1
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Hall SCL, Hardy DJ, Bragginton ÉC, Johnston H, Onose T, Holyfield R, Sridhar P, Knowles TJ, Clifton LA. Distance tuneable integral membrane protein containing floating bilayers via in situ directed self-assembly. NANOSCALE 2024; 16:13503-13515. [PMID: 38940744 PMCID: PMC11256219 DOI: 10.1039/d3nr04622b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 06/18/2024] [Indexed: 06/29/2024]
Abstract
Model membranes allow for structural and biophysical studies on membrane biochemistry at the molecular level, albeit on systems of reduced complexity which can limit biological accuracy. Floating supported bilayers offer a means of producing planar lipid membrane models not adhered to a surface, which allows for improved accuracy compared to other model membranes. Here we communicate the incorporation of an integral membrane protein complex, the multidomain β-barrel assembly machinery (Bam), into our recently developed in situ self-assembled floating supported bilayers. Using neutron reflectometry and quartz crystal microbalance measurements we show this sample system can be fabricated using a two-step self-assembly process. We then demonstrate the complexity of the model membrane and tuneability of the membrane-to-surface distance using changes in the salt concentration of the bulk solution. Results demonstrate an easily fabricated, biologically accurate and tuneable membrane assay system which can be utilized for studies on integral membrane proteins within their native lipid matrix.
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Affiliation(s)
- Stephen C L Hall
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 OQX, UK.
| | - David J Hardy
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Éilís C Bragginton
- Electron Bio-Imaging Centre (eBIC), Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, OX11 0DE, UK
| | - Hannah Johnston
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Tudor Onose
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Rachel Holyfield
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Pooja Sridhar
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Timothy J Knowles
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 OQX, UK.
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2
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Caselli L, Nylander T, Malmsten M. Neutron reflectometry as a powerful tool to elucidate membrane interactions of drug delivery systems. Adv Colloid Interface Sci 2024; 325:103120. [PMID: 38428362 DOI: 10.1016/j.cis.2024.103120] [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: 11/10/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 03/03/2024]
Abstract
The last couple of decades have seen an explosion of novel colloidal drug delivery systems, which have been demonstrated to increase drug efficacy, reduce side-effects, and provide various other advantages for both small-molecule and biomacromolecular drugs. The interactions of delivery systems with biomembranes are increasingly recognized to play a key role for efficient eradication of pathogens and cancer cells, as well as for intracellular delivery of protein and nucleic acid drugs. In parallel, there has been a broadening of methodologies for investigating such systems. For example, advanced microscopy, mass-spectroscopic "omic"-techniques, as well as small-angle X-ray and neutron scattering techniques, which only a few years ago were largely restricted to rather specialized areas within basic research, are currently seeing increased interest from researchers within wide application fields. In the present discussion, focus is placed on the use of neutron reflectometry to investigate membrane interactions of colloidal drug delivery systems. Although the technique is still less extensively employed for investigations of drug delivery systems than, e.g., X-ray scattering, such studies may provide key mechanistic information regarding membrane binding, re-modelling, translocation, and permeation, of key importance for efficacy and toxicity of antimicrobial, cancer, and other therapeutics. In the following, examples of this are discussed and gaps/opportunities in the research field identified.
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Affiliation(s)
| | - Tommy Nylander
- Physical Chemistry 1, Lund University, S-221 00 Lund, Sweden
| | - Martin Malmsten
- Physical Chemistry 1, Lund University, S-221 00 Lund, Sweden; Department of Pharmacy, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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3
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Bange L, Mukhina T, Fragneto G, Rondelli V, Schneck E. Influence of adhesion-promoting glycolipids on the structure and stability of solid-supported lipid double-bilayers. SOFT MATTER 2024; 20:2113-2125. [PMID: 38349522 DOI: 10.1039/d3sm01615c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Glycolipids have a considerable influence on the interaction between adjacent biomembranes and can promote membrane adhesion trough favorable sugar-sugar "bonds" even at low glycolipid fractions. Here, in order to obtain structural insights into this phenomenon, we utilize neutron reflectometry in combination with a floating lipid bilayer architecture that brings two glycolipid-loaded lipid bilayers to close proximity. We find that selected glycolipids with di-, or oligosaccharide headgroups affect the inter-bilayer water layer thickness and appear to contribute to the stability of the double-bilayer architecture by promoting adhesion of adjacent bilayers even against induced electrostatic repulsion. However, we do not observe any redistribution of glycolipids that would maximize the density of sugar-sugar contacts. Our results point towards possible strategies for the investigation of interactions between cell surfaces involving specific protein-protein, lipid-lipid, or protein-lipid binding.
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Affiliation(s)
- Lukas Bange
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany.
| | - Tetiana Mukhina
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany.
| | - Giovanna Fragneto
- Institut Laue-Langevin, Grenoble, France
- The European Spallation Source, ERIC, Lund, Sweden
| | - Valeria Rondelli
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Italy.
| | - Emanuel Schneck
- Institute for Condensed Matter Physics, TU Darmstadt, Hochschulstraße 8, 64289 Darmstadt, Germany.
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4
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Hernández-Muñoz J, Bresme F, Tarazona P, Chacón E. Bending Modulus of Lipid Membranes from Density Correlation Functions. J Chem Theory Comput 2022; 18:3151-3163. [PMID: 35389648 PMCID: PMC9097289 DOI: 10.1021/acs.jctc.2c00099] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Indexed: 11/28/2022]
Abstract
The bending modulus κ quantifies the elasticity of biological membranes in terms of the free energy cost of increasing the membrane corrugation. Molecular dynamics (MD) simulations provide a powerful approach to quantify κ by analyzing the thermal fluctuations of the lipid bilayer. However, existing methods require the identification and filtering of non-mesoscopic fluctuation modes. State of the art methods rely on identifying a smooth surface to describe the membrane shape. These methods introduce uncertainties in calculating κ since they rely on different criteria to select the relevant fluctuation modes. Here, we present a method to compute κ using molecular simulations. Our approach circumvents the need to define a mesoscopic surface or an orientation field for the lipid tails explicitly. The bending and tilt moduli can be extracted from the analysis of the density correlation function (DCF). The method introduced here builds on the Bedeaux and Weeks (BW) theory for the DCF of fluctuating interfaces and on the coupled undulatory (CU) mode introduced by us in previous work. We test the BW-DCF method by computing the elastic properties of lipid membranes with different system sizes (from 500 to 6000 lipid molecules) and using coarse-grained (for POPC and DPPC lipids) and fully atomistic models (for DPPC). Further, we quantify the impact of cholesterol on the bending modulus of DPPC bilayers. We compare our results with bending moduli obtained with X-ray diffraction data and different computer simulation methods.
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Affiliation(s)
- Jose Hernández-Muñoz
- Departamento
de Física Teórica de la Materia Condensada, IFIMAC
Condensed Matter Physics Center, Universidad
Autónoma de Madrid, Madrid 28049, Spain
| | - Fernando Bresme
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College, W12 0BZ, London, United Kingdom
| | - Pedro Tarazona
- Departamento
de Física Teórica de la Materia Condensada, IFIMAC
Condensed Matter Physics Center, Universidad
Autónoma de Madrid, Madrid 28049, Spain
- Instituto
Nicolás Cabrera de Ciencia de Materiales, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Enrique Chacón
- Instituto
de Ciencia de Materiales de Madrid, Consejo
Superior de Investigaciones Científicas, Madrid 28049, Spain
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5
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Driven Engulfment of Janus Particles by Giant Vesicles in and out of Thermal Equilibrium. NANOMATERIALS 2022; 12:nano12091434. [PMID: 35564144 PMCID: PMC9101053 DOI: 10.3390/nano12091434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 02/01/2023]
Abstract
The interaction between Janus colloids and giant lipid vesicles was experimentally investigated to elucidate the dynamics and mechanisms related to microparticle engulfment by lipid vesicles. Janus (Pt–SiO2 and Pt–MF, where MF is melamine formaldehyde) colloids do not spontaneously adhere to POPC or DOPC bilayers, but by applying external forces via centrifugation we were able to force the contact between the particles and the membranes, which may result in a partial engulfment state of the particle. Surface properties of the Janus colloids play a crucial role in the driven particle engulfment by vesicles. Engulfment of the silica and platinum regions of the Janus particles can be observed, whereas the polymer (MF) region does not show any affinity towards the lipid bilayer. By using fluorescence microscopy, we were able to monitor the particle orientation and measure the rotational dynamics of a single Janus particle engulfed by a vesicle. By adding hydrogen peroxide to the solution, particle self-propulsion was used to perform an active transport of a giant vesicle by a single active particle. Finally, we observe that partially engulfed particles experience a membrane curvature-induced force, which pushes the colloids towards the bottom where the membrane curvature is the lowest.
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6
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John LH, Preston GM, Sansom MSP, Clifton LA. Large scale model lipid membrane movement induced by a cation switch. J Colloid Interface Sci 2021; 596:297-311. [PMID: 33839355 PMCID: PMC8109235 DOI: 10.1016/j.jcis.2021.03.078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/11/2021] [Accepted: 03/13/2021] [Indexed: 11/25/2022]
Abstract
A biomembrane sample system where millimolar changes of cations induce reversible large scale (≥ 200 Å) changes in the membrane-to-surface distance is described. The system composes of a free-floating bilayer, formed adjacent to a self-assembled monolayer (SAM). To examine the membrane movements, differently charged floating bilayers in the presence and absence of Ca2+ and Na+, respectively, were examined using neutron reflectivity and quartz crystal microbalance measurements, alongside molecular dynamics simulations. In neutron reflectivity the variation of Ca2+ and Na+ concentration enabled precision manipulation of the membrane-to-surface distance. Simulations suggest that Ca2+ ions bridge between SAM and bilayer whereas the more diffuse binding of Na+, especially to bilayers, is unable to fully overcome the repulsion between anionic floating bilayer and anionic SAM. Reproduced neutron reflectivity results with quartz crystal microbalance demonstrate the potential of this easily producible sample system to become a standard analysis tool for e.g. investigating membrane binding effects, endocytosis and cell signaling.
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Affiliation(s)
- Laura H John
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 OQX, UK
| | - Gail M Preston
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 OQX, UK.
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7
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Mukhina T, Gerelli Y, Hemmerle A, Koutsioubas A, Kovalev K, Teulon JM, Pellequer JL, Daillant J, Charitat T, Fragneto G. Insertion and activation of functional Bacteriorhodopsin in a floating bilayer. J Colloid Interface Sci 2021; 597:370-382. [PMID: 33894545 DOI: 10.1016/j.jcis.2021.03.155] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 10/21/2022]
Abstract
The proton pump transmembrane protein bacteriorhodopsin was successfully incorporated into planar floating lipid bilayers in gel and fluid phases, by applying a detergent-mediated incorporation method. The method was optimized on single supported bilayers by using quartz crystal microbalance, atomic force and fluorescence microscopy techniques. Neutron and X-ray reflectometry were used on both single and floating bilayers with the aim of determining the structure and composition of this membrane-protein system before and after protein reconstitution at sub-nanometer resolution. Lipid bilayer integrity and protein activity were preserved upon the reconstitution process. Reversible structural modifications of the membrane, induced by the bacteriorhodopsin functional activity triggered by visible light, were observed and characterized at the nanoscale.
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Affiliation(s)
- Tetiana Mukhina
- Institut Laue-Langevin, 71 av.des Martyrs, BP 156, 38042 Grenoble Cedex, France; Institut Charles Sadron, Université de Strasbourg, CNRS, UPR 22, 67034 Strasbourg, France
| | - Yuri Gerelli
- Institut Laue-Langevin, 71 av.des Martyrs, BP 156, 38042 Grenoble Cedex, France; Marche Polytechnic University, Department of Life and Environmental Sciences, Via Brecce Bianche, 60131 Ancona, Italy
| | - Arnaud Hemmerle
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - Alexandros Koutsioubas
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Kirill Kovalev
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), F-38000 Grenoble, France; Institute of Biological Information Processing (IBI-7), Structural Biochemistry, Forschungszentrum Jülich, 52428, Wilhelm-Johnen-Straße, Jülich, Germany; Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstr. 1, 85748 Garching, Germany; Jülich Centre for Structural Biology, Forschungszentrum Jülich, 52428, Wilhelm-Johnen-Straße, Jülich, Germany; Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, 141071, 9 Institutskiy per., Dolgoprudny, Russia; Institute of Crystallography, RWTH Aachen University, 52066, Jägerstraße 17-19, Aachen, Germany
| | - Jean-Marie Teulon
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), F-38000 Grenoble, France
| | - Jean-Luc Pellequer
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), F-38000 Grenoble, France
| | - Jean Daillant
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - Thierry Charitat
- Institut Charles Sadron, Université de Strasbourg, CNRS, UPR 22, 67034 Strasbourg, France
| | - Giovanna Fragneto
- Institut Laue-Langevin, 71 av.des Martyrs, BP 156, 38042 Grenoble Cedex, France
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8
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Luchini A, Vitiello G. Mimicking the Mammalian Plasma Membrane: An Overview of Lipid Membrane Models for Biophysical Studies. Biomimetics (Basel) 2020; 6:biomimetics6010003. [PMID: 33396534 PMCID: PMC7838988 DOI: 10.3390/biomimetics6010003] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 12/23/2020] [Accepted: 12/28/2020] [Indexed: 02/07/2023] Open
Abstract
Cell membranes are very complex biological systems including a large variety of lipids and proteins. Therefore, they are difficult to extract and directly investigate with biophysical methods. For many decades, the characterization of simpler biomimetic lipid membranes, which contain only a few lipid species, provided important physico-chemical information on the most abundant lipid species in cell membranes. These studies described physical and chemical properties that are most likely similar to those of real cell membranes. Indeed, biomimetic lipid membranes can be easily prepared in the lab and are compatible with multiple biophysical techniques. Lipid phase transitions, the bilayer structure, the impact of cholesterol on the structure and dynamics of lipid bilayers, and the selective recognition of target lipids by proteins, peptides, and drugs are all examples of the detailed information about cell membranes obtained by the investigation of biomimetic lipid membranes. This review focuses specifically on the advances that were achieved during the last decade in the field of biomimetic lipid membranes mimicking the mammalian plasma membrane. In particular, we provide a description of the most common types of lipid membrane models used for biophysical characterization, i.e., lipid membranes in solution and on surfaces, as well as recent examples of their applications for the investigation of protein-lipid and drug-lipid interactions. Altogether, promising directions for future developments of biomimetic lipid membranes are the further implementation of natural lipid mixtures for the development of more biologically relevant lipid membranes, as well as the development of sample preparation protocols that enable the incorporation of membrane proteins in the biomimetic lipid membranes.
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Affiliation(s)
- Alessandra Luchini
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark;
| | - Giuseppe Vitiello
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II, Piazzale Tecchio 80, 80125 Naples, Italy
- CSGI-Center for Colloid and Surface Science, via della Lastruccia 3, 50019 Sesto Fiorentino (Florence), Italy
- Correspondence:
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9
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Qian S, Sharma VK, Clifton LA. Understanding the Structure and Dynamics of Complex Biomembrane Interactions by Neutron Scattering Techniques. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15189-15211. [PMID: 33300335 DOI: 10.1021/acs.langmuir.0c02516] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The membrane is one of the key structural materials of biology at the cellular level. Composed predominantly of a bilayer of lipids with embedded and bound proteins, it defines the boundaries of the cell and many organelles essential to life and therefore is involved in almost all biological processes. Membrane-specific interactions, such as drug binding to a membrane receptor or the interactions of an antimicrobial compound with the lipid matrix of a pathogen membrane, are of interest across the scientific disciplines. Herein we present a review, aimed at nonexperts, of the major neutron scattering techniques used in membrane studies: small-angle neutron scattering, neutron membrane diffraction, neutron reflectometry, quasielastic neutron scattering, and neutron spin echo. Neutron scattering techniques are well suited to studying biological membranes. The nondestructive nature of cold neutrons means that samples can be measured for long periods without fear of beam damage from ultraviolet, electron, or X-ray radiation, and neutron beams are highly penetrating, thus offering flexibility in samples and sample environments. Most important is the strong difference in neutron scattering lengths between the two most abundant forms of hydrogen, protium and deuterium. Changing the relative amounts of protium/deuterium in a sample allows the production of a series of neutron scattering data sets, enabling the observation of differing components within complex membrane architectures. This approach can be as simple as using the naturally occurring neutron contrast between different biomolecules to study components in a complex by changing the solution H2O/D2O ratio or as complex as selectively labeling individual components with hydrogen isotopes. This review presents an overview of each experimental technique with the neutron instrument configuration, related sample preparation and sample environment, and data analysis, highlighted by a special emphasis on using prominent neutron contrast to understand structure and dynamics. This review gives researchers a practical introduction to the often enigmatic suite of neutron beamlines, thereby lowering the barrier to taking advantage of these large-facility techniques to achieve new understandings of membranes and their interactions with other molecules.
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Affiliation(s)
- Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Veerendra Kumar Sharma
- Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Luke A Clifton
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxfordshire, U.K. OX11 0QX
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10
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Benedetti F, Fu L, Thalmann F, Charitat T, Rubin A, Loison C. Coarse-Grain Simulations of Solid Supported Lipid Bilayers with Varying Hydration Levels. J Phys Chem B 2020; 124:8287-8298. [DOI: 10.1021/acs.jpcb.0c03913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Florian Benedetti
- Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622, Villeurbanne, France
| | - Li Fu
- Institut Charles Sadron, Université de Strasbourg, CNRS, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Fabrice Thalmann
- Institut Charles Sadron, Université de Strasbourg, CNRS, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Thierry Charitat
- Institut Charles Sadron, Université de Strasbourg, CNRS, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Anne Rubin
- Institut Charles Sadron, Université de Strasbourg, CNRS, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Claire Loison
- Institut Lumière Matière, University of Lyon, Université Claude Bernard Lyon 1, CNRS, F-69622, Villeurbanne, France
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11
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Abstract
Over the last 10 years, neutron reflectometry (NR) has emerged as a powerful technique for the investigation of biologically relevant thin films. The great advantage of NR with respect to many other surface-sensitive techniques is its sub-nanometer resolution that enables structural characterizations at the molecular level. In the case of bio-relevant samples, NR is non-destructive and can be used to probe thin films at buried interfaces or enclosed in bulky sample environment equipment. Moreover, recent advances in biomolecular deutera-tion enabled new labeling strategies to highlight certain structural features and to resolve with better accuracy the location of chemically similar molecules within a thin film.
In this chapter I will describe some applications of NR to bio-relevant samples and discuss some of the data analysis approaches available for biological thin films. In particular, examples on the structural characterization of biomembranes, protein films and protein-lipid interactions will be described.
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12
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Membrane interactions in drug delivery: Model cell membranes and orthogonal techniques. Adv Colloid Interface Sci 2020; 281:102177. [PMID: 32417568 DOI: 10.1016/j.cis.2020.102177] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 03/05/2020] [Accepted: 05/07/2020] [Indexed: 01/22/2023]
Abstract
To generate the desired effect in the human body, the active pharmaceutical ingredient usually needs to interact with a receptor located on the cell membrane or inside the cell. Thus, understanding membrane interactions is of great importance when it comes to the development and testing of new drug molecules or new drug delivery systems. Nowadays, there is a tremendous selection of both model cell membranes and of techniques that can be used to characterize interactions between selected model cell membranes and a drug molecule, an excipient, or a drug delivery system. Having such a wide selection of model cell membranes and techniques available makes it sometimes challenging to select the optimal combination for a specific study. Furthermore, it is difficult to compare results obtained using different model cell membranes and techniques, and not all in vitro studies translate as well to an estimation of the in vivo biological activity or understanding of mode of action. This review provides an overview of the available lipid bilayer-based model cell membranes and of the most widely employed techniques for studying membrane interactions. Finally, the need for employing complimentary characterization techniques in order to acquire more reliable and in-depth information is highlighted.
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13
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Clifton LA, Campbell RA, Sebastiani F, Campos-Terán J, Gonzalez-Martinez JF, Björklund S, Sotres J, Cárdenas M. Design and use of model membranes to study biomolecular interactions using complementary surface-sensitive techniques. Adv Colloid Interface Sci 2020; 277:102118. [PMID: 32044469 DOI: 10.1016/j.cis.2020.102118] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/24/2020] [Accepted: 01/29/2020] [Indexed: 01/07/2023]
Abstract
Cellular membranes are complex structures and simplified analogues in the form of model membranes or biomembranes are used as platforms to understand fundamental properties of the membrane itself as well as interactions with various biomolecules such as drugs, peptides and proteins. Model membranes at the air-liquid and solid-liquid interfaces can be studied using a range of complementary surface-sensitive techniques to give a detailed picture of both the structure and physicochemical properties of the membrane and its resulting interactions. In this review, we will present the main planar model membranes used in the field to date with a focus on monolayers at the air-liquid interface, supported lipid bilayers at the solid-liquid interface and advanced membrane models such as tethered and floating membranes. We will then briefly present the principles as well as the main type of information on molecular interactions at model membranes accessible using a Langmuir trough, quartz crystal microbalance with dissipation monitoring, ellipsometry, atomic force microscopy, Brewster angle microscopy, Infrared spectroscopy, and neutron and X-ray reflectometry. A consistent example for following biomolecular interactions at model membranes is used across many of the techniques in terms of the well-studied antimicrobial peptide Melittin. The overall objective is to establish an understanding of the information accessible from each technique, their respective advantages and limitations, and their complementarity.
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Affiliation(s)
- Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 OQX, United Kingdom
| | - Richard A Campbell
- Division of Pharmacy and Optometry, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Federica Sebastiani
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - José Campos-Terán
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, Av. Vasco de Quiroga 4871, Col. Santa Fe, Delegación Cuajimalpa de Morelos, 05348, Mexico; Lund Institute of advanced Neutron and X-ray Science, Lund University, Scheelevägen 19, 223 70 Lund, Sweden
| | - Juan F Gonzalez-Martinez
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Sebastian Björklund
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Javier Sotres
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden
| | - Marité Cárdenas
- Department of Biomedical Science and Biofilms - Research Center for Biointerfaces, Malmö University, 20506 Malmö, Sweden.
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14
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Su Z, Juhaniewicz-Debinska J, Sek S, Lipkowski J. Water Structure in the Submembrane Region of a Floating Lipid Bilayer: The Effect of an Ion Channel Formation and the Channel Blocker. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:409-418. [PMID: 31815479 DOI: 10.1021/acs.langmuir.9b03271] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The structure of water in the submembrane region of the bilayer of DPhPC floating (fBLM) on a monolayer of 1-thio-β-d-glucose (β-Tg)-modified gold nanoparticle film was studied by the surface-enhanced infrared absorption spectroscopy (SEIRAS). SEIRAS employs surface enhancement of the mean square electric field of the photon, which is acting on a few molecular layers above the film of gold nanoparticles. Therefore, it is uniquely suited to probe water molecules in the submembrane region and provides unique information concerning the structure of the hydrogen bond network of water surrounding the lipid bilayer. The IR spectra indicated that water with a strong hydrogen network is separating the membrane from the gold surface. This water is more ordered than the water in the bulk. When alamethicin, a peptide forming ion channels, is inserted into the membrane, the network is only slightly loosened. The addition of amiloride, an ion channel blocker, results in a significant decrease in the amount of water in the submembrane region. The remaining water has a significantly distorted hydrogen bond network. This study provides unique information about the effect of the ion channel on water transport across the bilayer. The electrode potential has a relatively small effect on water structure in the submembrane region. However, the IR studies demonstrated that water is less ordered at positive transmembrane potentials. The present results provide significant insight into the nature of hydration of a floating lipid bilayer on the gold electrode surface.
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Affiliation(s)
- ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Joanna Juhaniewicz-Debinska
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Slawomir Sek
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
- Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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15
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Clifton LA, Paracini N, Hughes AV, Lakey JH, Steinke NJ, Cooper JFK, Gavutis M, Skoda MWA. Self-Assembled Fluid Phase Floating Membranes with Tunable Water Interlayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:13735-13744. [PMID: 31553881 DOI: 10.1021/acs.langmuir.9b02350] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We present a reliable method for the fabrication of fluid phase, unsaturated lipid bilayers by self-assembly onto charged Self-Assembled Monolayer (SAM) surfaces with tunable membrane to surface aqueous interlayers. Initially, the formation of water interlayers between membranes and charged surfaces was characterized using a comparative series of bilayers deposited onto charged, self-assembled monolayers by sequential layer deposition. Using neutron reflectometry, a bilayer to surface water interlayer of ∼8 Å was found between the zwitterionic phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) membrane and an anionic carboxyl terminated grafted SAM with the formation of this layer attributed to bilayer repulsion by hydration water on the SAM surface. Furthermore, we found we could significantly reduce the technical complexity of sample fabrication through self-assembly of planar membranes onto the SAM coated surfaces. Vesicle fusion onto carboxyl-terminated monolayers yielded high coverage (>95%) bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) which floated on a 7-11 Å solution interlayer between the membrane and the surface. The surface to membrane distance was then tuned via the addition of 200 mM NaCl to the bulk solution immersing a POPC floating membrane, which caused the water interlayer to swell reversibly to ∼33 Å. This study reveals that biomimetic membrane models can be readily self-assembled from solution onto functionalized surfaces without the use of polymer supports or tethers. Once assembled, surface to membrane distance can be tailored to the experimental requirements using physiological concentrations of electrolytes. These planar bilayers only very weakly interact with the substrate and are ideally suited for use as biomimetic models for accurate in vitro biochemical and biophysical studies, as well as for technological applications, such as biosensors.
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Affiliation(s)
- Luke A Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council , Rutherford Appleton Laboratory, Harwell Science and Innovation Campus , Didcot , Oxfordshire OX11 OQX , U.K
| | - Nicoló Paracini
- Institute for Cell and Molecular Biosciences , Newcastle University , Framlington Place , Newcastle upon Tyne , NE2 4HH , United Kingdom
| | - Arwel V Hughes
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council , Rutherford Appleton Laboratory, Harwell Science and Innovation Campus , Didcot , Oxfordshire OX11 OQX , U.K
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences , Newcastle University , Framlington Place , Newcastle upon Tyne , NE2 4HH , United Kingdom
| | - Nina-Juliane Steinke
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council , Rutherford Appleton Laboratory, Harwell Science and Innovation Campus , Didcot , Oxfordshire OX11 OQX , U.K
| | - Joshaniel F K Cooper
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council , Rutherford Appleton Laboratory, Harwell Science and Innovation Campus , Didcot , Oxfordshire OX11 OQX , U.K
| | - Martynas Gavutis
- Department of Nanoengineering , Center for Physical Sciences and Technology , Savanoriu ave 231 , LT-02300 Vilnius , Lithuania
| | - Maximilian W A Skoda
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council , Rutherford Appleton Laboratory, Harwell Science and Innovation Campus , Didcot , Oxfordshire OX11 OQX , U.K
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16
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Lolicato F, Joly L, Martinez-Seara H, Fragneto G, Scoppola E, Baldelli Bombelli F, Vattulainen I, Akola J, Maccarini M. The Role of Temperature and Lipid Charge on Intake/Uptake of Cationic Gold Nanoparticles into Lipid Bilayers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1805046. [PMID: 31012268 DOI: 10.1002/smll.201805046] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 03/13/2019] [Indexed: 05/23/2023]
Abstract
Understanding the molecular mechanisms governing nanoparticle-membrane interactions is of prime importance for drug delivery and biomedical applications. Neutron reflectometry (NR) experiments are combined with atomistic and coarse-grained molecular dynamics (MD) simulations to study the interaction between cationic gold nanoparticles (AuNPs) and model lipid membranes composed of a mixture of zwitterionic di-stearoyl-phosphatidylcholine (DSPC) and anionic di-stearoyl-phosphatidylglycerol (DSPG). MD simulations show that the interaction between AuNPs and a pure DSPC lipid bilayer is modulated by a free energy barrier. This can be overcome by increasing temperature, which promotes an irreversible AuNP incorporation into the lipid bilayer. NR experiments confirm the encapsulation of the AuNPs within the lipid bilayer at temperatures around 55 °C. In contrast, the AuNP adsorption is weak and impaired by heating for a DSPC-DSPG (3:1) lipid bilayer. These results demonstrate that both the lipid charge and the temperature play pivotal roles in AuNP-membrane interactions. Furthermore, NR experiments indicate that the (negative) DSPG lipids are associated with lipid extraction upon AuNP adsorption, which is confirmed by coarse-grained MD simulations as a lipid-crawling effect driving further AuNP aggregation. Overall, the obtained detailed molecular view of the interaction mechanisms sheds light on AuNP incorporation and membrane destabilization.
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Affiliation(s)
- Fabio Lolicato
- Computational Physics Laboratory, Tampere University, P.O. Box 692, FI-33014, Tampere, Finland
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014, Helsinki, Finland
| | - Loic Joly
- Laboratory of Supramolecular and BioNano Materials, Department of Chemistry, Materials and Chemical Engineering, Politecnico di Milano, via Mancinelli 7, 20131, Milano, Italy
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042, Grenoble, France
| | - Hector Martinez-Seara
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám. 2, 16610, Prague 6, Czech Republic
| | - Giovanna Fragneto
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042, Grenoble, France
| | - Ernesto Scoppola
- Max Planck Institute of Colloids and Interfaces, 14476, Potsdam, Germany
| | - Francesca Baldelli Bombelli
- Laboratory of Supramolecular and BioNano Materials, Department of Chemistry, Materials and Chemical Engineering, Politecnico di Milano, via Mancinelli 7, 20131, Milano, Italy
| | - Ilpo Vattulainen
- Computational Physics Laboratory, Tampere University, P.O. Box 692, FI-33014, Tampere, Finland
- Department of Physics, University of Helsinki, P.O. Box 64, FI-00014, Helsinki, Finland
- MEMPHYS-Center for Biomembrane Physics
| | - Jaakko Akola
- Department of Physics, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway
| | - Marco Maccarini
- Laboratoire TIMC-IMAG, Université Grenoble Alpes, Domaine de la Merci, 38706, La Tronche Cedex, France
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17
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Clifton LA, Hall SCL, Mahmoudi N, Knowles TJ, Heinrich F, Lakey JH. Structural Investigations of Protein-Lipid Complexes Using Neutron Scattering. Methods Mol Biol 2019; 2003:201-251. [PMID: 31218621 DOI: 10.1007/978-1-4939-9512-7_11] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Neutron scattering has significant benefits for examining the structure of protein-lipid complexes. Cold (slow) neutrons are nondamaging and predominantly interact with the atomic nucleus, meaning that neutron beams can penetrate deeply into samples, which allows for flexibility in the design of samples studied. Most importantly, there is a strong difference in neutron scattering length (i.e., scattering power) between protium ([Formula: see text], 99.98% natural abundance) and deuterium ([Formula: see text] or D, 0.015%). Through the mixing of H2O and D2O in the samples and in some cases the deuterium labeling of the biomolecules, components within a complex can be hidden or enhanced in the scattering signal. This enables both the overall structure and the relative distribution of components within a complex to be resolved. Lipid-protein complexes are most commonly studied using neutron reflectometry (NR) and small angle neutron scattering (SANS). In this review the methodologies to produce and examine a variety of model biological membrane systems using SANS and NR are detailed. These systems include supported lipid bilayers derived from vesicle dispersions or Langmuir-Blodgett deposition, tethered bilayer systems, membrane protein-lipid complexes and polymer wrapped lipid nanodiscs. The three key stages of any SANS/NR study on model membrane systems-sample preparation, data collection, and analysis-are described together with some background on the techniques themselves.
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Affiliation(s)
- Luke A Clifton
- Rutherford Appleton Laboratory, Science and Technology Facilities Council, Didcot, Oxfordshire, UK.
| | - Stephen C L Hall
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Najet Mahmoudi
- Rutherford Appleton Laboratory, Science and Technology Facilities Council, Didcot, Oxfordshire, UK
| | - Timothy J Knowles
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Frank Heinrich
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
- National Institute of Standards and Technology Centre for Neutron Research, Gaithersburg, MD, USA
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne, UK.
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18
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Toledo-Fuentes X, Molinaro C, Cecchet F. Interfacial charges drive the organization of supported lipid membranes and their interaction with nanoparticles. Colloids Surf B Biointerfaces 2018; 172:254-261. [DOI: 10.1016/j.colsurfb.2018.08.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 08/10/2018] [Accepted: 08/11/2018] [Indexed: 12/27/2022]
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19
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Fragneto G, Delhom R, Joly L, Scoppola E. Neutrons and model membranes: Moving towards complexity. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2018.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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20
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Lee TH, Hirst DJ, Kulkarni K, Del Borgo MP, Aguilar MI. Exploring Molecular-Biomembrane Interactions with Surface Plasmon Resonance and Dual Polarization Interferometry Technology: Expanding the Spotlight onto Biomembrane Structure. Chem Rev 2018; 118:5392-5487. [PMID: 29793341 DOI: 10.1021/acs.chemrev.7b00729] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The molecular analysis of biomolecular-membrane interactions is central to understanding most cellular systems but has emerged as a complex technical challenge given the complexities of membrane structure and composition across all living cells. We present a review of the application of surface plasmon resonance and dual polarization interferometry-based biosensors to the study of biomembrane-based systems using both planar mono- or bilayers or liposomes. We first describe the optical principals and instrumentation of surface plasmon resonance, including both linear and extraordinary transmission modes and dual polarization interferometry. We then describe the wide range of model membrane systems that have been developed for deposition on the chips surfaces that include planar, polymer cushioned, tethered bilayers, and liposomes. This is followed by a description of the different chemical immobilization or physisorption techniques. The application of this broad range of engineered membrane surfaces to biomolecular-membrane interactions is then overviewed and how the information obtained using these techniques enhance our molecular understanding of membrane-mediated peptide and protein function. We first discuss experiments where SPR alone has been used to characterize membrane binding and describe how these studies yielded novel insight into the molecular events associated with membrane interactions and how they provided a significant impetus to more recent studies that focus on coincident membrane structure changes during binding of peptides and proteins. We then discuss the emerging limitations of not monitoring the effects on membrane structure and how SPR data can be combined with DPI to provide significant new information on how a membrane responds to the binding of peptides and proteins.
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Affiliation(s)
- Tzong-Hsien Lee
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Daniel J Hirst
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Ketav Kulkarni
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Mark P Del Borgo
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
| | - Marie-Isabel Aguilar
- Department of Biochemistry and Molecular Biology and Biomedicine Discovery Institute , Monash University , Clayton , VIC 3800 , Australia
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21
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Rosilio V. How Can Artificial Lipid Models Mimic the Complexity of Molecule–Membrane Interactions? ACTA ACUST UNITED AC 2018. [DOI: 10.1016/bs.abl.2017.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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22
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Siontorou CG, Nikoleli GP, Nikolelis DP, Karapetis SK. Artificial Lipid Membranes: Past, Present, and Future. MEMBRANES 2017; 7:E38. [PMID: 28933723 PMCID: PMC5618123 DOI: 10.3390/membranes7030038] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/05/2017] [Accepted: 07/20/2017] [Indexed: 11/17/2022]
Abstract
The multifaceted role of biological membranes prompted early the development of artificial lipid-based models with a primary view of reconstituting the natural functions in vitro so as to study and exploit chemoreception for sensor engineering. Over the years, a fair amount of knowledge on the artificial lipid membranes, as both, suspended or supported lipid films and liposomes, has been disseminated and has helped to diversify and expand initial scopes. Artificial lipid membranes can be constructed by several methods, stabilized by various means, functionalized in a variety of ways, experimented upon intensively, and broadly utilized in sensor development, drug testing, drug discovery or as molecular tools and research probes for elucidating the mechanics and the mechanisms of biological membranes. This paper reviews the state-of-the-art, discusses the diversity of applications, and presents future perspectives. The newly-introduced field of artificial cells further broadens the applicability of artificial membranes in studying the evolution of life.
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Affiliation(s)
- Christina G Siontorou
- Laboratory of Simulation of Industrial Processes, Department of Industrial Management and Technology, School of Maritime and Industry, University of Piraeus, 18534 Piraeus, Greece.
| | - Georgia-Paraskevi Nikoleli
- Laboratory of Inorganic & Analytical Chemistry, School of Chemical Engineering, Department of Chemical Sciences, National Technical University of Athens, 15780 Athens, Greece.
| | - Dimitrios P Nikolelis
- Laboratory of Environmental Chemistry, Department of Chemistry, University of Athens, 15771 Athens, Greece.
| | - Stefanos K Karapetis
- Laboratory of Inorganic & Analytical Chemistry, School of Chemical Engineering, Department of Chemical Sciences, National Technical University of Athens, 15780 Athens, Greece.
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23
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Blachon F, Harb F, Munteanu B, Piednoir A, Fulcrand R, Charitat T, Fragneto G, Pierre-Louis O, Tinland B, Rieu JP. Nanoroughness Strongly Impacts Lipid Mobility in Supported Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:2444-2453. [PMID: 28219008 DOI: 10.1021/acs.langmuir.6b03276] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In vivo lipid membranes interact with rough supramolecular structures such as protein clusters and fibrils. How these features whose size ranges from a few nanometers to a few tens of nanometers impact lipid and protein mobility is still being investigated. Here, we study supported phospholipid bilayers, a unique biomimetic model, deposited on etched surfaces bearing nanometric corrugations. The surface roughness and mean curvature are carefully characterized by AFM imaging using ultrasharp tips. Neutron specular reflectivity supplements this surface characterization and indicates that the bilayers follow the large-scale corrugations of the substrate. We measure the lateral mobility of lipids in both the fluid and gel phases by fluorescence recovery after patterned photobleaching. Although the mobility is independent of the roughness in the gel phase, it exhibits a 5-fold decrease in the fluid phase when the roughness increases from 0.2 to 10 nm. These results are interpreted with a two-phase model allowing for a strong decrease in the lipid mobility in highly curved or defect-induced gel-like nanoscale regions. This suggests a strong link between membrane curvature and fluidity, which is a key property for various cell functions such as signaling and adhesion.
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Affiliation(s)
- Florence Blachon
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Frédéric Harb
- Doctoral School for Science and Technology, Platform for Research in NanoSciences and Nanotechnology, Campus Pierre Gemayel, Lebanese University , Fanar-Metn BP 90239 Beirut, Lebanon
| | - Bogdan Munteanu
- CNRS, INSA de Lyon, LaMCoS, UMR5259, Université de Lyon , 69621 Lyon, France
| | - Agnès Piednoir
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Rémy Fulcrand
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Thierry Charitat
- Université de Strasbourg, Institut Charles Sadron , UPR22, CNRS, 67034 Strasbourg Cedex 2, France
| | - Giovanna Fragneto
- Institut Laue-Langevin , 71 Avenue des Martyrs, F-38042 Grenoble, France
| | - Olivier Pierre-Louis
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
| | - Bernard Tinland
- CINaM-CNRS, Aix-Marseille Université , UMR7325, 13288 Marseille, France
| | - Jean-Paul Rieu
- Université Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
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24
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Gumí-Audenis B, Costa L, Carlá F, Comin F, Sanz F, Giannotti MI. Structure and Nanomechanics of Model Membranes by Atomic Force Microscopy and Spectroscopy: Insights into the Role of Cholesterol and Sphingolipids. MEMBRANES 2016; 6:E58. [PMID: 27999368 PMCID: PMC5192414 DOI: 10.3390/membranes6040058] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 12/12/2016] [Accepted: 12/14/2016] [Indexed: 11/17/2022]
Abstract
Biological membranes mediate several biological processes that are directly associated with their physical properties but sometimes difficult to evaluate. Supported lipid bilayers (SLBs) are model systems widely used to characterize the structure of biological membranes. Cholesterol (Chol) plays an essential role in the modulation of membrane physical properties. It directly influences the order and mechanical stability of the lipid bilayers, and it is known to laterally segregate in rafts in the outer leaflet of the membrane together with sphingolipids (SLs). Atomic force microscope (AFM) is a powerful tool as it is capable to sense and apply forces with high accuracy, with distance and force resolution at the nanoscale, and in a controlled environment. AFM-based force spectroscopy (AFM-FS) has become a crucial technique to study the nanomechanical stability of SLBs by controlling the liquid media and the temperature variations. In this contribution, we review recent AFM and AFM-FS studies on the effect of Chol on the morphology and mechanical properties of model SLBs, including complex bilayers containing SLs. We also introduce a promising combination of AFM and X-ray (XR) techniques that allows for in situ characterization of dynamic processes, providing structural, morphological, and nanomechanical information.
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Affiliation(s)
- Berta Gumí-Audenis
- Nanoprobes and Nanoswitches group, Institute for Bioengineering of Catalunya (IBEC), Barcelona 08028, Spain.
- Physical Chemistry Department, Universitat de Barcelona, Barcelona 08028, Spain.
- European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France.
- Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid 28028, Spain.
| | - Luca Costa
- Structure and Dynamics of Nucleoproteic and Membrane Assemblies, Centre de Biochimie Structurale (CBS), Montpellier 34090, France.
| | - Francesco Carlá
- European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France.
| | - Fabio Comin
- European Synchrotron Radiation Facility (ESRF), Grenoble 38043, France.
| | - Fausto Sanz
- Nanoprobes and Nanoswitches group, Institute for Bioengineering of Catalunya (IBEC), Barcelona 08028, Spain.
- Physical Chemistry Department, Universitat de Barcelona, Barcelona 08028, Spain.
- Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid 28028, Spain.
| | - Marina I Giannotti
- Nanoprobes and Nanoswitches group, Institute for Bioengineering of Catalunya (IBEC), Barcelona 08028, Spain.
- Physical Chemistry Department, Universitat de Barcelona, Barcelona 08028, Spain.
- Networking Biomedical Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid 28028, Spain.
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25
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Hughes AV, Ciesielski F, Kalli AC, Clifton LA, Charlton TR, Sansom MSP, Webster JRP. On the interpretation of reflectivity data from lipid bilayers in terms of molecular-dynamics models. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:1227-1240. [PMID: 27917824 DOI: 10.1107/s2059798316016235] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/12/2016] [Indexed: 02/08/2023]
Abstract
Neutron and X-ray reflectivity of model membranes is increasingly used as a tool for the study of membrane structures and dynamics. As the systems under study become more complex, and as long, all-atom molecular-dynamics (MD) simulations of membranes become more available, there is increasing interest in the use of MD simulations in the analysis of reflectometry data from membranes. In order to perform this, it is necessary to produce a model of the complete interface, including not only the MD-derived structure of the membrane, but also the supporting substrate and any other interfacial layers that may be present. Here, it is shown that this is best performed by first producing a model of the occupied volume across the entire interface, and then converting this into a scattering length density (SLD) profile, rather than by splicing together the separate SLD profiles from the substrate layers and the membrane, since the latter approach can lead to discontinuities in the SLD profile and subsequent artefacts in the reflectivity calculation. It is also shown how the MD-derived membrane structure should be corrected to account for lower than optimal coverage and out-of-plane membrane fluctuations. Finally, the method of including the entire membrane structure in the reflectivity calculation is compared with an alternative approach in which the membrane components are approximated by functional forms, with only the component volumes being extracted from the simulation. It is shown that using only the fragment volumes is insufficient for a typical neutron data set of a single deuteration measured at several water contrasts, and that either weighting the model by including more structural information from the fit, or a larger data set involving a range of deuterations, are required to satisfactorily define the problem.
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Affiliation(s)
- Arwel V Hughes
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell OX11 0QX, England
| | - Fillip Ciesielski
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell OX11 0QX, England
| | - Antreas C Kalli
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, England
| | - Luke A Clifton
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell OX11 0QX, England
| | - Timothy R Charlton
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell OX11 0QX, England
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, England
| | - John R P Webster
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell OX11 0QX, England
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26
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Bunker A, Magarkar A, Viitala T. Rational design of liposomal drug delivery systems, a review: Combined experimental and computational studies of lipid membranes, liposomes and their PEGylation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2334-2352. [DOI: 10.1016/j.bbamem.2016.02.025] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 01/22/2023]
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27
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Matyszewska D, Bilewicz R, Su Z, Abbasi F, Leitch JJ, Lipkowski J. PM-IRRAS Studies of DMPC Bilayers Supported on Au(111) Electrodes Modified with Hydrophilic Monolayers of Thioglucose. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:1791-1798. [PMID: 26829620 DOI: 10.1021/acs.langmuir.5b04052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A phospholipid bilayer composed of 1,2-dimyristoyl-d54-sn-glycero-3-phosphocholine (d54-DMPC) was deposited onto the Au(111) electrode modified with a self-assembled monolayer of 1-thio-β-d-glucose (β-Tg) via the Langmuir-Blodgett and Langmuir-Schaefer (LB-LS) techniques. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) measurements were used to characterize structural and orientational changes in this model biological membrane on a hydrophilic surface modified gold electrode. The results of the spectroscopic measurements showed that the tilt angle of acyl chains obtained for deuterated DMPC bilayers supported on the β-Tg-modified gold is significantly lower than that reported previously for DMPC bilayers deposited directly on Au(111) electrodes. Moreover, tilt angles of ∼18° were obtained for d54-DMPC bilayers on β-Tg self-assembled monolayers (SAMs) at positive potentials, which are similar to the values calculated for h-DMPC deposited on bare gold in the desorbed state and to those observed for a stack of hydrated DMPC bilayers. This data confirms that the β-thioglucose SAM promotes the formation of a water cushion that separates the phospholipid bilayer from the metal surface. As a result, the DMPC polar heads are not in direct contact with the electrode and can adopt a zigzag configuration, which strengthens the chain-chain interactions and allows for an overall decrease in the tilt of the acyl chains. These novel supported model membranes may be especially useful in studies pertaining to the incorporation of peptides and proteins into phospholipid bilayers.
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Affiliation(s)
- Dorota Matyszewska
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw , Żwirki i Wigury 101, 02089 Warsaw, Poland
| | - Renata Bilewicz
- Faculty of Chemistry, University of Warsaw , ul. Pasteura 1, 02093 Warsaw, Poland
| | - ZhangFei Su
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - Fatemah Abbasi
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - J Jay Leitch
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - Jacek Lipkowski
- Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
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28
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Barker RD, McKinley LE, Titmuss S. Neutron Reflectivity as a Tool for Physics-Based Studies of Model Bacterial Membranes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 915:261-82. [PMID: 27193548 DOI: 10.1007/978-3-319-32189-9_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The principles of neutron reflectivity and its application as a tool to provide structural information at the (sub-) molecular unit length scale from models for bacterial membranes are described. The model membranes can take the form of a monolayer for a single leaflet spread at the air/water interface, or bilayers of increasing complexity at the solid/liquid interface. Solid-supported bilayers constrain the bilayer to 2D but can be used to characterize interactions with antimicrobial peptides and benchmark high throughput lab-based techniques. Floating bilayers allow for membrane fluctuations, making the phase behaviour more representative of native membranes. Bilayers of varying levels of compositional accuracy can now be constructed, facilitating studies with aims that range from characterizing the fundamental physical interactions, through to the characterization of accurate mimetics for the inner and outer membranes of Gram-negative bacteria. Studies of the interactions of antimicrobial peptides with monolayer and bilayer models for the inner and outer membranes have revealed information about the molecular control of the outer membrane permeability, and the mode of interaction of antimicrobials with both inner and outer membranes.
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Affiliation(s)
- Robert D Barker
- Institut Laue-Langevin, 71 Avenue Des Martyrs, CS 20156, 38042, Grenoble Cedex 9, France.,School of Science and Engineering, University of Dundee, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Dundee, DD1 4HN, UK
| | - Laura E McKinley
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, Scotland
| | - Simon Titmuss
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, Scotland.
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29
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Graef F, Gordon S, Lehr CM. Anti-infectives in Drug Delivery-Overcoming the Gram-Negative Bacterial Cell Envelope. Curr Top Microbiol Immunol 2016; 398:475-496. [PMID: 26942419 DOI: 10.1007/82_2016_491] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Infectious diseases are becoming a major menace to the state of health worldwide, with difficulties in effective treatment especially of nosocomial infections caused by Gram-negative bacteria being increasingly reported. Inadequate permeation of anti-infectives into or across the Gram-negative bacterial cell envelope, due to its intrinsic barrier function as well as barrier enhancement mediated by resistance mechanisms, can be identified as one of the major reasons for insufficient therapeutic effects. Several in vitro, in silico, and in cellulo models are currently employed to increase the knowledge of anti-infective transport processes into or across the bacterial cell envelope; however, all such models exhibit drawbacks or have limitations with respect to the information they are able to provide. Thus, new approaches which allow for more comprehensive characterization of anti-infective permeation processes (and as such, would be usable as screening methods in early drug discovery and development) are desperately needed. Furthermore, delivery methods or technologies capable of enhancing anti-infective permeation into or across the bacterial cell envelope are required. In this respect, particle-based carrier systems have already been shown to provide the opportunity to overcome compound-related difficulties and allow for targeted delivery. In addition, formulations combining efflux pump inhibitors or antimicrobial peptides with anti-infectives show promise in the restoration of antibiotic activity in resistant bacterial strains. Despite considerable progress in this field however, the design of carriers to specifically enhance transport across the bacterial envelope or to target difficult-to-treat (e.g., intracellular) infections remains an urgently needed area of improvement. What follows is a summary and evaluation of the state of the art of both bacterial permeation models and advanced anti-infective formulation strategies, together with an outlook for future directions in these fields.
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Affiliation(s)
- Florian Graef
- Department of Drug Delivery, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Saarbrücken, Germany
| | - Sarah Gordon
- Department of Drug Delivery, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Saarbrücken, Germany
| | - Claus-Michael Lehr
- Department of Drug Delivery, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Center for Infection Research (HZI), Saarbrücken, Germany. .,Department of Pharmacy, Saarland University, Saarbrücken, Germany.
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30
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Belička M, Gerelli Y, Kučerka N, Fragneto G. The component group structure of DPPC bilayers obtained by specular neutron reflectometry. SOFT MATTER 2015; 11:6275-6283. [PMID: 26160133 DOI: 10.1039/c5sm00274e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Specular neutron reflectometry was measured on a floating bilayer system consisting of 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine deposited over a 1,2-dibehenoyl-sn-glycero-3-phosphocholine bilayer at 25 and 55 °C. The internal structure of lipid bilayers was described by a one-dimensional neutron scattering length density profile model, originally developed for the evaluation of small-angle scattering data. The reflectivity data from the supported bilayer were evaluated separately and used further as constraints in modeling the floating bilayer reflectivity curves. The model reflectivity curves successfully describe the experimental reflectivities of the supported bilayer in the gel phase and the floating bilayer system in the liquid-crystalline phase. The results yield an internal structure of a deposited bilayer and a floating bilayer on the level of component groups of lipid molecules. The obtained structure of the floating d62-diC16:0PC bilayer displays high resemblance of the bilayer structure in the form of unilamellar vesicles. At the same time, however, the results show differences in comparison to unilamellar vesicle bilayers, most likely due to the undulations of supported bilayers.
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Affiliation(s)
- Michal Belička
- Department of Physical Chemistry of Drugs, Faculty of Pharmacy, Comenius University, Odbojárov 10, SK-832 32 Bratislava, Slovakia.
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31
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Foglia F, Lawrence M, Barlow D. Studies of model biological and bio-mimetic membrane structure: Reflectivity vs diffraction, a critical comparison. Curr Opin Colloid Interface Sci 2015. [DOI: 10.1016/j.cocis.2015.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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32
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Wang L, Roth JS, Han X, Evans SD. Photosynthetic Proteins in Supported Lipid Bilayers: Towards a Biokleptic Approach for Energy Capture. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3306-3318. [PMID: 25727786 DOI: 10.1002/smll.201403469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/11/2015] [Indexed: 06/04/2023]
Abstract
In nature, plants and some bacteria have evolved an ability to convert solar energy into chemical energy usable by the organism. This process involves several proteins and the creation of a chemical gradient across the cell membrane. To transfer this process to a laboratory environment, several conditions have to be met: i) proteins need to be reconstituted into a lipid membrane, ii) the proteins need to be correctly oriented and functional and, finally, iii) the lipid membrane should be capable of maintaining chemical and electrical gradients. Investigating the processes of photosynthesis and energy generation in vivo is a difficult task due to the complexity of the membrane and its associated proteins. Solid, supported lipid bilayers provide a good model system for the systematic investigation of the different components involved in the photosynthetic pathway. In this review, the progress made to date in the development of supported lipid bilayer systems suitable for the investigation of membrane proteins is described; in particular, there is a focus on those used for the reconstitution of proteins involved in light capture.
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Affiliation(s)
- Lei Wang
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
- State Key Laboratory of Urban Water Resource and Environment, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, 150001, China
| | - Johannes S Roth
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin, 150001, China
| | - Stephen D Evans
- School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
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33
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Hughes AV, Holt SA, Daulton E, Soliakov A, Charlton TR, Roser SJ, Lakey JH. High coverage fluid-phase floating lipid bilayers supported by ω-thiolipid self-assembled monolayers. J R Soc Interface 2015; 11:20140245. [PMID: 25030385 PMCID: PMC4233693 DOI: 10.1098/rsif.2014.0447] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Large area lipid bilayers, on solid surfaces, are useful in physical studies of biological membranes. It is advantageous to minimize the interactions of these bilayers with the substrate and this can be achieved via the formation of a floating supported bilayer (FSB) upon either a surface bound phospholipid bilayer or monolayer. The FSB's independence is enabled by the continuous water layer (greater than 15 Å) that remains between the two. However, previous FSBs have had limited stability and low density. Here, we demonstrate by surface plasmon resonance and neutron reflectivity, the formation of a complete self-assembled monolayer (SAM) on gold surfaces by a synthetic phosphatidylcholine bearing a thiol group at the end of one fatty acyl chain. Furthermore, a very dense FSB (more than 96%) of saturated phosphatidylcholine can be formed on this SAM by sequential Langmuir–Blodgett and Langmuir–Schaefer procedures. Neutron reflectivity used both isotopic and magnetic contrast to enhance the accuracy of the data fits. This system offers the means to study transmembrane proteins, membrane potential effects (using the gold as an electrode) and even model bacterial outer membranes. Using unsaturated phosphatidylcholines, which have previously failed to form stable FSBs, we achieved a coverage of 73%.
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Affiliation(s)
- Arwel V Hughes
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Harwell OX11 0QX, UK
| | - Stephen A Holt
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC 2001, New South Wales 2232, Australia
| | - Emma Daulton
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Harwell OX11 0QX, UK Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Andrei Soliakov
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Timothy R Charlton
- ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Harwell OX11 0QX, UK
| | - Steven J Roser
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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34
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Vargas JN, Seemann R, Fleury JB. Fast membrane hemifusion via dewetting between lipid bilayers. SOFT MATTER 2014; 10:9293-9299. [PMID: 25330351 DOI: 10.1039/c4sm01577k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The behavior of lipid bilayers is important to understand the functionality of cells like the trafficking of ions. Standard procedures to explore the properties of lipid bilayers and hemifused states typically use supported membranes or vesicles. Both techniques have several shortcomings in terms of bio-relevance or accessibility for measurements. In this article, the formation of individual free standing hemifused states between model cell membranes is studied using an optimized microfluidic scheme which allows for simultaneous optical and electrophysiological measurements. In the first step, two model membranes are formed at a desired location within a microfluidic device using a variation of the droplet interface bilayer (DiB) technique. In the second step, the two model membranes are brought into contact forming a single hemifused state. For all tested lipids, the hemifused state between free standing membranes forms within hundreds of milliseconds, i.e. several orders of magnitude faster than those reported in literature. The formation of a hemifused state is observed as a two stage process, whereas the second stage can be explained as a dewetting process under no-slip boundary conditions. The formed hemifusion states have a long lifetime and a single fusion event can be observed when triggered by an applied electric field as demonstrated for monoolein.
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Affiliation(s)
- Jose Nabor Vargas
- Experimental Physics, Saarland University, 66123 Saarbrücken, Germany.
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35
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Sanii B, Haxton TK, Olivier GK, Cho A, Barton B, Proulx C, Whitelam S, Zuckermann RN. Structure-determining step in the hierarchical assembly of peptoid nanosheets. ACS NANO 2014; 8:11674-11684. [PMID: 25327498 DOI: 10.1021/nn505007u] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Organic two-dimensional nanomaterials are of growing importance, yet few general synthetic methods exist to produce them in high yields and to precisely functionalize them. We previously developed an efficient hierarchical supramolecular assembly route to peptoid bilayer nanosheets, where the organization of biomimetic polymer sequences is catalyzed by an air-water interface. Here we determine at which stages of assembly the nanoscale and atomic-scale order appear. We used X-ray scattering, grazing incidence X-ray scattering at the air-water interface, electron diffraction, and a recently developed computational coarse-grained peptoid model to probe the molecular ordering at various stages of assembly. We found that lateral packing and organization of the chains occurs during the formation of a peptoid monolayer, prior to its collapse into a bilayer. Identifying the structure-determining step enables strategies to influence nanosheet order, to predict and optimize production yields, and to further engineer this class of material. More generally, our results provide a guide for using fluid interfaces to catalytically assemble 2D nanomaterials.
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Affiliation(s)
- Babak Sanii
- The Molecular Foundry, Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, California 94720, United States
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36
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Mashaghi A, Mashaghi S, Reviakine I, Heeren RMA, Sandoghdar V, Bonn M. Label-free characterization of biomembranes: from structure to dynamics. Chem Soc Rev 2014; 43:887-900. [PMID: 24253187 DOI: 10.1039/c3cs60243e] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We review recent progress in the study of the structure and dynamics of phospholipid membranes and associated proteins, using novel label-free analytical tools. We describe these techniques and illustrate them with examples highlighting current capabilities and limitations. Recent advances in applying such techniques to biological and model membranes for biophysical studies and biosensing applications are presented, and future prospects are discussed.
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Affiliation(s)
- Alireza Mashaghi
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
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37
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Hertrich S, Stetter F, Rühm A, Hugel T, Nickel B. Highly hydrated deformable polyethylene glycol-tethered lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9442-7. [PMID: 25046694 DOI: 10.1021/la4045804] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The realization of a solid-supported lipid bilayer acting as a workbench for the study of membrane processes is a difficult task. For robustness, the bilayer has to be tethered to the substrate. At the same time, diffusion of the lipids and plastic deformations of the membrane should not be obstructed. Furthermore, a highly hydrated surrounding is mandatory. Here, we show that grafting of a polyethylene glycol-lipid construct (PEG2000-DSPE) to a silicon oxide surface via multiple-step silane chemistry and subsequent deposition of lipids by spin-coating result in a cushioned membrane that has the desired properties. Neutron and X-ray reflectometry measurements are combined to access thickness, density, and hydration of the bilayer and the PEG cushion. We observe a spacer of 55 Å thickness between lipid bilayer and silicon-oxide surface with a rather high hydration of up to 90 ± 3% water. While 11.5 ± 3% of the lipids are grafted to the surface, as determined from the neutron data, the diffusion constant of the lipids, as probed by diffusion of 0.5% Texas Red labeled lipids, remains rather large (D = 2.1 ± 0.1 μm(2)/s), which is a reduction of only 12% compared to a supported lipid bilayer reference without immobilized lipids. Finally, AFM indentation confirms the plastic behavior of the membrane against deformation. We show that rupture of the bilayer does not occur before the deformation exceeds 40 Å. Altogether, the presented PEG-tethered lipid bilayer mimics the deformability of natural cell membranes much better than standard solid-supported lipid bilayers.
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Affiliation(s)
- Samira Hertrich
- Fakultät für Physik & CeNS, Ludwig-Maximilians-Universität , Geschwister-Scholl-Platz 1, 80539 Munich, Germany
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38
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Bourgaux C, Couvreur P. Interactions of anticancer drugs with biomembranes: what can we learn from model membranes? J Control Release 2014; 190:127-38. [PMID: 24859379 DOI: 10.1016/j.jconrel.2014.05.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/05/2014] [Accepted: 05/07/2014] [Indexed: 10/25/2022]
Abstract
The interactions of anticancer drugs with cell membranes are of primary importance for drug transport, accumulation and activity. However, these interactions are very difficult to investigate because of the complexity of biological membranes. Lipid model membranes have therefore been built to gain insight into the collective role of lipids in drug-membrane interactions. Membranes can act as a barrier for drug molecules, sequester them or conversely may allow them to freely diffuse, thereby modulating the accumulation of drugs into cells. Lipid membranes also affect the ability of the efflux pump Pgp to bind and efflux anticancer drugs from cells. On the other hand, anticancer drugs can alter the structure and properties of lipid membranes, which are expected to influence the functioning of embedded proteins. The relevance of lipid model membranes to assess interactions between anticancer drugs and biomembranes is evidenced.
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Affiliation(s)
- Claudie Bourgaux
- Institut Galien-Paris Sud, UMR CNRS 8612, Faculté de Pharmacie, Université Paris-Sud, 5 rue J.B. Clément, 92 296 Châtenay-Malabry Cedex, France
| | - Patrick Couvreur
- Institut Galien-Paris Sud, UMR CNRS 8612, Faculté de Pharmacie, Université Paris-Sud, 5 rue J.B. Clément, 92 296 Châtenay-Malabry Cedex, France
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Abstract
When engineering lipid membranes for applications, it is essential to characterize them to avoid artifacts introduced by manipulation and the experimental environment. Wide-angle X-ray scattering is a powerful structural characterization tool for well-ordered lipid systems. It reveals remarkable differences in rotational order parameters for samples prepared in different ways. New data and perspectives are presented here for multilamellar systems that support and extend the characterization work on unilamellar systems that is reported by Watkins et al. in this issue of ACS Nano.
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40
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Clifton LA, Skoda MWA, Daulton EL, Hughes AV, Le Brun AP, Lakey JH, Holt SA. Asymmetric phospholipid: lipopolysaccharide bilayers; a Gram-negative bacterial outer membrane mimic. J R Soc Interface 2013; 10:20130810. [PMID: 24132206 PMCID: PMC3808558 DOI: 10.1098/rsif.2013.0810] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 09/25/2013] [Indexed: 01/02/2023] Open
Abstract
The Gram-negative bacterial outer membrane (OM) is a complex and highly asymmetric biological barrier but the small size of bacteria has hindered advances in in vivo examination of membrane dynamics. Thus, model OMs, amenable to physical study, are important sources of data. Here, we present data from asymmetric bilayers which emulate the OM and are formed by a simple two-step approach. The bilayers were deposited on an SiO2 surface by Langmuir-Blodgett deposition of phosphatidylcholine as the inner leaflet and, via Langmuir-Schaefer deposition, an outer leaflet of either Lipid A or Escherichia coli rough lipopolysaccharides (LPS). The membranes were examined using neutron reflectometry (NR) to examine the coverage and mixing of lipids between the bilayer leaflets. NR data showed that in all cases, the initial deposition asymmetry was mostly maintained for more than 16 h. This stability enabled the sizes of the headgroups and bilayer roughness of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and Lipid A, Rc-LPS and Ra-LPS to be clearly resolved. The results show that rough LPS can be manipulated like phospholipids and used to fabricate advanced asymmetric bacterial membrane models using well-known bilayer deposition techniques. Such models will enable OM dynamics and interactions to be studied under in vivo-like conditions.
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Affiliation(s)
- Luke A. Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - Maximilian W. A. Skoda
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - Emma L. Daulton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
- Department of Chemistry, University of Bath, Bath BA2 7AY, UK
| | - Arwel V. Hughes
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell, Oxfordshire OX11 OQX, UK
| | - Anton P. Le Brun
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
| | - Jeremy H. Lakey
- Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
| | - Stephen A. Holt
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales 2232, Australia
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41
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Golub M, Lott D, Watkins EB, Garamus V, Luthringer B, Stoermer M, Schreyer A, Willumeit R. X-ray and neutron investigation of self-assembled lipid layers on a titanium surface. Biointerphases 2013; 8:21. [DOI: 10.1186/1559-4106-8-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 08/12/2013] [Indexed: 11/10/2022] Open
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42
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Simon A, Gounou C, Tan S, Tiefenauer L, Di Berardino M, Brisson AR. Free-standing lipid films stabilized by Annexin-A5. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2739-44. [DOI: 10.1016/j.bbamem.2013.07.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 07/16/2013] [Accepted: 07/24/2013] [Indexed: 10/26/2022]
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43
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Le Brun A, Clifton LA, Halbert CE, Lin B, Meron M, Holden PJ, Lakey JH, Holt SA. Structural characterization of a model gram-negative bacterial surface using lipopolysaccharides from rough strains of Escherichia coli. Biomacromolecules 2013; 14:2014-22. [PMID: 23617615 PMCID: PMC3679557 DOI: 10.1021/bm400356m] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/18/2013] [Indexed: 12/29/2022]
Abstract
Lipopolysaccharides (LPS) make up approximately 75% of the Gram-negative bacterial outer membrane (OM) surface, but because of the complexity of the molecule, there are very few model OMs that include LPS. The LPS molecule consists of lipid A, which anchors the LPS within the OM, a core polysaccharide region, and a variable O-antigen polysaccharide chain. In this work we used RcLPS (consisting of lipid A plus the first seven sugars of the core polysaccharide) from a rough strain of Escherichia coli to form stable monolayers of LPS at the air-liquid interface. The vertical structure RcLPS monolayers were characterized using neutron and X-ray reflectometry, while the lateral structure was investigated using grazing incidence X-ray diffraction and Brewster angle microscopy. It was found that RcLPS monolayers at surface pressures of 20 mN m(-1) and above are resolved as hydrocarbon tails, an inner headgroup, and an outer headgroup of polysaccharide with increasing solvation from tails to outer headgroups. The lateral organization of the hydrocarbon lipid chains displays an oblique hexagonal unit cell at all surface pressures, with only the chain tilt angle changing with surface pressure. This is in contrast to lipid A, which displays hexagonal or, above 20 mN m(-1), distorted hexagonal packing. This work provides the first complete structural analysis of a realistic E. coli OM surface model.
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Affiliation(s)
- Anton
P. Le Brun
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Luke A. Clifton
- ISIS Neutron Facility, STFC Rutherford
Appleton Laboratory, Didcot, Oxfordshire
OX11 0QX, United Kingdom
| | - Candice E. Halbert
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee
37831, United States
| | - Binhua Lin
- Consortium
of Advanced Radiation
Sources (CARS), University of Chicago,
Chicago, Illinois 60637, United States
| | - Mati Meron
- Consortium
of Advanced Radiation
Sources (CARS), University of Chicago,
Chicago, Illinois 60637, United States
| | - Peter J. Holden
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Jeremy H. Lakey
- Institute for Cell and Molecular
Biosciences, Newcastle University, Framlington
Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Stephen A. Holt
- Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
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44
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Tatur S, Maccarini M, Barker R, Nelson A, Fragneto G. Effect of functionalized gold nanoparticles on floating lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:6606-14. [PMID: 23638939 DOI: 10.1021/la401074y] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The development of novel nano-engineered materials poses important questions regarding the impact of these new materials on living systems. Possible adverse effects must be assessed in order to prevent risks for health and the environment. On the other hand, a thorough understanding of their interaction with biological systems might also result in the creation of novel biomedical applications. We present a study on the interaction of model lipid membranes with gold nanoparticles (AuNP) of different surface modifications. Neutron reflectometry experiments on zwitterionic lipid double bilayers were performed in the presence of AuNP functionalized with cationic and anionic head groups. Structural information was obtained that provided insight into the fate of the AuNPs with regard to the integrity of the model cell membranes. The AuNPs functionalized with cationic head groups penetrate into the hydrophobic moiety of the lipid bilayers and cause membrane disruption at an increased concentration. In contrast, the AuNPs functionalized with anionic head groups do not enter but seem to impede the destruction of the lipid bilayer at an alkaline pH. The information obtained might influence the strategy for a better nanoparticle risk assessment based on a surface charge evaluation and contribute to nano-safety considerations during their design.
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Affiliation(s)
- Sabina Tatur
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607, United States.
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45
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Robertson JWF, Kasianowicz JJ, Banerjee S. Analytical Approaches for Studying Transporters, Channels and Porins. Chem Rev 2012; 112:6227-49. [DOI: 10.1021/cr300317z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Joseph W. F. Robertson
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - John J. Kasianowicz
- Physical Measurement Laboratory,
National Institute of Standards and Technology, Gaithersburg, Maryland
20899, United States
| | - Soojay Banerjee
- National
Institute of Neurological
Disorders and Stroke, Bethesda, Maryland 20824, United States
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