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Gavutis M, Schulze-Niemand E, Lee HH, Liedberg B, Stein M, Valiokas R. Bilayer lipid membrane formation on surface assemblies with sparsely distributed tethers. NANOSCALE 2023. [PMID: 37128711 DOI: 10.1039/d2nr07069c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A combined computational and experimental study of small unilamellar vesicle (SUV) fusion on mixed self-assembled monolayers (SAMs) terminated with different deuterated tether moieties (-(CD2)7CD3 or -(CD2)15CD3) is reported. Tethered bilayer lipid membrane (tBLM) formation of synthetic 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine was initially probed on SAMs with controlled tether (d-alkyl tail) surface densities and lateral molecular packing using quartz crystal microbalance with dissipation monitoring (QCM-D). Long time-scale coarse-grained molecular dynamics (MD) simulations were then employed to elucidate the mechanisms behind the interaction between the SUVs and the different phases formed by the -(CD2)7CD3 and -(CD2)15CD3 tethers. Furthermore, a series of real time kinetics was recorded under different osmotic conditions using QCM-D to determine the accumulated lipid mass and for probing the fusion process. It is shown that the key factors driving the SUV fusion and tBLM formation on this type of surfaces involve tether insertion into the SUVs along with vesicle deformation. It is also evident that surface densities of the tethers as small as a few mol% are sufficient to obtain stable tBLMs with a high reproducibility. The described "sparsely tethered" tBLM system can be advantageous in studying different biophysical phenomena, such as membrane protein insertion, effects of receptor clustering, and raft formation.
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Affiliation(s)
- Martynas Gavutis
- Department of Nanoengineering, Center for Physical Sciences and Technology, Savanorių 231, 02300 Vilnius, Lithuania.
| | - Eric Schulze-Niemand
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical System, Magdeburg, Germany
- Institute of Experimental Internal Medicine, Medical Faculty, Otto von Guericke University, 39120 Magdeburg, Germany
| | - Hung-Hsun Lee
- Division of Molecular Physics, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
| | - Bo Liedberg
- Division of Molecular Physics, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden
| | - Matthias Stein
- Molecular Simulations and Design Group, Max Planck Institute for Dynamics of Complex Technical System, Magdeburg, Germany
| | - Ramūnas Valiokas
- Department of Nanoengineering, Center for Physical Sciences and Technology, Savanorių 231, 02300 Vilnius, Lithuania.
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2
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Cheppali SK, Dharan R, Katzenelson R, Sorkin R. Supported Natural Membranes on Microspheres for Protein-Protein Interaction Studies. ACS APPLIED MATERIALS & INTERFACES 2022; 14:49532-49541. [PMID: 36306148 DOI: 10.1021/acsami.2c13095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Multiple biological and pathological processes, such as signaling, cell-cell communication, and infection by various viruses, occur at the plasma membrane. The eukaryotic plasma membrane is made up of thousands of different lipids, membrane proteins, and glycolipids, and its composition is dynamic and constantly changing. Due to the central importance of membranes on the one hand and their complexity on the other, membrane model systems are instrumental for interrogating membrane-related biological processes. Here, we develop a new tool for protein-membrane interaction studies. Our method is based on natural membranes obtained from extracellular vesicles. We form membrane bilayers supported on polystyrene microspheres that can be trapped and manipulated using optical tweezers. This method allows working with membrane proteins of interest within a background of native membrane components where their correct orientation is preserved. We demonstrate our method's applicability by successfully measuring the interaction forces between the Spike protein of SARS-CoV-2 and its human receptor, ACE2. We further show that these interactions are blocked by the addition of an antibody against the receptor binding domain of the Spike protein. Our approach is versatile and broadly applicable for various membrane biology and biophysics questions.
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Affiliation(s)
- Sudheer K Cheppali
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Light-Matter Interaction, Tel Aviv University, Tel Aviv, Israel6997801
| | - Raviv Dharan
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Light-Matter Interaction, Tel Aviv University, Tel Aviv, Israel6997801
| | - Roni Katzenelson
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Light-Matter Interaction, Tel Aviv University, Tel Aviv, Israel6997801
| | - Raya Sorkin
- Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv, Israel6997801
- Center for Light-Matter Interaction, Tel Aviv University, Tel Aviv, Israel6997801
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3
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Nishimura T, Sasaki Y, Akiyoshi K. Thermoresponsive glycopolymer vesicles: in situ observation of morphological changes and triggered cargo release. Polym J 2021. [DOI: 10.1038/s41428-021-00488-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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4
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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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5
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Uribe J, Liu HY, Mohamed Z, Chiou AE, Fischbach C, Daniel S. Supported Membrane Platform to Assess Surface Interactions between Extracellular Vesicles and Stromal Cells. ACS Biomater Sci Eng 2020; 6:3945-3956. [PMID: 33463350 DOI: 10.1021/acsbiomaterials.0c00133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Extracellular vesicles (EVs) are membrane-encapsulated particles secreted by eukaryotic cells that stimulate cell communication and horizontal cargo exchange. EV interactions with stromal cells can result in molecular changes in the recipient cell and, in some cases, lead to disease progression. However, mechanisms leading to these changes are poorly understood. A few model systems are available for studying the outcomes of surface interactions between EV membranes with stromal cells. Here, we created a hybrid supported bilayer incorporating EVs membrane material, called an extracellular vesicle supported bilayer, EVSB. Using EVSBs, we investigated the surface interactions between breast cancer EVs and adipose-derived stem cells (ADSCs) by culturing ADSCs on EVSBs and analyzing cell adhesion, spreading, viability, vascular endothelial growth factor (VEGF) secretion, and myofibroblast differentiation. Results show that cell viability, adhesion, spreading, and proangiogenic activity were enhanced, conditions that promote oncogenic activity, but cell differentiation was not. This model system could be used to develop therapeutic strategies to limit EV-ADSC interactions and proangiogenic conditions. Finally, this model system is not limited to the study of cancer but can be used to study surface interactions between EVs from any origin and any target cell to investigate EV mechanisms leading to cellular changes in other diseases.
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Affiliation(s)
- Johana Uribe
- Meinig School of Biomedical Engineering, Cornell University, 101 Weill Hall, 273 Tower Road, Ithaca, New York 14853, United States
| | - Han-Yuan Liu
- School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, 6-44 Ho Plaza, Ithaca, New York 14853, United States
| | - Zeinab Mohamed
- Meinig School of Biomedical Engineering, Cornell University, 101 Weill Hall, 273 Tower Road, Ithaca, New York 14853, United States
| | - Aaron E Chiou
- Meinig School of Biomedical Engineering, Cornell University, 101 Weill Hall, 273 Tower Road, Ithaca, New York 14853, United States
| | - Claudia Fischbach
- Meinig School of Biomedical Engineering, Cornell University, 101 Weill Hall, 273 Tower Road, Ithaca, New York 14853, United States.,School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, 6-44 Ho Plaza, Ithaca, New York 14853, United States
| | - Susan Daniel
- Meinig School of Biomedical Engineering, Cornell University, 101 Weill Hall, 273 Tower Road, Ithaca, New York 14853, United States.,School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, 6-44 Ho Plaza, Ithaca, New York 14853, United States
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6
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Noguchi H. Detachment of a fluid membrane from a substrate and vesiculation. SOFT MATTER 2019; 15:8741-8748. [PMID: 31577325 DOI: 10.1039/c9sm01622h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The detachment dynamics of a fluid membrane with isotropic spontaneous curvature from a flat substrate are studied by using meshless membrane simulations. The membrane is detached from an open edge leading to vesicle formation. With strong adhesion, the competition between the bending and adhesion energies determines the minimum value of the spontaneous curvature for the detachment. In contrast, with weak adhesion, detachment occurs at smaller spontaneous curvatures due to the membrane thermal undulation. When parts of the membrane are pinned on the substrate, the detachment becomes slower and a remaining membrane patch forms straight or concave membrane edges. The edge undulation induces vesiculation of long strips and disk-shaped patches. Therefore, membrane rolling is obtained only for membrane strips shorter than the wavelength for deformation into unduloids. This suggests that the rolling observed for Ca2+-dependent membrane-binding proteins annexins A3, A4, A5, and A13 results from the anisotropic spontaneous curvature induced by the proteins.
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Affiliation(s)
- Hiroshi Noguchi
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan. and Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne, France
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7
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N’Diaye M, Michel JP, Rosilio V. Relevance of charges and polymer mechanical stiffness in the mechanism and kinetics of formation of liponanoparticles probed by the supported bilayer model approach. Phys Chem Chem Phys 2019; 21:4306-4319. [DOI: 10.1039/c8cp06955g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Parameters controlling the mechanism and kinetics of formation of liponanoparticles are determined using supported lipid bilayer models.
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Affiliation(s)
- Marline N’Diaye
- Institut Galien Paris-Sud
- CNRS
- Univ. Paris-Sud
- Université Paris-Saclay
- 92296 Châtenay-Malabry
| | - Jean-Philippe Michel
- Institut Galien Paris-Sud
- CNRS
- Univ. Paris-Sud
- Université Paris-Saclay
- 92296 Châtenay-Malabry
| | - Véronique Rosilio
- Institut Galien Paris-Sud
- CNRS
- Univ. Paris-Sud
- Université Paris-Saclay
- 92296 Châtenay-Malabry
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8
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Zhang G, Müller M. Rupturing the hemi-fission intermediate in membrane fission under tension: Reaction coordinates, kinetic pathways, and free-energy barriers. J Chem Phys 2018; 147:064906. [PMID: 28810752 DOI: 10.1063/1.4997575] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Membrane fission is a fundamental process in cells, involved inter alia in endocytosis, intracellular trafficking, and virus infection. Its underlying molecular mechanism, however, is only incompletely understood. Recently, experiments and computer simulation studies have revealed that dynamin-mediated membrane fission is a two-step process that proceeds via a metastable hemi-fission intermediate (or wormlike micelle) formed by dynamin's constriction. Importantly, this hemi-fission intermediate is remarkably metastable, i.e., its subsequent rupture that completes the fission process does not occur spontaneously but requires additional, external effects, e.g., dynamin's (unknown) conformational changes or membrane tension. Using simulations of a coarse-grained, implicit-solvent model of lipid membranes, we investigate the molecular mechanism of rupturing the hemi-fission intermediate, such as its pathway, the concomitant transition states, and barriers, as well as the role of membrane tension. The membrane tension is controlled by the chemical potential of the lipids, and the free-energy landscape as a function of two reaction coordinates is obtained by grand canonical Wang-Landau sampling. Our results show that, in the course of rupturing, the hemi-fission intermediate undergoes a "thinning → local pinching → rupture/fission" pathway, with a bottle-neck-shaped cylindrical micelle as a transition state. Although an increase of membrane tension facilitates the fission process by reducing the corresponding free-energy barrier, for biologically relevant tensions, the free-energy barriers still significantly exceed the thermal energy scale kBT.
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Affiliation(s)
- Guojie Zhang
- Institute for Theoretical Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Marcus Müller
- Institute for Theoretical Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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9
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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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10
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Shao J, Wen C, Xuan M, Zhang H, Frueh J, Wan M, Gao L, He Q. Polyelectrolyte multilayer-cushioned fluid lipid bilayers: a parachute model. Phys Chem Chem Phys 2018; 19:2008-2016. [PMID: 28009025 DOI: 10.1039/c6cp06787e] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Lipid bilayer membranes supported on polyelectrolyte multilayers are widely used as a new biomembrane model that connects biological and artificial materials since these ultrathin polyelectrolyte supports may mimic the role of the extracellular matrix and cell skeleton in living systems. Polyelectrolyte multilayers were fabricated by a layer-by-layer self-assembly technique. A quartz crystal microbalance with dissipation was used in real time to monitor the interaction between phospholipids and polyelectrolytes in situ on a planar substrate. The surface properties of polyelectrolyte films were investigated by the measurement of contact angles and zeta potential. Phospholipid charge, buffer pH and substrate hydrophilicity were proved to be essential for vesicle adsorption, rupture, fusion and formation of continuous lipid bilayers on the polyelectrolyte multilayers. The results clearly demonstrated that only the mixture of phosphatidylcholine and phosphatidic acid (4 : 1) resulted in fluid bilayers on chitosan and alginate multilayers with chitosan as a top layer at pH 6.5. A coarse-grained molecular simulation study elucidated that the exact mechanism of the formation of fluid lipid bilayers resembles a "parachute" model. As the closest model to the real membrane, polyelectrolyte multilayer-cushioned fluid lipid bilayers can be appropriate candidates for application in biomedical fields.
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Affiliation(s)
- Jingxin Shao
- Key Lab for Microsystems and Microstructures Manufacturing, Micro/Nanotechnology Research Centre, Harbin Institute of Technology, Harbin 150080, China.
| | - Caixia Wen
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Mingjun Xuan
- Key Lab for Microsystems and Microstructures Manufacturing, Micro/Nanotechnology Research Centre, Harbin Institute of Technology, Harbin 150080, China.
| | - Hongyue Zhang
- Key Lab for Microsystems and Microstructures Manufacturing, Micro/Nanotechnology Research Centre, Harbin Institute of Technology, Harbin 150080, China.
| | - Johannes Frueh
- Key Lab for Microsystems and Microstructures Manufacturing, Micro/Nanotechnology Research Centre, Harbin Institute of Technology, Harbin 150080, China.
| | - Mingwei Wan
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Lianghui Gao
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
| | - Qiang He
- Key Lab for Microsystems and Microstructures Manufacturing, Micro/Nanotechnology Research Centre, Harbin Institute of Technology, Harbin 150080, China.
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11
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Liu HY, Chen WL, Ober CK, Daniel S. Biologically Complex Planar Cell Plasma Membranes Supported on Polyelectrolyte Cushions Enhance Transmembrane Protein Mobility and Retain Native Orientation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:1061-1072. [PMID: 29020444 DOI: 10.1021/acs.langmuir.7b02945] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Reconstituted supported lipid bilayers (SLB) are widely used as in vitro cell-surface models because they are compatible with a variety of surface-based analytical techniques. However, one of the challenges of using SLBs as a model of the cell surface is the limited complexity in membrane composition, including the incorporation of transmembrane proteins and lipid diversity that may impact the activity of those proteins. Additionally, it is challenging to preserve the transmembrane protein native orientation, function, and mobility in SLBs. Here, we leverage the interaction between cell plasma membrane vesicles and polyelectrolyte brushes to create planar bilayers from cell plasma membrane vesicles that have budded from the cell surface. This approach promotes the direct incorporation of membrane proteins and other species into the planar bilayer without using detergent or reconstitution and preserves membrane constituents. Furthermore, the structure of the polyelectrolyte brush serves as a cushion between the planar bilayer and rigid supporting surface, limiting the interaction of the cytosolic domains of membrane proteins with this surface. Single particle tracking was used to analyze the motion of GPI-linked yellow fluorescent proteins (GPI-YFP) and neon-green fused transmembrane P2X2 receptors (P2X2-neon) and shows that this platform retains over 75% mobility of multipass transmembrane proteins in its native membrane environment. An enzyme accessibility assay confirmed that the protein orientation is preserved and results in the extracellular domain facing toward the bulk phase and the cytosolic side facing the support. Because the platform presented here retains the complexity of the cell plasma membrane and preserves protein orientation and mobility, it is a better representative mimic of native cell surfaces, which may find many applications in biological assays aimed at understanding cell membrane phenomena.
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Affiliation(s)
- Han-Yuan Liu
- Robert F. Smith School of Chemical and Biomolecular Engineering, ‡Department of Material Science and Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Wei-Liang Chen
- Robert F. Smith School of Chemical and Biomolecular Engineering, ‡Department of Material Science and Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Christopher K Ober
- Robert F. Smith School of Chemical and Biomolecular Engineering, ‡Department of Material Science and Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Susan Daniel
- Robert F. Smith School of Chemical and Biomolecular Engineering, ‡Department of Material Science and Engineering, Cornell University , Ithaca, New York 14853, United States
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12
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Barragán Vidal IA, Müller M. Generalization of the swelling method to measure the intrinsic curvature of lipids. J Chem Phys 2017; 147:224902. [PMID: 29246037 DOI: 10.1063/1.5001858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Via computer simulation of a coarse-grained model of two-component lipid bilayers, we compare two methods of measuring the intrinsic curvatures of the constituting monolayers. The first one is a generalization of the swelling method that, in addition to the assumption that the spontaneous curvature linearly depends on the composition of the lipid mixture, incorporates contributions from its elastic energy. The second method measures the effective curvature-composition coupling between the apposing leaflets of bilayer structures (planar bilayers or cylindrical tethers) to extract the spontaneous curvature. Our findings demonstrate that both methods yield consistent results. However, we highlight that the two-leaflet structure inherent to the latter method has the advantage of allowing measurements for mixed lipid systems up to their critical point of demixing as well as in the regime of high concentration (of either species).
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Affiliation(s)
- I A Barragán Vidal
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - M Müller
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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13
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Teske N, Sibold J, Schumacher J, Teiwes NK, Gleisner M, Mey I, Steinem C. Continuous Pore-Spanning Lipid Bilayers on Silicon Oxide-Coated Porous Substrates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:14175-14183. [PMID: 29148811 DOI: 10.1021/acs.langmuir.7b02727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A number of techniques has been developed and analyzed in recent years to generate pore-spanning membranes (PSMs). While quite a number of methods rely on nanoporous substrates, only a few use micrometer-sized pores to be able to individually resolve suspending membranes by means of fluorescence microscopy. To be able to produce PSMs on pores that are micrometer in size, an orthogonal functionalization strategy resulting in a hydrophilic surface is highly desirable. Here, we report on a method to prepare PSMs based on the evaporation of a thin layer of silicon monoxide on top of the porous substrate. PM-IRRAS experiments demonstrate that the final surface is composed of SiOx with 1 < x < 2. The hydrophilic surface turned out to be well suited to spread giant unilamellar vesicles forming PSMs. As the method does not rely on a gold coating as frequently used for orthogonal functionalization, fluorescence micrographs provide information not only from the freestanding membrane areas but also from the supported ones. The observation of the entire PSM area enabled us to observe phase-separation in these membranes on the freestanding and supported parts as well as protein binding and possible lipid reorganization of the membranes induced by binding of the protein Shiga toxin.
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Affiliation(s)
- Nelli Teske
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
| | - Jeremias Sibold
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
| | - Johannes Schumacher
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
| | - Nikolas K Teiwes
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
| | - Martin Gleisner
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Göttingen , Tammannstraße 2, 37077 Göttingen, Germany
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14
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Liu HY, Grant H, Hsu HL, Sorkin R, Bošković F, Wuite G, Daniel S. Supported Planar Mammalian Membranes as Models of in Vivo Cell Surface Architectures. ACS APPLIED MATERIALS & INTERFACES 2017; 9:35526-35538. [PMID: 28930438 DOI: 10.1021/acsami.7b07500] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Emerging technologies use cell plasma membrane vesicles or "blebs" as an intermediate to form molecularly complete, planar cell surface mimetics that are compatible with a variety of characterization tools and microscopy methods. This approach enables direct incorporation of membrane proteins into supported lipid bilayers without using detergents and reconstitution and preserves native lipids and membrane species. Such a system can be advantageous as in vitro models of in vivo cell surfaces for study of the roles of membrane proteins as drug targets in drug delivery, host-pathogen interactions, tissue engineering, and many other bioanalytical and sensing applications. However, the impact of methods used to induce cell blebbing (vesiculation) on protein and membrane properties is still unknown. This study focuses on characterization of cell blebs created under various bleb-inducing conditions and the result on protein properties (orientation, mobility, activity, etc.) and lipid scrambling in this platform. The orientation of proteins in the cell blebs and planar bilayers is revealed using a protease cleavage assay. Lipid scrambling in both cell blebs and planar bilayers is indicated through an annexin V binding assay. To quantify protein confinement, immobility, etc., incorporation of GPI-linked yellow fluorescent protein (GPI-YFP) was used in conjunction with single-molecule tracking (SMT) microscopy. Finally, to investigate the impact of the bleb induction method on protein activity and expression level, cell blebs expressing human aminopeptidase N (hAPN) were analyzed by an enzyme activity assay and immunoblotting. This work enriches our understanding of cell plasma membrane bleb bilayers as a biomimetic platform, reveals conditions under which specific properties are met, and represents one of the few ways to make molecularly complete supported bilayers directly from cell plasma membranes.
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Affiliation(s)
- Han-Yuan Liu
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Hannah Grant
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Hung-Lun Hsu
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
| | - Raya Sorkin
- Department of Physics and Astronomy and Laser Lab, Vrije Universiteit Amsterdam , Amsterdam 1081 HV, The Netherlands
| | - Filip Bošković
- Department of Physics and Astronomy and Laser Lab, Vrije Universiteit Amsterdam , Amsterdam 1081 HV, The Netherlands
| | - Gijs Wuite
- Department of Physics and Astronomy and Laser Lab, Vrije Universiteit Amsterdam , Amsterdam 1081 HV, The Netherlands
| | - Susan Daniel
- School of Chemical and Biomolecular Engineering, Cornell University , Ithaca, New York 14853, United States
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15
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Wen C, Wan M, Li X, He Q, Gao L, Fang W. Formation Mechanism and Properties of Polyelectrolyte Multilayer-Supported Lipid Bilayers: A Coarse-Grained Molecular Dynamics Study. ACS OMEGA 2017; 2:910-917. [PMID: 31457479 PMCID: PMC6641172 DOI: 10.1021/acsomega.7b00198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/02/2017] [Indexed: 06/01/2023]
Abstract
Polyelectrolyte multilayer (PEM)-supported lipid bilayers (SLBs) that connect with functional proteins are popular models for cell membranes and are usually obtained via vesicle adsorption and spreading. However, the exact mechanism by which SLBs are formed is not fully understood. In this study, we employ coarse-grained molecular dynamics simulations to investigate the pathways by which vesicles undergo spreading upon the deposition on PEM-cushioned substrates. The substrates consist of positive chitosan (CHI)/negative alginate (ALG) multilayers. We find that an isolated vesicle tends to completely disintegrate upon deposition, forming a well-ordered lipid bilayer at appropriate polymer ionic strengths by a mechanism described as "parachute" model. Lipids from the vesicle's outer leaflet are predominantly oriented toward the bulk after the formation of the SLB. The PEM cushion provides adsorption energy of 26.9 kJ mol-1 per lipid for the SLBs. The process by which SLBs are formed is almost independent of the number of layers of CHI/ALG in the PEM cushion. Additional simulations on vesicle clusters also demonstrate that the formation of SLBs can be catalyzed by either neighboring vesicles or preexisting bilayer edges on the support. Moreover, our simulations show that SLBs created on PEM supports preserve the lateral mobility and the symmetric density profile of the phospholipids, as in a freestanding bilayer.
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Affiliation(s)
- Caixia Wen
- Key
Laboratory of Theoretical and Computational Photochemistry, Ministry
of Education, College of Chemistry, Beijing
Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China
| | - Mingwei Wan
- Key
Laboratory of Theoretical and Computational Photochemistry, Ministry
of Education, College of Chemistry, Beijing
Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China
| | - Xiaoxu Li
- Key
Laboratory of Theoretical and Computational Photochemistry, Ministry
of Education, College of Chemistry, Beijing
Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China
| | - Qiang He
- Key
Laboratory for Microsystems and Microstructures Manufacturing, Micro/Nanotechnology
Research Center, Harbin Institute of Technology, Yi Kuang Street 2, Harbin 150080, China
| | - Lianghui Gao
- Key
Laboratory of Theoretical and Computational Photochemistry, Ministry
of Education, College of Chemistry, Beijing
Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China
| | - Weihai Fang
- Key
Laboratory of Theoretical and Computational Photochemistry, Ministry
of Education, College of Chemistry, Beijing
Normal University, 19 Xin-Jie-Kou-Wai Street, Beijing 100875, China
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16
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Kong X, Lu D, Wu J, Liu Z. A theoretical study on the morphological phase diagram of supported lipid bilayers. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp03383d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A morphological phase diagram is constructed using classical density function theory (CDFT).
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Affiliation(s)
- Xian Kong
- Key Laboratory of Industrial Biocatalysis
- Chinese Ministry of Education and Department of Chemical Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Diannan Lu
- Key Laboratory of Industrial Biocatalysis
- Chinese Ministry of Education and Department of Chemical Engineering
- Tsinghua University
- Beijing 100084
- China
| | - Jianzhong Wu
- Department of Chemical and Environmental Engineering
- University of California
- Riverside, California 92521
- USA
| | - Zheng Liu
- Key Laboratory of Industrial Biocatalysis
- Chinese Ministry of Education and Department of Chemical Engineering
- Tsinghua University
- Beijing 100084
- China
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17
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Mannelli I, Sagués F, Pruneri V, Reigada R. Lipid Vesicle Interaction with Hydrophobic Surfaces: A Coarse-Grained Molecular Dynamics Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:12632-12640. [PMID: 27808519 DOI: 10.1021/acs.langmuir.6b03364] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Active surfaces are presently tailored to cause specific effects on living cells, which can be useful in many fields. Their development requires the understanding of the molecular mechanisms of interaction between lipid-enveloped entities and solid surfaces. Here, using coarse-grained molecular dynamics simulations, we have analyzed the different interaction modes of coated substrates with lipid vesicles that mimic biological envelopes. For neutral and hydrophobically functionalized substrates, three action modes on contacting vesicles have been obtained including intact, partially broken, and completely destroyed vesicles. The molecular mechanisms for each interaction pathway and the corresponding energy balances have been analyzed in detail. Interestingly, we have shown that any specific action mode can be obtained by appropriately tailoring the wetting characteristics of the surface coating. In particular, we have shown that surfaces that are simultaneously hydrophobic and oleophilic are optimal to fully disrupt the contacting vesicle lipid bilayer.
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Affiliation(s)
- Ilaria Mannelli
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology , Castelldefels Barcelona 08860, Spain
| | | | - Valerio Pruneri
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology , Castelldefels Barcelona 08860, Spain
- ICREA-Institució Catalana de Recerca i Estudis Avançats , Passeig Lluís Companys, 23, 08010 Barcelona, Spain
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18
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Yang YL, Tsao HK, Sheng YJ. Solid-supported polymer bilayers formed by coil-coil block copolymers. SOFT MATTER 2016; 12:6442-6450. [PMID: 27418114 DOI: 10.1039/c6sm00741d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The formation and physical properties of solid-supported polymer bilayers (SPBs) on an adhesive substrate have been explored by dissipative particle dynamics simulations. A SPB is developed by the adsorption of vesicles formed by diblock copolymers in a selective solvent. The adsorbed vesicle can remain intact or become ruptured into a SPB, depending on the interaction between solvophobic blocks and solvent and the interaction between solvophilic blocks and the substrate. The morphological phase diagram of adsorbed vesicles is acquired. The influence of polymer adhesion strength and solvophobicity on the geometrical and mechanical properties of a SPB is systematically studied as well. It is found that vesicular disruption is easily triggered for strong adhesion strength. Moreover, for strong adhesion strength and weak solvophobicity, the fluctuation of membrane height is impeded while the area of fluctuation is enhanced.
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Affiliation(s)
- Yan-Ling Yang
- Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan 106, Republic of China.
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19
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Kong X, Lu D, Wu J, Liu Z. Spreading of a Unilamellar Liposome on Charged Substrates: A Coarse-Grained Molecular Simulation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3785-3793. [PMID: 27019394 DOI: 10.1021/acs.langmuir.6b00043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Supported lipid bilayers (SLBs) are able to accommodate membrane proteins useful for diverse biomimetic applications. Although liposome spreading represents a common procedure for preparation of SLBs, the underlying mechanism is not yet fully understood, particularly from a molecular perspective. The present study examines the effects of the substrate charge on unilamellar liposome spreading on the basis of molecular dynamics simulations for a coarse-grained model of the solvent and lipid molecules. Liposome transformation into a lipid bilayer of different microscopic structures suggests three types of kinetic pathways depending on the substrate charge density, that is, top-receding, parachute, and parachute with wormholes. Each pathway leads to a unique distribution of the lipid molecules and thereby distinctive properties of SLBs. An increase of the substrate charge density results in a magnified asymmetry of the SLBs in terms of the ratio of charged lipids, parallel surface movements, and the distribution of lipid molecules. While the lipid mobility in the proximal layer is strongly correlated with the substrate potential, the dynamics of lipid molecules in the distal monolayer is similar to that of a freestanding lipid bilayer. For liposome spreading on a highly charged surface, wormhole formation promotes lipid exchange between the SLB monolayers thus reduces the asymmetry on the number density of lipid molecules, the lipid order parameter, and the monolayer thickness. The simulation results reveal the important regulatory role of electrostatic interactions on liposome spreading and the properties of SLBs.
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Affiliation(s)
- Xian Kong
- Key Laboratory of Industrial Biocatalysis, Chinese Ministry of Education and Department of Chemical Engineering, Tsinghua University , Beijing 100084, China
| | - Diannan Lu
- Key Laboratory of Industrial Biocatalysis, Chinese Ministry of Education and Department of Chemical Engineering, Tsinghua University , Beijing 100084, China
| | - Jianzhong Wu
- Department of Chemical and Environmental Engineering, University of California , Riverside California 92521, United States
| | - Zheng Liu
- Key Laboratory of Industrial Biocatalysis, Chinese Ministry of Education and Department of Chemical Engineering, Tsinghua University , Beijing 100084, China
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20
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Richards MJ, Hsia CY, Singh RR, Haider H, Kumpf J, Kawate T, Daniel S. Membrane Protein Mobility and Orientation Preserved in Supported Bilayers Created Directly from Cell Plasma Membrane Blebs. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:2963-74. [PMID: 26812542 DOI: 10.1021/acs.langmuir.5b03415] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Membrane protein interactions with lipids are crucial for their native biological behavior, yet traditional characterization methods are often carried out on purified protein in the absence of lipids. We present a simple method to transfer membrane proteins expressed in mammalian cells to an assay-friendly, cushioned, supported lipid bilayer platform using cell blebs as an intermediate. Cell blebs, expressing either GPI-linked yellow fluorescent proteins or neon-green fused transmembrane P2X2 receptors, were induced to rupture on glass surfaces using PEGylated lipid vesicles, which resulted in planar supported membranes with over 50% mobility for multipass transmembrane proteins and over 90% for GPI-linked proteins. Fluorescent proteins were tracked, and their diffusion in supported bilayers characterized, using single molecule tracking and moment scaling spectrum (MSS) analysis. Diffusion was characterized for individual proteins as either free or confined, revealing details of the local lipid membrane heterogeneity surrounding the protein. A particularly useful result of our bilayer formation process is the protein orientation in the supported planar bilayer. For both the GPI-linked and transmembrane proteins used here, an enzymatic assay revealed that protein orientation in the planar bilayer results in the extracellular domains facing toward the bulk, and that the dominant mode of bleb rupture is via the "parachute" mechanism. Mobility, orientation, and preservation of the native lipid environment of the proteins using cell blebs offers advantages over proteoliposome reconstitution or disrupted cell membrane preparations, which necessarily result in significant scrambling of protein orientation and typically immobilized membrane proteins in SLBs. The bleb-based bilayer platform presented here is an important step toward integrating membrane proteomic studies on chip, especially for future studies aimed at understanding fundamental effects of lipid interactions on protein activity and the roles of membrane proteins in disease pathways.
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Affiliation(s)
- Mark J Richards
- School of Chemical and Biomolecular Engineering, and ‡Department of Molecular Medicine, Cornell University , Ithaca, New York 14853, United States
| | - Chih-Yun Hsia
- School of Chemical and Biomolecular Engineering, and ‡Department of Molecular Medicine, Cornell University , Ithaca, New York 14853, United States
| | - Rohit R Singh
- School of Chemical and Biomolecular Engineering, and ‡Department of Molecular Medicine, Cornell University , Ithaca, New York 14853, United States
| | - Huma Haider
- School of Chemical and Biomolecular Engineering, and ‡Department of Molecular Medicine, Cornell University , Ithaca, New York 14853, United States
| | - Julia Kumpf
- School of Chemical and Biomolecular Engineering, and ‡Department of Molecular Medicine, Cornell University , Ithaca, New York 14853, United States
| | - Toshimitsu Kawate
- School of Chemical and Biomolecular Engineering, and ‡Department of Molecular Medicine, Cornell University , Ithaca, New York 14853, United States
| | - Susan Daniel
- School of Chemical and Biomolecular Engineering, and ‡Department of Molecular Medicine, Cornell University , Ithaca, New York 14853, United States
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21
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Tian F, Yue T, Dong W, Zhang X. Membrane tube pearling induced by a coupling of osmotic pressure and nanoparticle adhesion. Mol Phys 2016. [DOI: 10.1080/00268976.2016.1161855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Falin Tian
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, China
- Laboratoire de Chimie, Ecole Normale Superieure de Lyon, Lyon Cedex, France
| | - Tongtao Yue
- State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, China
| | - Wei Dong
- Laboratoire de Chimie, Ecole Normale Superieure de Lyon, Lyon Cedex, France
| | - Xianren Zhang
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, China
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22
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Yue T, Tian F, Sun M, Zhang X, Huang F. Inter-tube adhesion mediates a new pearling mechanism. Phys Chem Chem Phys 2016; 18:361-74. [PMID: 26616465 DOI: 10.1039/c5cp04579g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A common mechanism for intracellular transport is the controlled shape transformation, also known as pearling, of membrane tubes. Exploring how tube pearling takes place is thus of quite importance to not only understand the bio-functions of tubes, but also promote their potential biomedical applications. While the pearling mechanism of one single tube is well understood, both the pathway and the mechanism of pearling of multiple tubes still remain unclear. Herein, by means of computer simulations we show that the tube pearling can be mediated by the inter-tube adhesion. By increasing the inter-tube adhesion strength, each tube undergoes a discontinuous transition from no pearling to thorough pearling. The discontinuous pearling transition is ascribed to the competitive variation between tube surface tension and the extent of inter-tube adhesion. Besides, the final pearling instability is also affected by tube diameter and inter-tube orientation. Thinner tubes undergo inter-tube lipid diffusion before completion of pearling. The early lipid diffusion reduces the extent of inter-tube adhesion and thus restrains the subsequent pearling. Therefore, only partial or no pearling can take place for two thinner tubes. For two perpendicular tubes, the pearling is also observed, but with different pathways and higher efficiency. The finite size effect is discussed by comparing the pearling of tubes with different lengths. It is expected that this work will not only provide new insights into the mechanism of membrane tube pearling, but also shed light on the potential applications in biomaterials science and nanomedicine.
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Affiliation(s)
- Tongtao Yue
- State Key Laboratory of Heavy Oil Processing, Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao, 266580, China.
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23
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Barragán Vidal IA, Rosetti CM, Pastorino C, Müller M. Measuring the composition-curvature coupling in binary lipid membranes by computer simulations. J Chem Phys 2015; 141:194902. [PMID: 25416907 DOI: 10.1063/1.4901203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The coupling between local composition fluctuations in binary lipid membranes and curvature affects the lateral membrane structure. We propose an efficient method to compute the composition-curvature coupling in molecular simulations and apply it to two coarse-grained membrane models-a minimal, implicit-solvent model and the MARTINI model. Both the weak-curvature behavior that is typical for thermal fluctuations of planar bilayer membranes as well as the strong-curvature regime corresponding to narrow cylindrical membrane tubes are studied by molecular dynamics simulation. The simulation results are analyzed by using a phenomenological model of the thermodynamics of curved, mixed bilayer membranes that accounts for the change of the monolayer area upon bending. Additionally the role of thermodynamic characteristics such as the incompatibility between the two lipid species and asymmetry of composition are investigated.
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Affiliation(s)
- I A Barragán Vidal
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - C M Rosetti
- Centro de Investigaciones en Química Biológica de Córdoba, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
| | - C Pastorino
- Departamento de Física de la Materia Condensada, Centro Atómico Constituyentes, CNEA/CONICET, Av. Gral. Paz 1499, 1650 Pcia. de Buenos Aires, Argentina
| | - M Müller
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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24
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Mattila JP, Shnyrova AV, Sundborger AC, Hortelano ER, Fuhrmans M, Neumann S, Müller M, Hinshaw JE, Schmid SL, Frolov VA. A hemi-fission intermediate links two mechanistically distinct stages of membrane fission. Nature 2015; 524:109-113. [PMID: 26123023 PMCID: PMC4529379 DOI: 10.1038/nature14509] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/05/2015] [Indexed: 12/22/2022]
Abstract
Fusion and fission drive all vesicular transport. Although topologically opposite, these reactions pass through the same hemi-fusion/fission intermediate1,2, characterized by a ‘stalk’ in which only the inner monolayers of the two compartments have merged to form a localized non-bilayer connection1-3. Formation of the hemi-fission intermediate requires energy input from proteins catalyzing membrane remodeling; however the relationship between protein conformational rearrangements and hemi-fusion/fission remains obscure. Here we analyzed how the GTPase cycle of dynamin, the prototypical membrane fission catalyst4-6, is directly coupled to membrane remodeling. We used intra-molecular chemical cross-linking to stabilize dynamin in its GDP•AlF4--bound transition-state. In the absence of GTP this conformer produced stable hemi-fission, but failed to progress to complete fission, even in the presence of GTP. Further analysis revealed that the pleckstrin homology domain (PHD) locked in its membrane-inserted state facilitated hemi-fission. A second mode of dynamin activity, fueled by GTP hydrolysis, couples dynamin disassembly with cooperative diminishing of the PHD wedging, thus destabilizing the hemi-fission intermediate to complete fission. Molecular simulations corroborate the bimodal character of dynamin action and indicate radial and axial forces as dominant, although not independent drivers of hemi-fission and fission transformations, respectively. Mirrored in the fusion reaction7-8, the force bimodality might constitute a general paradigm for leakage-free membrane remodeling.
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Affiliation(s)
- Juha-Pekka Mattila
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75201
| | - Anna V Shnyrova
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of The Basque Country, Leioa, Spain
| | - Anna C Sundborger
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892
| | - Eva Rodriguez Hortelano
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of The Basque Country, Leioa, Spain
| | - Marc Fuhrmans
- Institute for Theoretical Physics, Georg-August University, 37077 Göttingen, Germany
| | - Sylvia Neumann
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Marcus Müller
- Institute for Theoretical Physics, Georg-August University, 37077 Göttingen, Germany
| | - Jenny E Hinshaw
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892
| | - Sandra L Schmid
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75201
| | - Vadim A Frolov
- Biophysics Unit (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of The Basque Country, Leioa, Spain.,IKERBASQUE, Basque Foundation of Science, Bilbao, Spain
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25
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Léonforte F, Müller M. Poly(N-isopropylacrylamide)-Based Mixed Brushes: A Computer Simulation Study. ACS APPLIED MATERIALS & INTERFACES 2015; 7:12450-12462. [PMID: 25634688 DOI: 10.1021/am5076309] [Citation(s) in RCA: 22] [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
Temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM) polymer brushes of fixed molecular weight and grafting density are modeled in the framework of a coarse-grained model with soft, nonbonded interactions and an implicit solvent. This model has been developed to address experimentally relevant, large invariant degrees of polymerization, and nonbonded interactions are expressed via a third-order (virial) expansion of the equation of state. The choice of interaction parameters is intended to mimic the swelling behavior of PNIPAM in water as the temperature increases toward the lower critical solution temperature (T(LCST)). Results of molecular dynamics simulations for one component brushes are compared to experimental data. Mixed brushes incorporating small and large amounts of grafted poly(ethylene glycol) polymers are then considered. The effects of mixing polymer components on the response of the mixed brushes to temperature changes are monitored, and the results are compared to experimental data. In the end, two design principles for biomolecule triggering using temperature-sensitive mixed polymer brushes with functional and switchable end-groups are proposed and studied. This work is in favor of establishing qualitative rules for the design, optimization, and comprehension of binary polymer brushes for bioengineering purposes.
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Affiliation(s)
- Fabien Léonforte
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Marcus Müller
- Institut für Theoretische Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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26
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Fuhrmans M, Müller M. Coarse-grained simulation of dynamin-mediated fission. SOFT MATTER 2015; 11:1464-1480. [PMID: 25523542 DOI: 10.1039/c4sm02533d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Fission is a process in which a region of a lipid bilayer is deformed and separated from its host membrane, so that an additional, topologically independent compartment surrounded by a continuous lipid bilayer is formed. It is a fundamental process in the organization of the compartmentalization of living organisms and carefully regulated by a number of membrane-shaping proteins. An important group within these is the dynamin family of proteins that are involved in the final severance of the hourglass-shaped neck, via which the growing compartment remains connected to the main volume until the completion of fission. We present computer simulations testing different hypotheses of how dynamin proteins facilitate fission by constriction and curvature. Our results on constraint-induced fission of cylindrical membrane tubes emphasize the importance of the local creation of positive curvature and reveal a complex picture of fission, in which the topological transformation can become arrested in an intermediate stage if the proteins constituting the fission machinery are not adaptive.
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Affiliation(s)
- Marc Fuhrmans
- Institut für Theoretische Physik, Georg-August Universität, Germany.
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27
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Kataoka-Hamai C, Yamazaki T. Induced rupture of vesicles adsorbed on glass by pore formation at the surface-bilayer interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:1312-1319. [PMID: 25575280 DOI: 10.1021/la5042822] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Supported lipid bilayers (SLBs) are often formed by spontaneous vesicle rupture and fusion on a solid surface. A well-characterized rupture mechanism for isolated vesicles is pore nucleation and expansion in the solution-exposed nonadsorbed area. In contrast, pore formation in the adsorbed bilayer region has not been investigated to date. In this work, we studied the detailed mechanisms of asymmetric rupture of giant unilamellar vesicles (GUVs) adsorbed on glass using fluorescence microscopy. Asymmetric rupture is the pathway where a rupture pore forms in a GUV near the edge of the glass-bilayer interface with high curvature and then expansion of the pore yields a planar bilayer patch. We show that asymmetric rupture occasionally resulted in SLB patches bearing a defect pore. The defect formation probability depended on lipid composition, salt concentration, and pH. Approximately 40% of negatively charged GUVs under physiological conditions formed pore-containing SLB patches, while negatively charged GUVs at low salt concentration or pH 4.0 and positively charged GUVs exhibited a low probability of defect inclusion. The edge of the defect pore was either in contact with (on-edge) or away from (off-edge) the edge of the planar bilayer. On-edge pores were predominantly formed over off-edge defects. Pores initially formed in the glass-adsorbed region before rupture, most frequently in close contact with the edge of the adsorbed region. When a pore formed near the edge of the adsorbed area or when the edge of a pore reached that of the adsorbed area by pore expansion, asymmetric rupture was induced from the defect site. These induced rupture mechanisms yielded SLB patches with an on-edge pore. In contrast, off-edge pores were produced when defect pore generation and subsequent vesicle rupture were uncoupled. The current results demonstrate that pore formation in the surface-adsorbed region of GUVs is not a negligible event.
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Affiliation(s)
- Chiho Kataoka-Hamai
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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28
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Sacchi M, Balleza D, Vena G, Puia G, Facci P, Alessandrini A. Effect of neurosteroids on a model lipid bilayer including cholesterol: An Atomic Force Microscopy study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1258-67. [PMID: 25620773 DOI: 10.1016/j.bbamem.2015.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 12/18/2014] [Accepted: 01/02/2015] [Indexed: 12/20/2022]
Abstract
Amphiphilic molecules which have a biological effect on specific membrane proteins, could also affect lipid bilayer properties possibly resulting in a modulation of the overall membrane behavior. In light of this consideration, it is important to study the possible effects of amphiphilic molecule of pharmacological interest on model systems which recapitulate some of the main properties of the biological plasma membranes. In this work we studied the effect of a neurosteroid, Allopregnanolone (3α,5α-tetrahydroprogesterone or Allo), on a model bilayer composed by the ternary lipid mixture DOPC/bSM/chol. We chose ternary mixtures which present, at room temperature, a phase coexistence of liquid ordered (Lo) and liquid disordered (Ld) domains and which reside near to a critical point. We found that Allo, which is able to strongly partition in the lipid bilayer, induces a marked increase in the bilayer area and modifies the relative proportion of the two phases favoring the Ld phase. We also found that the neurosteroid shifts the miscibility temperature to higher values in a way similarly to what happens when the cholesterol concentration is decreased. Interestingly, an isoform of Allo, isoAllopregnanolone (3β,5α-tetrahydroprogesterone or isoAllo), known to inhibit the effects of Allo on GABAA receptors, has an opposite effect on the bilayer properties.
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Affiliation(s)
- Mattia Sacchi
- Dipartimento di Scienze Fisiche, Matematiche e Informatiche, Via Campi 213/A, 41125 Modena, Italy; CNR - Istituto Nanoscienze, S3, Via Campi 213/A, 41125 Modena, Italy
| | - Daniel Balleza
- CNR - Istituto Nanoscienze, S3, Via Campi 213/A, 41125 Modena, Italy
| | - Giulia Vena
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Via Campi 287, Modena 287, Italy
| | - Giulia Puia
- Dipartimento di Scienze della Vita, Università di Modena e Reggio Emilia, Via Campi 287, Modena 287, Italy
| | - Paolo Facci
- CNR - Istituto di Biofisica, Via De Marini 6, 16149 Genova, Italy
| | - Andrea Alessandrini
- Dipartimento di Scienze Fisiche, Matematiche e Informatiche, Via Campi 213/A, 41125 Modena, Italy; CNR - Istituto Nanoscienze, S3, Via Campi 213/A, 41125 Modena, Italy.
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29
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Fuhrmans M, Marelli G, Smirnova YG, Müller M. Mechanics of membrane fusion/pore formation. Chem Phys Lipids 2015; 185:109-28. [DOI: 10.1016/j.chemphyslip.2014.07.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 07/07/2014] [Accepted: 07/24/2014] [Indexed: 11/27/2022]
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30
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Léonforte F, Müller M. Morphology Modulation of Multicomponent Polymer Brushes in Selective Solvent by Patterned Surfaces. Macromolecules 2014. [DOI: 10.1021/ma502256p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- F. Léonforte
- Institut für Theoretische
Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - M. Müller
- Institut für Theoretische
Physik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
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31
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Alessandrini A, Facci P. Phase transitions in supported lipid bilayers studied by AFM. SOFT MATTER 2014; 10:7145-7164. [PMID: 25090108 DOI: 10.1039/c4sm01104j] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We review the capabilities of Atomic Force Microscopy (AFM) in the study of phase transitions in Supported Lipid Bilayers (SLBs). AFM represents a powerful technique to cover the resolution range not available to fluorescence imaging techniques and where spectroscopic data suggest what the relevant lateral scale for domain formation might be. Phase transitions of lipid bilayers involve the formation of domains characterized by different heights with respect to the surrounding phase and are therefore easily identified by AFM in liquid solution once the bilayer is confined to a flat surface. Even if not endowed with high time resolution, AFM allows light to be shed on some aspects related to lipid phase transitions in the case of both a single lipid component and lipid mixtures containing sterols also. We discuss here the obtained results in light of the peculiarities of supported lipid bilayer model systems.
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Affiliation(s)
- Andrea Alessandrini
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Via Campi 213/A, 41125, Modena, Italy.
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32
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Jackman JA, Choi JH, Zhdanov VP, Cho NJ. Influence of osmotic pressure on adhesion of lipid vesicles to solid supports. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:11375-84. [PMID: 23901837 DOI: 10.1021/la4017992] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The adhesion of lipid vesicles to solid supports represents an important step in the molecular self-assembly of model membrane platforms. A wide range of experimental parameters are involved in controlling this process, including substrate material and topology, lipid composition, vesicle size, solution pH, ionic strength, and osmotic pressure. At present, it is not well understood how the magnitude and direction of the osmotic pressure exerted on a vesicle influence the corresponding adsorption kinetics. In this work, using quartz crystal microbalance with dissipation (QCM-D) monitoring, we have experimentally studied the role of osmotic pressure in the adsorption of zwitterionic vesicles onto silicon oxide. The osmotic pressure was induced by changing the ionic strength of the solvent across an appreciably wider range (from 25 to 1000 mM NaCl outside of the vesicle, and 125 mM NaCl inside of the vesicle, unless otherwise noted) compared to that used in earlier works. Our key finding is demonstration that, by changing osmotic pressure, all three generic types of the kinetics of vesicle adsorption and rupture can be observed in one system, including (i) adsorption of intact vesicles, (ii) adsorption and rupture after reaching a critical vesicle coverage, and (iii) rupture just after adsorption. Furthermore, theoretical analysis of pressure-induced deformation of adsorbed vesicles and a DLVO-type analysis of the vesicle-substrate interaction qualitatively support our observations. Taken together, the findings in this work demonstrate that osmotic pressure can either promote or impede the rupture of adsorbed vesicles on silicon oxide, and offer experimental evidence to support adhesion energy-based models that describe the adsorption and spontaneous rupture of vesicles on solid supports.
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Affiliation(s)
- Joshua A Jackman
- School of Materials Science and Engineering, Nanyang Technological University , 50 Nanyang Avenue 639798, Singapore
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