used as nanocarriers for drug or gene delivery. It is generally accepted that small hydrophobic nanoparticles are blocked by lipid bilayers and accumulate in the bilayer core, whereas big nanoparticles can only penetrate cells through slow energy-dependent processes, such as endocytosis, lasting minutes. In contrast to expectations, we demonstrate that lipid-covered hydrophobic nanoparticles may translocate through lipid membranes by direct penetration within milliseconds. We identified the threshold size for translocation: nanoparticles with diameters smaller than 5 nm stay trapped in the bilayer, whereas those with diameters larger than 5 nm insert into the bilayer, opening pores in the bilayer. The direct proof of this size-dependent translocation was provided by an in situ observation of a single event of a nanoparticle quitting the bilayer. This was achieved with a specially designed microfluidic device combining optical fluorescence microscopy with simultaneous electrophysiological measurements. A quantitative analysis of the kinetic pathway of a single nanoparticle translocation event demonstrated that the translocation is irreversible and that the nanoparticle can translocate only once. This newly discovered one-way translocation mechanism provides numerous opportunities for biotechnological applications, ranging from targeted biomaterial elimination and/or delivery to precise and controlled trapping of nanoparticles.
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Affiliation(s)
- Yachong Guo
- Departament d’Enginyeria Química, Universitat Rovira i Virgili, 26 Avinguda dels Països Catalans, 43007 Tarragona, Spain
| | - Emmanuel Terazzi
- Department of Inorganic and Analytical Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Ralf Seemann
- Experimental Physics, Universität des Saarlandes, 66123 Saarbrücken, Germany
| | | | - Vladimir A. Baulin
- Departament d’Enginyeria Química, Universitat Rovira i Virgili, 26 Avinguda dels Països Catalans, 43007 Tarragona, Spain
- Corresponding author.
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19
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Tozzi A, Flå T, Peters JF. Building a minimum frustration framework for brain functions over long time scales. J Neurosci Res 2016; 94:702-16. [PMID: 27114266 DOI: 10.1002/jnr.23748] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/14/2016] [Accepted: 03/28/2016] [Indexed: 01/02/2023]
Abstract
The minimum frustration principle (MFP) is a computational approach stating that, over the long time scales of evolution, proteins' free energy decreases more than expected by thermodynamical constraints as their amino acids assume conformations progressively closer to the lowest energetic state. This Review shows that this general principle, borrowed from protein folding dynamics, can also be fruitfully applied to nervous function. Highlighting the foremost role of energetic requirements, macromolecular dynamics, and above all intertwined time scales in brain activity, the MFP elucidates a wide range of mental processes from sensations to memory retrieval. Brain functions are compared with trajectories that, over long nervous time scales, are attracted toward the low-energy bottom of funnel-like structures characterized by both robustness and plasticity. We discuss how the principle, derived explicitly from evolution and selection of a funneling structure from microdynamics of contacts, is unlike other brain models equipped with energy landscapes, such as the Bayesian and free energy principles and the Hopfield networks. In summary, we make available a novel approach to brain function cast in a biologically informed fashion, with the potential to be operationalized and assessed empirically. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Arturo Tozzi
- Center for Nonlinear Science, University of North Texas, Denton, Texas
| | - Tor Flå
- Department of Mathematics and Statistics, Centre for Theoretical and Computational Chemistry, UiT, The Arctic University of Norway, Tromsø, Norway
| | - James F Peters
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba, Canada.,Department of Mathematics, Adıyaman University, Adıyaman, Turkey
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