1
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Jalali P, Nowroozi A, Moradi S, Shahlaei M. Exploration of lipid bilayer mechanical properties using molecular dynamics simulation. Arch Biochem Biophys 2024; 761:110151. [PMID: 39265694 DOI: 10.1016/j.abb.2024.110151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2024] [Revised: 08/22/2024] [Accepted: 09/09/2024] [Indexed: 09/14/2024]
Abstract
Important biological structures known for their exceptional mechanical qualities, lipid bilayers are essential to many cellular functions. Fluidity, elasticity, permeability, stiffness, tensile strength, compressibility, shear viscosity, line tension, and curvature elasticity are some of the fundamental characteristics affecting their behavior. The purpose of this review is to examine these characteristics in more detail by molecular dynamics simulation, elucidating their importance and the elements that lead to their appearance in lipid bilayers. Comprehending the mechanical characteristics of lipid bilayers is critical for creating medications, drug delivery systems, and biomaterials that interact with biological membranes because it allows one to understand how these materials respond to different stresses and deformations. The influence of mechanical characteristics on important lipid bilayer properties is examined in this review. The mechanical properties of lipid bilayers were clarified through the use of molecular dynamics simulation analysis techniques, including bilayer thickness, stress-strain analysis, lipid bilayer area compressibility, membrane bending rigidity, and time- or ensemble-averaged the area per lipid evaluation. We explain the significance of molecular dynamics simulation analysis methods, providing important new information about the stability and dynamic behavior of the bilayer. In the end, we hope to use molecular dynamics simulation to provide a comprehensive understanding of the mechanical properties and behavior of lipid bilayers, laying the groundwork for further studies and applications. Taken together, careful investigation of these mechanical aspects deepens our understanding of the adaptive capacities and functional roles of lipid bilayers in biological environments.
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Affiliation(s)
- Parvin Jalali
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Amin Nowroozi
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Sajad Moradi
- Nano Drug Delivery Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mohsen Shahlaei
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran.
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2
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Pabst G, Heerklotz H. After the gold rush: Getting far from the shallow in studying asymmetric membranes. Biophys J 2024; 123:2355-2357. [PMID: 38902925 PMCID: PMC11365099 DOI: 10.1016/j.bpj.2024.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/10/2024] [Accepted: 06/18/2024] [Indexed: 06/22/2024] Open
Affiliation(s)
- Georg Pabst
- Biophysics, Institute of Molecular Bioscience (IMB), NAWI Graz, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria.
| | - Heiko Heerklotz
- Institute of Pharmaceutical Sciences, University of Freiburg, Freiburg, Germany; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada; BIOSS Signaling Research Center, Freiburg, Germany
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3
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Drabik D, Hinc P, Stephan M, Cavalcanti RRM, Czogalla A, Dimova R. Effect of leaflet asymmetry on the stretching elasticity of lipid bilayers with phosphatidic acid. Biophys J 2024; 123:2406-2421. [PMID: 38822521 PMCID: PMC11365108 DOI: 10.1016/j.bpj.2024.05.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/03/2024] [Accepted: 05/29/2024] [Indexed: 06/03/2024] Open
Abstract
The asymmetry of membranes has a significant impact on their biophysical characteristics and behavior. This study investigates the composition and mechanical properties of symmetric and asymmetric membranes in giant unilamellar vesicles (GUVs) made of palmitoyloleoyl phosphatidylcholine (POPC) and palmitoyloleoyl phosphatidic acid (POPA). A combination of fluorescence quantification, zeta potential measurements, micropipette aspiration, and bilayer molecular dynamics simulations are used to characterize these membranes. The outer leaflet composition in vesicles is found consistent across the two preparation methods we employed, namely electroformation and inverted emulsion transfer. However, characterizing the inner leaflet poses challenges. Micropipette aspiration of GUVs show that oil residues do not substantially alter membrane elasticity, but simulations reveal increased membrane thickness and decreased interleaflet coupling in the presence of oil. Asymmetric membranes with a POPC:POPA mixture in the outer leaflet and POPC in the inner leaflet display similar stretching elasticity values to symmetric POPC:POPA membranes, suggesting potential POPA insertion into the inner leaflet during vesicle formation and suppressed asymmetry. The inverse compositional asymmetry, with POPC in the outer leaflet and POPC:POPA in the inner one yield less stretchable membranes with higher compressibility modulus compared with their symmetric counterparts. Challenges in achieving and predicting compositional correspondence highlight the limitations of phase-transfer-based methods. In addition, caution is advised when using fluorescently labeled lipids (even at low fractions of 0.5 mol %), as unexpected gel-like domains in symmetric POPC:POPA membranes were observed only with a specific type of labeled DOPE (dioleoylphosphatidylethanolamine) and the same fraction of unlabeled DOPE. The latter suggest that such domain formation may result from interactions between lipids and membrane fluorescent probes. Overall, this study underscores the complexity of factors influencing GUV membrane asymmetry, emphasizing the need for further research and improvement of characterization techniques.
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Affiliation(s)
- Dominik Drabik
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland; Max Planck Institute of Colloids and Interfaces, Potsdam, Germany; Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland.
| | - Piotr Hinc
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Mareike Stephan
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany
| | | | - Aleksander Czogalla
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland.
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
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4
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Deserno M. Biomembranes balance many types of leaflet asymmetries. Curr Opin Struct Biol 2024; 87:102832. [PMID: 38735128 DOI: 10.1016/j.sbi.2024.102832] [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: 12/14/2023] [Revised: 03/18/2024] [Accepted: 04/22/2024] [Indexed: 05/14/2024]
Abstract
Many biological membranes host different lipid species in their two leaflets. Since their spontaneous curvatures are typically not the same, this compositional asymmetry generally entails bending torques, which can be counteracted by differential stress-the difference between the two leaflet tensions. This stress, in turn, can affect elastic parameters or phase behavior of the membrane or each individual leaflet, or push easily flippable species, especially cholesterol, from the compressed leaflet into the tense leaflet. In short, breaking the symmetry of a single observable (to wit: composition), essentially breaks all other symmetries as well, with many potentially interesting consequences. This brief report examines the elastic aspects of this interplay, focusing on some elementary conditions of mechanical and thermodynamic equilibrium, but also shows how this poses novel questions that we are only beginning to appreciate.
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Affiliation(s)
- Markus Deserno
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA.
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5
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Gudyka J, Ceja-Vega J, Krmic M, Porteus R, Lee S. The Role of Lipid Intrinsic Curvature in the Droplet Interface Bilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:11428-11435. [PMID: 38764431 PMCID: PMC11155247 DOI: 10.1021/acs.langmuir.4c00270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 05/13/2024] [Accepted: 05/14/2024] [Indexed: 05/21/2024]
Abstract
Model bilayers are constructed from lipids having different intrinsic curvatures using the droplet interface bilayer (DIB) method, and their static physicochemical properties are determined. Geometrical and tensiometric measurements are used to derive the free energy of formation (ΔF) of a two-droplet DIB relative to a pair of isolated aqueous droplets, each decorated with a phospholipid monolayer. The lipid molecules employed have different headgroup sizes but identical hydrophobic tail structure, and each is characterized by an intrinsic curvature value (c0) that increases in absolute value with decreasing size of headgroup. Mixtures of lipids at different ratios were also investigated. The role of curvature stress on the values of ΔF of the respective lipid bilayers in these model membranes is discussed and is illuminated by the observation of a decrement in ΔF that scales as a near linear function of c02. Overall, the results reveal an association that should prove useful in studies of ion channels and other membrane proteins embedded in model droplet bilayer systems that will impact the understanding of protein function in cellular membranes composed of lipids of high and low curvature.
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Affiliation(s)
- Jamie Gudyka
- Department of Chemistry and
Biochemistry, Iona University, New Rochelle, New York 10801, United States
| | - Jasmin Ceja-Vega
- Department of Chemistry and
Biochemistry, Iona University, New Rochelle, New York 10801, United States
| | - Michael Krmic
- Department of Chemistry and
Biochemistry, Iona University, New Rochelle, New York 10801, United States
| | - Riley Porteus
- Department of Chemistry and
Biochemistry, Iona University, New Rochelle, New York 10801, United States
| | - Sunghee Lee
- Department of Chemistry and
Biochemistry, Iona University, New Rochelle, New York 10801, United States
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6
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Landiech S, Elias M, Lapèze P, Ajiyel H, Plancke M, González-Bermúdez B, Laborde A, Mesnilgrente F, Bourrier D, Berti D, Montis C, Mazenq L, Baldo J, Roux C, Delarue M, Joseph P. Parallel on-chip micropipettes enabling quantitative multiplexed characterization of vesicle mechanics and cell aggregates rheology. APL Bioeng 2024; 8:026122. [PMID: 38894959 PMCID: PMC11184969 DOI: 10.1063/5.0193333] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
Micropipette aspiration (MPA) is one of the gold standards for quantifying biological samples' mechanical properties, which are crucial from the cell membrane scale to the multicellular tissue. However, relying on the manipulation of individual home-made glass pipettes, MPA suffers from low throughput and no automation. Here, we introduce the sliding insert micropipette aspiration method, which permits parallelization and automation, thanks to the insertion of tubular pipettes, obtained by photolithography, within microfluidic channels. We show its application both at the lipid bilayer level, by probing vesicles to measure membrane bending and stretching moduli, and at the tissue level by quantifying the viscoelasticity of 3D cell aggregates. This approach opens the way to high-throughput, quantitative mechanical testing of many types of biological samples, from vesicles and individual cells to cell aggregates and explants, under dynamic physico-chemical stimuli.
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Affiliation(s)
| | - Marianne Elias
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Pierre Lapèze
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Hajar Ajiyel
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Marine Plancke
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Blanca González-Bermúdez
- Center for Biomedical Technology, Universidad Politécnica de Madrid, Pozuelo de Alarcón, Spain and Department of Materials Science, ETSI de Caminos, Canales y Puertos, Universidad Politécnica de Madrid, Madrid, Spain
| | - Adrian Laborde
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | | | - David Bourrier
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Debora Berti
- CSGI and Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Costanza Montis
- CSGI and Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Laurent Mazenq
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Jérémy Baldo
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Clément Roux
- SoftMat, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Morgan Delarue
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
| | - Pierre Joseph
- LAAS-CNRS, Université de Toulouse, CNRS, Toulouse, France
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7
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Huster D, Maiti S, Herrmann A. Phospholipid Membranes as Chemically and Functionally Tunable Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2312898. [PMID: 38456771 DOI: 10.1002/adma.202312898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/12/2024] [Indexed: 03/09/2024]
Abstract
The sheet-like lipid bilayer is the fundamental structural component of all cell membranes. Its building blocks are phospholipids and cholesterol. Their amphiphilic structure spontaneously leads to the formation of a bilayer in aqueous environment. Lipids are not just structural elements. Individual lipid species, the lipid membrane structure, and lipid dynamics influence and regulate membrane protein function. An exciting field is emerging where the membrane-associated material properties of different bilayer systems are used in designing innovative solutions for widespread applications across various fields, such as the food industry, cosmetics, nano- and biomedicine, drug storage and delivery, biotechnology, nano- and biosensors, and computing. Here, the authors summarize what is known about how lipids determine the properties and functions of biological membranes and how this has been or can be translated into innovative applications. Based on recent progress in the understanding of membrane structure, dynamics, and physical properties, a perspective is provided on how membrane-controlled regulation of protein functions can extend current applications and even offer new applications.
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Affiliation(s)
- Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16/18, D-04107, Leipzig, Germany
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai, 400 005, India
| | - Andreas Herrmann
- Freie Universität Berlin, Department Chemistry and Biochemistry, SupraFAB, Altensteinstr. 23a, D-14195, Berlin, Germany
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8
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Pabst G, Keller S. Exploring membrane asymmetry and its effects on membrane proteins. Trends Biochem Sci 2024; 49:333-345. [PMID: 38355393 DOI: 10.1016/j.tibs.2024.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/08/2024] [Accepted: 01/19/2024] [Indexed: 02/16/2024]
Abstract
Plasma membranes utilize free energy to maintain highly asymmetric, non-equilibrium distributions of lipids and proteins between their two leaflets. In this review we discuss recent progress in quantitative research enabled by using compositionally controlled asymmetric model membranes. Both experimental and computational studies have shed light on the nuanced mechanisms that govern the structural and dynamic coupling between compositionally distinct bilayer leaflets. This coupling can increase the membrane bending rigidity and induce order - or lipid domains - across the membrane. Furthermore, emerging evidence indicates that integral membrane proteins not only respond to asymmetric lipid distributions but also exhibit intriguing asymmetric properties themselves. We propose strategies to advance experimental research, aiming for a deeper, quantitative understanding of membrane asymmetry, which carries profound implications for cellular physiology.
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Affiliation(s)
- Georg Pabst
- Biophysics, Institute of Molecular Bioscience (IMB), NAWI Graz, University of Graz, Graz 8010, Austria; BioTechMed-Graz, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria.
| | - Sandro Keller
- Biophysics, Institute of Molecular Bioscience (IMB), NAWI Graz, University of Graz, Graz 8010, Austria; BioTechMed-Graz, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria
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9
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Pöhnl M, Trollmann MFW, Böckmann RA. Nonuniversal impact of cholesterol on membranes mobility, curvature sensing and elasticity. Nat Commun 2023; 14:8038. [PMID: 38081812 PMCID: PMC10713574 DOI: 10.1038/s41467-023-43892-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Biological membranes, composed mainly of phospholipids and cholesterol, play a vital role as cellular barriers. They undergo localized reshaping in response to environmental cues and protein interactions, with the energetics of deformations crucial for exerting biological functions. This study investigates the non-universal role of cholesterol on the structure and elasticity of saturated and unsaturated lipid membranes. Our study uncovers a highly cooperative relationship between thermal membrane bending and local cholesterol redistribution, with cholesterol showing a strong preference for the compressed membrane leaflet. Remarkably, in unsaturated membranes, increased cholesterol mobility enhances cooperativity, resulting in membrane softening despite membrane thickening and lipid compression caused by cholesterol. These findings elucidate the intricate interplay between thermodynamic forces and local molecular interactions that govern collective properties of membranes.
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Affiliation(s)
- Matthias Pöhnl
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Marius F W Trollmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- Erlangen National High Perfomance Computing Center (NHR@FAU), Erlangen, Germany
| | - Rainer A Böckmann
- Computational Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
- Erlangen National High Perfomance Computing Center (NHR@FAU), Erlangen, Germany.
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10
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Doktorova M, Levental I, Heberle FA. Seeing the Membrane from Both Sides Now: Lipid Asymmetry and Its Strange Consequences. Cold Spring Harb Perspect Biol 2023; 15:a041393. [PMID: 37604588 PMCID: PMC10691478 DOI: 10.1101/cshperspect.a041393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Almost all biomembranes are constructed as lipid bilayers and, in almost all of these, the two opposing monolayers (leaflets) have distinct lipid compositions. This lipid asymmetry arises through the concerted action of a suite of energy-dependent enzymes that maintain living bilayers in a far-from-equilibrium steady-state. Recent discoveries reveal that lipid compositional asymmetry imparts biophysical asymmetries and that this dualistic organization may have major consequences for cellular physiology. Importantly, while transbilayer asymmetry appears to be an essential, near-ubiquitous characteristic of biological membranes, it has been challenging to reproduce in reconstituted or synthetic systems. Although recent methodological developments have overcome some critical challenges, it remains difficult to extrapolate results from available models to biological systems. Concurrently, there are few experimental approaches for targeted, controlled manipulation of lipid asymmetry in living cells. Thus, the biophysical and functional consequences of membrane asymmetry remain almost wholly unexplored. This perspective summarizes the current state of knowledge and highlights emerging themes that are beginning to make inroads into the fundamental question of why life tends toward asymmetry in its bilayers.
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Affiliation(s)
- Milka Doktorova
- Department of Molecular Physiology and Pharmacology, University of Virginia, Center for Membrane and Cell Physiology, Charlottesville, Virginia 22908, USA
| | - Ilya Levental
- Department of Molecular Physiology and Pharmacology, University of Virginia, Center for Membrane and Cell Physiology, Charlottesville, Virginia 22908, USA
| | - Frederick A Heberle
- Department of Chemistry, University of Tennessee Knoxville, Knoxville, Tennessee 37996, USA
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11
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Frewein MPK, Piller P, Semeraro EF, Czakkel O, Gerelli Y, Porcar L, Pabst G. Distributing aminophospholipids asymmetrically across leaflets causes anomalous membrane stiffening. Biophys J 2023; 122:2445-2455. [PMID: 37120716 PMCID: PMC10322881 DOI: 10.1016/j.bpj.2023.04.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/10/2023] [Accepted: 04/25/2023] [Indexed: 05/01/2023] Open
Abstract
We studied the mechanical leaflet coupling of prototypic mammalian plasma membranes using neutron spin-echo spectroscopy. In particular, we examined a series of asymmetric phospholipid vesicles with phosphatidylcholine and sphingomyelin enriched in the outer leaflet and inner leaflets composed of phosphatidylethanolamine/phosphatidylserine mixtures. The bending rigidities of most asymmetric membranes were anomalously high, exceeding even those of symmetric membranes formed from their cognate leaflets. Only asymmetric vesicles with outer leaflets enriched in sphingolipid displayed bending rigidities in conformity with these symmetric controls. We performed complementary small-angle neutron and x-ray experiments on the same vesicles to examine possible links to structural coupling mechanisms, which would show up in corresponding changes in membrane thickness. In addition, we estimated differential stress between leaflets originating either from a mismatch of their lateral areas or spontaneous curvatures. However, no correlation with asymmetry-induced membrane stiffening was observed. To reconcile our findings, we speculate that an asymmetric distribution of charged or H-bond forming lipids may induce an intraleaflet coupling, which increases the weight of hard undulatory modes of membrane fluctuations and hence the overall membrane stiffness.
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Affiliation(s)
- Moritz P K Frewein
- Biophysics, Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, Austria; Institut Laue-Langevin, Grenoble, France; BioTechMed Graz, Graz, Austria; Field of Excellence BioHealth, Graz, Austria
| | - Paulina Piller
- Biophysics, Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria; Field of Excellence BioHealth, Graz, Austria
| | - Enrico F Semeraro
- Biophysics, Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria; Field of Excellence BioHealth, Graz, Austria
| | | | - Yuri Gerelli
- CNR Institute for Complex Systems, Uos Sapienza, Roma, Italy; Department of Physics, Sapienza University of Rome, Roma, Italy
| | | | - Georg Pabst
- Biophysics, Institute of Molecular Biosciences, University of Graz, NAWI Graz, Graz, Austria; BioTechMed Graz, Graz, Austria; Field of Excellence BioHealth, Graz, Austria.
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12
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Krompers M, Heerklotz H. A Guide to Your Desired Lipid-Asymmetric Vesicles. MEMBRANES 2023; 13:267. [PMID: 36984654 PMCID: PMC10054703 DOI: 10.3390/membranes13030267] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/14/2023] [Accepted: 02/18/2023] [Indexed: 06/18/2023]
Abstract
Liposomes are prevalent model systems for studies on biological membranes. Recently, increasing attention has been paid to models also representing the lipid asymmetry of biological membranes. Here, we review in-vitro methods that have been established to prepare free-floating vesicles containing different compositions of the classic two-chain glycero- or sphingolipids in their outer and inner leaflet. In total, 72 reports are listed and assigned to four general strategies that are (A) enzymatic conversion of outer leaflet lipids, (B) re-sorting of lipids between leaflets, (C) assembly from different monolayers and (D) exchange of outer leaflet lipids. To guide the reader through this broad field of available techniques, we attempt to draw a road map that leads to the lipid-asymmetric vesicles that suit a given purpose. Of each method, we discuss advantages and limitations. In addition, various verification strategies of asymmetry as well as the role of cholesterol are briefly discussed. The ability to specifically induce lipid asymmetry in model membranes offers insights into the biological functions of asymmetry and may also benefit the technical applications of liposomes.
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Affiliation(s)
- Mona Krompers
- Department of Pharmaceutical Technology and Biopharmacy, Institute for Pharmaceutical Sciences, University of Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Heiko Heerklotz
- Department of Pharmaceutical Technology and Biopharmacy, Institute for Pharmaceutical Sciences, University of Freiburg, 79104 Freiburg im Breisgau, Germany
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
- Signalling Research Centers BIOSS and CIBSS, University of Freiburg, 79085 Freiburg im Breisgau, Germany
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13
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Compressibility and porosity modulate the mechanical properties of giant gas vesicles. Proc Natl Acad Sci U S A 2023; 120:e2211509120. [PMID: 36649434 PMCID: PMC9942814 DOI: 10.1073/pnas.2211509120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Gas vesicles used as contrast agents for noninvasive ultrasound imaging must be formulated to be stable, and their mechanical properties must be assessed. We report here the formation of perfluoro-n-butane microbubbles coated with surface-active proteins that are produced by filamentous fungi (hydrophobin HFBI from Trichoderma reesei). Using pendant drop and pipette aspiration techniques, we show that these giant gas vesicles behave like glassy polymersomes, and we discover novel gas extraction regimes. We develop a model to analyze the micropipette aspiration of these compressible gas vesicles and compare them to incompressible liquid-filled vesicles. We introduce a sealing parameter to characterize the leakage of gas under aspiration through the pores of the protein coating. Utilizing this model, we can determine the elastic dilatation modulus, surface viscosity, and porosity of the membrane. These results demonstrate the engineering potential of protein-coated bubbles for echogenic and therapeutic applications and extend the use of the pipette aspiration technique to compressible and porous systems.
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14
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Cellular function of (a)symmetric biological membranes. Emerg Top Life Sci 2022; 7:47-54. [PMID: 36562339 DOI: 10.1042/etls20220029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/26/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
In mammalian cells, phospholipids are asymmetrically distributed between the outer and inner leaflets of the plasma membrane. The maintenance of asymmetric phospholipid distribution has been demonstrated to be required for a wide range of cellular functions including cell division, cell migration, and signal transduction. However, we recently reported that asymmetric phospholipid distribution is disrupted in Drosophila cell membranes, and this unique phospholipid distribution leads to the formation of highly deformable cell membranes. In addition, it has become clear that asymmetry in the trans-bilayer distribution of phospholipids is disturbed even in living mammalian cells under certain circumstances. In this article, we introduce our recent studies while focusing on the trans-bilayer distribution of phospholipids, and discuss the cellular functions of (a)symmetric biological membranes.
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15
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Rajabi H, Eraghi SH, Khaheshi A, Toofani A, Hunt C, Wootton RJ. An insect-inspired asymmetric hinge in a double-layer membrane. Proc Natl Acad Sci U S A 2022; 119:e2211861119. [PMID: 36322770 PMCID: PMC9661187 DOI: 10.1073/pnas.2211861119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
Insect wings are deformable airfoils, in which deformations are mostly achieved by complicated interactions between their structural components. Due to the complexity of the wing design and technical challenges associated with testing the delicate wings, we know little about the properties of their components and how they determine wing response to flight forces. Here, we report an unusual structure from the hind-wing membrane of the beetle Pachnoda marginata. The structure, a transverse section of the claval flexion line, consists of two distinguishable layers: a bell-shaped upper layer and a straight lower layer. Our computational simulations showed that this is an effective one-way hinge, which is stiff in tension and upward bending but flexible in compression and downward bending. By systematically varying its design parameters in a computational model, we showed that the properties of the double-layer membrane hinge can be tuned over a wide range. This enabled us to develop a broad design space, which we later used for model selection. We used selected models in three distinct applications, which proved that the double-layer hinge represents a simple yet effective design strategy for controlling the mechanical response of structures using a single material and with no extra mass. The insect-inspired, one-way hinge is particularly useful for developing structures with asymmetric behavior, exhibiting different responses to the same load in two opposite directions. This multidisciplinary study not only advances our understanding of the biomechanics of complicated insect wings but also informs the design of easily tunable engineering hinges.
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Affiliation(s)
- Hamed Rajabi
- Mechanical Intelligence (MI) Research Group, South Bank Applied BioEngineering Research (SABER), School of Engineering, London South Bank University, London SE1 0AA, UK
- Division of Mechanical Engineering and Design, School of Engineering, London South Bank University, London SE1 0AA, UK
- To whom correspondence may be addressed.
| | - Sepehr H. Eraghi
- Mechanical Intelligence (MI) Research Group, South Bank Applied BioEngineering Research (SABER), School of Engineering, London South Bank University, London SE1 0AA, UK
| | - Ali Khaheshi
- Mechanical Intelligence (MI) Research Group, South Bank Applied BioEngineering Research (SABER), School of Engineering, London South Bank University, London SE1 0AA, UK
- Division of Mechanical Engineering and Design, School of Engineering, London South Bank University, London SE1 0AA, UK
| | - Arman Toofani
- Mechanical Intelligence (MI) Research Group, South Bank Applied BioEngineering Research (SABER), School of Engineering, London South Bank University, London SE1 0AA, UK
| | - Cherryl Hunt
- Department of Biosciences, University of Exeter, Exeter EX4 4PY, UK
| | - Robin J. Wootton
- Department of Biosciences, University of Exeter, Exeter EX4 4PY, UK
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16
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Varma M, Deserno M. Distribution of cholesterol in asymmetric membranes driven by composition and differential stress. Biophys J 2022; 121:4001-4018. [PMID: 35927954 PMCID: PMC9674969 DOI: 10.1016/j.bpj.2022.07.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/11/2022] [Accepted: 07/27/2022] [Indexed: 11/25/2022] Open
Abstract
Many lipid membranes of eukaryotic cells are asymmetric, which means the two leaflets differ in at least one physical property, such as lipid composition or lateral stress. Maintaining this asymmetry is helped by the fact that ordinary phospholipids rarely transition between leaflets, but cholesterol is an exception: its flip-flop times are in the microsecond range, so that its distribution between leaflets is determined by a chemical equilibrium. In particular, preferential partitioning can draw cholesterol into a more saturated leaflet, and phospholipid number asymmetry can force it out of a compressed leaflet. Combining highly coarse-grained membrane simulations with theoretical modeling, we investigate how these two driving forces play against each other until cholesterol's chemical potential is equilibrated. The theory includes two coupled elastic sheets and a Flory-Huggins mixing free energy with a χ parameter. We obtain a relationship between χ and the interaction strength between cholesterol and lipids in either of the two leaflets, and we find that it depends, albeit weakly, on lipid number asymmetry. The differential stress measurements under various asymmetry conditions agree with our theoretical predictions. Using the two kinds of asymmetries in combination, we find that it is possible to counteract the phospholipid number bias, and the resultant stress in the membrane, via the control of cholesterol mixing in the leaflets.
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Affiliation(s)
- Malavika Varma
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania.
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17
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Foley SL, Hossein A, Deserno M. Fluid-gel coexistence in lipid membranes under differential stress. Biophys J 2022; 121:2997-3009. [PMID: 35859420 PMCID: PMC9463654 DOI: 10.1016/j.bpj.2022.07.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/03/2022] [Accepted: 07/12/2022] [Indexed: 11/21/2022] Open
Abstract
A widely conserved property of many biological lipid bilayers is their asymmetry. In addition to having distinct compositions on its two sides, a membrane can also exhibit different tensions in its two leaflets, a state known as differential stress. Here, we examine how this stress can influence the phase behavior of the constituent lipid monolayers of a single-component membrane. For temperatures sufficiently close to, but still above, the main transition, molecular dynamics simulations show the emergence of finite gel domains within the compressed leaflet. We describe the thermodynamics of this phenomenon by adding two empirical single-leaflet free energies for the fluid-gel transition, each evaluated at its respective asymmetry-dependent lipid density. Finite size effects arising in simulation are included in the theory through a geometry-dependent interfacial term. Our model reproduces the phase coexistence observed in simulation. It could therefore be used to connect the "hidden variable" of differential stress to experimentally observable properties of the main phase transition. These ideas could be generalized to any first-order bilayer phase transition in the presence of asymmetry, including liquid-ordered/liquid-disordered phase separation.
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Affiliation(s)
- Samuel L Foley
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Amirali Hossein
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania; Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania.
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18
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Effective Antiscaling Performance of ACTF/Nylon 6, 12 Nanofiltration Composite Membrane: Adsorption, Membrane Performance, and Antifouling Property. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2022. [DOI: 10.1007/s13369-021-05969-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Cino EA, Tieleman DP. Curvature-based sorting of eight lipid types in asymmetric buckled plasma membrane models. Biophys J 2022; 121:2060-2068. [PMID: 35524412 DOI: 10.1016/j.bpj.2022.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/13/2022] [Accepted: 05/02/2022] [Indexed: 11/02/2022] Open
Abstract
Curvature is a fundamental property of biological membranes and has essential roles in cellular function. Bending of membranes can be induced by their lipid and protein compositions, as well as peripheral proteins, such as those that make up the cytoskeleton. An important aspect of membrane function is the grouping of lipid species into microdomains, or rafts, which serve as platforms for specific biochemical processes. The fluid mosaic model of membranes has evolved to recognize the importance of curvature and leaflet asymmetry, and there are efforts towards evaluating their functional roles. This work investigates the effect of curvature on the sorting of lipids in buckled asymmetric bilayers containing eight lipid types, approximating an average mammalian plasma membrane, through coarse-grained (CG) molecular dynamics (MD) simulations with the Martini force field. The simulations reveal that i) leaflet compositional asymmetry can induce curvature asymmetry, ii) lipids are sorted by curvature to different extents, and iii) curvature-based partitioning trends show moderate to strong correlations with lipid molecular volumes and head to tail bead ratios, respectively. The findings provide unique insights into the role of curvature in membrane organization, and the curvature-based sorting trends should be useful references for later investigations, and potentially interpreting the functional roles of specific lipids.
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Affiliation(s)
- Elio A Cino
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
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20
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Sun W, Gao X, Lei H, Wang W, Cao Y. Biophysical Approaches for Applying and Measuring Biological Forces. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2105254. [PMID: 34923777 PMCID: PMC8844594 DOI: 10.1002/advs.202105254] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 05/13/2023]
Abstract
Over the past decades, increasing evidence has indicated that mechanical loads can regulate the morphogenesis, proliferation, migration, and apoptosis of living cells. Investigations of how cells sense mechanical stimuli or the mechanotransduction mechanism is an active field of biomaterials and biophysics. Gaining a further understanding of mechanical regulation and depicting the mechanotransduction network inside cells require advanced experimental techniques and new theories. In this review, the fundamental principles of various experimental approaches that have been developed to characterize various types and magnitudes of forces experienced at the cellular and subcellular levels are summarized. The broad applications of these techniques are introduced with an emphasis on the difficulties in implementing these techniques in special biological systems. The advantages and disadvantages of each technique are discussed, which can guide readers to choose the most suitable technique for their questions. A perspective on future directions in this field is also provided. It is anticipated that technical advancement can be a driving force for the development of mechanobiology.
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Affiliation(s)
- Wenxu Sun
- School of SciencesNantong UniversityNantong226019P. R. China
| | - Xiang Gao
- Key Laboratory of Intelligent Optical Sensing and IntegrationNational Laboratory of Solid State Microstructureand Department of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210023P. R. China
- Institute of Brain ScienceNanjing UniversityNanjing210023P. R. China
| | - Hai Lei
- Key Laboratory of Intelligent Optical Sensing and IntegrationNational Laboratory of Solid State Microstructureand Department of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210023P. R. China
- Institute of Brain ScienceNanjing UniversityNanjing210023P. R. China
- Chemistry and Biomedicine Innovation CenterNanjing UniversityNanjing210023P. R. China
| | - Wei Wang
- Key Laboratory of Intelligent Optical Sensing and IntegrationNational Laboratory of Solid State Microstructureand Department of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210023P. R. China
- Institute of Brain ScienceNanjing UniversityNanjing210023P. R. China
| | - Yi Cao
- Key Laboratory of Intelligent Optical Sensing and IntegrationNational Laboratory of Solid State Microstructureand Department of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210023P. R. China
- Institute of Brain ScienceNanjing UniversityNanjing210023P. R. China
- MOE Key Laboratory of High Performance Polymer Materials and TechnologyDepartment of Polymer Science & EngineeringCollege of Chemistry & Chemical EngineeringNanjing UniversityNanjing210023P. R. China
- Chemistry and Biomedicine Innovation CenterNanjing UniversityNanjing210023P. R. China
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21
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Park S, Im W, Pastor RW. Developing initial conditions for simulations of asymmetric membranes: a practical recommendation. Biophys J 2021; 120:5041-5059. [PMID: 34653389 DOI: 10.1016/j.bpj.2021.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/09/2021] [Accepted: 10/08/2021] [Indexed: 01/03/2023] Open
Abstract
It has been proposed that the surface tension difference between leaflets (or differential stress) in asymmetric bilayers is generally nonvanishing. This implies that there is no unique approach to generate initial conditions for simulations of asymmetric bilayers in the absence of experimentally derived constraints. Current generation methods include individual area per lipid (APL) based, leaflet surface area (SA) matching, and zero leaflet tension based (0-DS). This work adds a bilayer-based approach that aims for achieving partial chemical equilibrium by interleaflet switching of selected lipids via P21 periodic boundary conditions. Based on a recently proposed theoretical framework, we obtained expressions for tensions in asymmetric bilayers from both the bending and area strains. We also developed a quantitative measure for the energetic penalty from the differential stress. The impacts of APL-, SA-, and 0-DS-based approaches on mechanical properties are assessed for two different asymmetric bilayers. The lateral pressure profile and its moments differ significantly for each method, whereas the area compressibility modulus is relatively insensitive. Application of P21 periodic boundary conditions (APL/P21, SA/P21, and 0-DS/P21) results in better agreement in mechanical properties between asymmetric bilayers generated by APL-, SA-, and 0-DS-based approaches, in which changes are the smallest for bilayers from the SA-based method. The estimated differential stress from the theory shows good agreement with that from the simulations. These simulation results and the good agreement between the predicted and observed differential stress further support the theoretical framework in which bilayer mechanical properties are outcomes of the interplay between intrinsic bending and asymmetric lipid packing. Based on the simulation results and theoretical predictions, the SA/P21-based, or at least the SA-based (when the differential stress is small), approach is recommended as a practical method for developing initial conditions for asymmetric bilayer simulations.
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Affiliation(s)
- Sooyhung Park
- Department of Biological Sciences, Bethlehem, Pennsylvania; Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania.
| | - Wonpil Im
- Department of Biological Sciences, Bethlehem, Pennsylvania; Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania
| | - Richard W Pastor
- Laboratory of Computational Biology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland
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22
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Zhang G, Sun J. Lipid in Chips: A Brief Review of Liposomes Formation by Microfluidics. Int J Nanomedicine 2021; 16:7391-7416. [PMID: 34764647 PMCID: PMC8575451 DOI: 10.2147/ijn.s331639] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/08/2021] [Indexed: 12/12/2022] Open
Abstract
Liposomes are ubiquitous tools in biomedical applications, such as drug delivery, membrane science and artificial cell. Micro- and nanofabrication techniques have revolutionized the preparation of liposomes on the microscale. State-of-the-art liposomal formation on microfluidic chips and its associated applications are introduced in this review. We attempt to provide a reference for liposomal researchers by comparing various microfluidic techniques for liposomes formation.
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Affiliation(s)
- Guo Zhang
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
| | - Jiaming Sun
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
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23
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Scott HL, Kennison KB, Enoki TA, Doktorova M, Kinnun JJ, Heberle FA, Katsaras J. Model Membrane Systems Used to Study Plasma Membrane Lipid Asymmetry. Symmetry (Basel) 2021; 13. [PMID: 35498375 PMCID: PMC9053528 DOI: 10.3390/sym13081356] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
It is well known that the lipid distribution in the bilayer leaflets of mammalian plasma membranes (PMs) is not symmetric. Despite this, model membrane studies have largely relied on chemically symmetric model membranes for the study of lipid–lipid and lipid–protein interactions. This is primarily due to the difficulty in preparing stable, asymmetric model membranes that are amenable to biophysical studies. However, in the last 20 years, efforts have been made in producing more biologically faithful model membranes. Here, we review several recently developed experimental and computational techniques for the robust generation of asymmetric model membranes and highlight a new and particularly promising technique to study membrane asymmetry.
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Affiliation(s)
- Haden L. Scott
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Kristen B. Kennison
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Thais A. Enoki
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Milka Doktorova
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22903, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Jacob J. Kinnun
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - Frederick A. Heberle
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
| | - John Katsaras
- Shull-Wollan Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Sample Environment Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
- Correspondence: (H.L.S.); (K.B.K.); (T.A.E.); (M.D.); (J.J.K.); (F.A.H.); (J.K.)
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24
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Kumari P, Faraone A, Kelley EG, Benedetto A. Stiffening Effect of the [Bmim][Cl] Ionic Liquid on the Bending Dynamics of DMPC Lipid Vesicles. J Phys Chem B 2021; 125:7241-7250. [PMID: 34169716 PMCID: PMC8279542 DOI: 10.1021/acs.jpcb.1c01347] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The elastic properties of the cellular lipid membrane play a crucial role for life. Their alteration can lead to cell malfunction, and in turn, being able to control them holds the promise of effective therapeutic and diagnostic approaches. In this context, due to their proven strong interaction with lipid bilayers, ionic liquids (ILs)-a vast class of organic electrolytes-may play an important role. This work focuses on the effect of the model imidazolium-IL [bmim][Cl] on the bending modulus of DMPC lipid vesicles, a basic model of cellular lipid membranes. Here, by combining small-angle neutron scattering and neutron spin-echo spectroscopy, we show that the IL, dispersed at low concentrations at the bilayer-water interface, (i) diffuses into the lipid region, accounting for five IL-cations for every 11 lipids, and (ii) causes an increase of the lipid bilayer bending modulus, up to 60% compared to the neat lipid bilayer at 40 °C.
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Affiliation(s)
- Pallavi Kumari
- Department of Sciences, University of Roma Tre, 00146 Rome, Italy.,School of Physics and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland
| | - Antonio Faraone
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Elizabeth G Kelley
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Antonio Benedetto
- Department of Sciences, University of Roma Tre, 00146 Rome, Italy.,School of Physics and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland.,Laboratory for Neutron Scattering, Paul Scherrer Institute, 5232 Villigen, Switzerland
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25
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Shiomi A, Nagao K, Yokota N, Tsuchiya M, Kato U, Juni N, Hara Y, Mori MX, Mori Y, Ui-Tei K, Murate M, Kobayashi T, Nishino Y, Miyazawa A, Yamamoto A, Suzuki R, Kaufmann S, Tanaka M, Tatsumi K, Nakabe K, Shintaku H, Yesylevsky S, Bogdanov M, Umeda M. Extreme deformability of insect cell membranes is governed by phospholipid scrambling. Cell Rep 2021; 35:109219. [PMID: 34107250 DOI: 10.1016/j.celrep.2021.109219] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 04/02/2021] [Accepted: 05/13/2021] [Indexed: 10/21/2022] Open
Abstract
Organization of dynamic cellular structure is crucial for a variety of cellular functions. In this study, we report that Drosophila and Aedes have highly elastic cell membranes with extremely low membrane tension and high resistance to mechanical stress. In contrast to other eukaryotic cells, phospholipids are symmetrically distributed between the bilayer leaflets of the insect plasma membrane, where phospholipid scramblase (XKR) that disrupts the lipid asymmetry is constitutively active. We also demonstrate that XKR-facilitated phospholipid scrambling promotes the deformability of cell membranes by regulating both actin cortex dynamics and mechanical properties of the phospholipid bilayer. Moreover, XKR-mediated construction of elastic cell membranes is essential for hemocyte circulation in the Drosophila cardiovascular system. Deformation of mammalian cells is also enhanced by the expression of Aedes XKR, and thus phospholipid scrambling may contribute to formation of highly deformable cell membranes in a variety of living eukaryotic cells.
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Affiliation(s)
- Akifumi Shiomi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Kohjiro Nagao
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan.
| | - Nobuhiro Yokota
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Masaki Tsuchiya
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Utako Kato
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Naoto Juni
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Yuji Hara
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Masayuki X Mori
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Yasuo Mori
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan
| | - Kumiko Ui-Tei
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Motohide Murate
- UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
| | - Toshihide Kobayashi
- UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
| | - Yuri Nishino
- Graduate School of Life Science, University of Hyogo, Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Atsuo Miyazawa
- Graduate School of Life Science, University of Hyogo, Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Akihisa Yamamoto
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
| | - Ryo Suzuki
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan
| | - Stefan Kaufmann
- Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Motomu Tanaka
- Center for Integrative Medicine and Physics, Institute for Advanced Study, Kyoto University, Kyoto 606-8501, Japan; Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Kazuya Tatsumi
- Department of Mechanical Engineering and Science, Kyoto University, Katsura, Kyoto 615-8540, Japan
| | - Kazuyoshi Nakabe
- Department of Mechanical Engineering and Science, Kyoto University, Katsura, Kyoto 615-8540, Japan
| | - Hirofumi Shintaku
- Microfluidics RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Semen Yesylevsky
- Laboratoire Chrono Environnement UMR CNRS 6249, Université de Bourgogne Franche-Comté, 16 Route de Gray, 25030 Besançon Cedex, France; Department of Physics of Biological Systems, Institute of Physics of the National Academy of Sciences of Ukraine, Prospect Nauky 46, 03680 Kyiv, Ukraine
| | - Mikhail Bogdanov
- Department of Biochemistry & Molecular Biology, University of Texas Health Science Center at Houston, McGovern Medical School, 6431 Fannin, Houston, TX 77030, USA
| | - Masato Umeda
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8510, Japan.
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26
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Liu P, Zabala-Ferrera O, Beltramo PJ. Fabrication and electromechanical characterization of freestanding asymmetric membranes. Biophys J 2021; 120:1755-1764. [PMID: 33675759 PMCID: PMC8204216 DOI: 10.1016/j.bpj.2021.02.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 01/12/2021] [Accepted: 02/24/2021] [Indexed: 01/07/2023] Open
Abstract
All biological cell membranes maintain an electric transmembrane potential of around 100 mV, due in part to an asymmetric distribution of charged phospholipids across the membrane. This asymmetry is crucial to cell health and physiological processes such as intracell signaling, receptor-mediated endocytosis, and membrane protein function. Experimental artificial membrane systems incorporate essential cell membrane structures, such as the phospholipid bilayer, in a controllable manner in which specific properties and processes can be isolated and examined. Here, we describe an approach to fabricate and characterize planar, freestanding, asymmetric membranes and use it to examine the effect of headgroup charge on membrane stiffness. The approach relies on a thin film balance used to form a freestanding membrane by adsorbing aqueous phase lipid vesicles to an oil-water interface and subsequently thinning the oil to form a bilayer. We validate this lipid-in-aqueous approach by analyzing the thickness and compressibility of symmetric membranes with varying zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and anionic 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) sodium salt (DOPG) content as compared with previous lipid-in-oil methods. We find that as the concentration of DOPG increases, membranes become thicker and stiffer. Asymmetric membranes are fabricated by controlling the lipid vesicle composition in the aqueous reservoirs on either side of the oil. Membrane compositional asymmetry is qualitatively demonstrated using a fluorescence quenching assay and quantitatively characterized through voltage-dependent capacitance measurements. Stable asymmetric membranes with DOPC on one side and DOPC-DOPG mixtures on the other were created with transmembrane potentials ranging from 15 to 80 mV. Introducing membrane charge asymmetry decreases both the thickness and stiffness in comparison with symmetric membranes with the same overall phospholipid composition. These initial successes demonstrate a viable pathway to quantitatively characterize asymmetric bilayers that can be extended to accommodate more complex membranes and membrane processes in the future.
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Affiliation(s)
- Paige Liu
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts
| | - Oscar Zabala-Ferrera
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts
| | - Peter J Beltramo
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts.
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Maktabi S, Malmstadt N, Schertzer JW, Chiarot PR. An integrated microfluidic platform to fabricate single-micrometer asymmetric giant unilamellar vesicles (GUVs) using dielectrophoretic separation of microemulsions. BIOMICROFLUIDICS 2021; 15:024112. [PMID: 33912267 PMCID: PMC8064763 DOI: 10.1063/5.0047265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
We present a microfluidic technique that generates asymmetric giant unilamellar vesicles (GUVs) in the size range of 2-14 μm. In our method, we (i) create water-in-oil emulsions as the precursors to build synthetic vesicles, (ii) deflect the emulsions across two oil streams containing different phospholipids at high throughput to establish an asymmetric architecture in the lipid bilayer membranes, and (iii) direct the water-in-oil emulsions across the oil-water interface of an oscillating oil jet in a co-flowing confined geometry to encapsulate the inner aqueous phase inside a lipid bilayer and complete the fabrication of GUVs. In the first step, we utilize a flow-focusing geometry with precisely controlled pneumatic pressures to form monodisperse water-in-oil emulsions. We observed different regimes in forming water-in-oil multiphase flows by changing the applied pressures and discovered a hysteretic behavior in jet breakup and droplet generation. In the second step of GUV fabrication, an oil stream containing phospholipids carries the emulsions into a separation region where we steer the emulsions across two parallel oil streams using active dielectrophoretic and pinched-flow fractionation separations. We explore the effect of applied DC voltage magnitude and carrier oil stream flow rate on the separation efficiency. We develop an image processing code that measures the degree of mixing between the two oil streams as the water-in-oil emulsions travel across them under dielectrophoretic steering to find the ideal operational conditions. Finally, we utilize an oscillating co-flowing jet to complete the formation of asymmetric giant unilamellar vesicles and transfer them to an aqueous phase. We investigate the effect of flow rates on properties of the co-flowing jet oscillating in the whipping mode (i.e., wavelength and amplitude) and define the phase diagram for the oil-in-water jet. Assays used to probe the lipid bilayer membrane of fabricated GUVs showed that membranes were unilamellar, minimal residual oil remained trapped between the two lipid leaflets, and 83% asymmetry was achieved across the lipid bilayers of GUVs.
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Affiliation(s)
| | - Noah Malmstadt
- Departments of Chemical Engineering & Materials Science, Biomedical Engineering, and Chemistry, University of Southern California, Los Angeles, California 90089, USA
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Hossein A, Deserno M. Stiffening transition in asymmetric lipid bilayers: The role of highly ordered domains and the effect of temperature and size. J Chem Phys 2021; 154:014704. [PMID: 33412863 DOI: 10.1063/5.0028255] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cellular membranes consist of a large variety of lipids and proteins, with a composition that generally differs between the two leaflets of the same bilayer. One consequence of this asymmetry is thought to be the emergence of differential stress, i.e., a mismatch in the lateral tension of the two leaflets. This can affect a membrane's mechanical properties; for instance, it can increase the bending rigidity once the differential stress exceeds a critical threshold. Using coarse-grained molecular dynamics simulations based on the MARTINI model, we show that this effect arises due to the formation of more highly ordered domains in the compressed leaflet. The threshold asymmetry increases with temperature, indicating that the transition to a stiffened regime might be restricted to a limited temperature range above the gel transition. We also show that stiffening occurs more readily for larger membranes with smaller typical curvatures, suggesting that the stiffening transition is easier to observe experimentally than in the small-scale systems accessible to simulation.
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Affiliation(s)
- Amirali Hossein
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
| | - Markus Deserno
- Department of Physics, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA
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29
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Affiliation(s)
- Chandra Has
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
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30
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Lipid asymmetry of a model mitochondrial outer membrane affects Bax-dependent permeabilization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183241. [DOI: 10.1016/j.bbamem.2020.183241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/16/2020] [Accepted: 02/12/2020] [Indexed: 11/24/2022]
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31
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Elias M, Dutoya A, Laborde A, Lecestre A, Montis C, Caselli L, Berti D, Lonetti B, Roux C, Joseph P. Microfluidic characterization of biomimetic membrane mechanics with an on-chip micropipette. MICRO AND NANO ENGINEERING 2020. [DOI: 10.1016/j.mne.2020.100064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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32
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Wang X, Tian L, Ren Y, Zhao Z, Du H, Zhang Z, Drinkwater BW, Mann S, Han X. Chemical Information Exchange in Organized Protocells and Natural Cell Assemblies with Controllable Spatial Positions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1906394. [PMID: 32105404 DOI: 10.1002/smll.201906394] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/12/2020] [Indexed: 06/10/2023]
Abstract
An ultrasound-based platform is established to prepare homogenous arrays of giant unilamellar vesicles (GUVs) or red blood cell (RBCs), or hybrid assemblies of GUV/RBCs. Due to different responses to the modulation of the acoustic standing wave pressure field between the GUVs and RBCs, various types of protocell/natural cell hybrid assemblies are prepared with the ability to undergo reversible dynamic reconfigurations from vertical to horizontal alignments, or from 1D to 2D arrangements. A two-step enzymatic cascade reaction between transmitter glucose oxidase-containing GUVs and peroxidase-active receiver RBCs is used to implement chemical signal transduction in the different hybrid micro-arrays. Taken together, the obtained results suggest that the ultrasound-based micro-array technology can be used as an alternative platform to explore chemical communication pathways between protocells and natural cells, providing new opportunities for bottom-up synthetic biology.
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Affiliation(s)
- Xuejing Wang
- State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Liangfei Tian
- Faculty of Engineering, Queens Building, University of Bristol, Bristol, BS8 1TR, UK
- Centre for Protolife Research and Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
| | - Yongshuo Ren
- State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Zhongyang Zhao
- State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
| | - Hang Du
- State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Marine Antifouling Engineering Technology Center of Shandong Province, Weihai, 264209, China
| | - Zhizhou Zhang
- State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Marine Antifouling Engineering Technology Center of Shandong Province, Weihai, 264209, China
| | - Bruce W Drinkwater
- Faculty of Engineering, Queens Building, University of Bristol, Bristol, BS8 1TR, UK
| | - Stephen Mann
- Centre for Protolife Research and Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
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Morshed A, Karawdeniya BI, Bandara Y, Kim MJ, Dutta P. Mechanical characterization of vesicles and cells: A review. Electrophoresis 2020; 41:449-470. [PMID: 31967658 PMCID: PMC7567447 DOI: 10.1002/elps.201900362] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/05/2019] [Accepted: 12/08/2019] [Indexed: 12/30/2022]
Abstract
Vesicles perform many essential functions in all living organisms. They respond like a transducer to mechanical stress in converting the applied force into mechanical and biological responses. At the same time, both biochemical and biophysical signals influence the vesicular response in bearing mechanical loads. In recent years, liposomes, artificial lipid vesicles, have gained substantial attention from the pharmaceutical industry as a prospective drug carrier which can also serve as an artificial cell-mimetic system. The ability of these vesicles to enter through pores of even smaller size makes them ideal candidates for therapeutic agents to reach the infected sites effectively. Engineering of vesicles with desired mechanical properties that can encapsulate drugs and release as required is the prime challenge in this field. This requirement has led to the modifications of the composition of the bilayer membrane by adding cholesterol, sphingomyelin, etc. In this article, we review the manufacturing and characterization techniques of various artificial/synthetic vesicles. We particularly focus on the electric field-driven characterization techniques to determine different properties of vesicle and its membranes, such as bending rigidity, viscosity, capacitance, conductance, etc., which are indicators of their content and mobility. Similarities and differences between artificial vesicles, natural vesicles, and cells are highlighted throughout the manuscript since most of these artificial vesicles are intended for cell mimetic functions.
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Affiliation(s)
- Adnan Morshed
- School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920
| | - Buddini Iroshika Karawdeniya
- Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, Dallas, Texas, USA
| | - Y.M.NuwanD.Y. Bandara
- Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, Dallas, Texas, USA
| | - Min Jun Kim
- Department of Mechanical Engineering, Lyle School of Engineering, Southern Methodist University, Dallas, Texas, USA
| | - Prashanta Dutta
- School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920
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Wang L, Chen W, Guo H, Qian A. Response of membrane tension to gravity in an approximate cell model. Theor Biol Med Model 2019; 16:19. [PMID: 31801614 PMCID: PMC6894217 DOI: 10.1186/s12976-019-0116-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 10/29/2019] [Indexed: 12/03/2022] Open
Abstract
Background Gravity, especially hypergravity, can affect the morphology of membranes, and further influence most biological processes. Since vesicle structures are relatively simple, the vesicle can be treated as a vital model to study the mechanical properties of membranes in most cases. Basic research on membrane tension has become a vital research topic in cellular biomechanics. Methods In this study, a new vesicle model is proposed to quantitatively investigate the response of membrane tension to gravity. In the model, the aqueous lumen inside the vesicle is represented by water, and the vesicle membrane is simplified as a closed, thin, linear elastic shell. Then, the corresponding static equilibrium differential equations of membrane tension are established, and the analytical expression is obtained by the semi-inverse method. The model parameters of the equations are accurately obtained by fitting the reported data, and the values calculated by the model agree well with the reported results. Results The results are as follows: First, both the pseudo-ellipsoidal cap and the pseudo-spherical cap can be used to describe the deformed vesicle model; however, the former can better represent the deformation of the vesicle model because the variance of the pseudo-ellipsoidal cap is smaller. Second, the value of membrane tension is no longer a constant for both models. Interestingly, it varies with the vesicle height under the action of gravity. The closer it is to the substrate, the greater the membrane tension. Finally, the inclination between the tangent and the radial lines at a certain point is nearly proportional to the radius of the cross section in both models. Conclusion These findings may be helpful to study the vesicle model spreading more accurately by taking into account the influence of gravity because it could affect the distribution of membrane tension. Furthermore, it may also provide some guidance for cell spreading and may have some implications for membrane tension-related mechanobiology studies, especially in the hypergravity conditions.
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Affiliation(s)
- Lili Wang
- Shanxi Key Laboratory of Material Strength & Structural Impact, College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.,National Demonstration Center for Experimental Mechanics Education (Taiyuan university of Technology), Taiyuan, 030024, China
| | - Weiyi Chen
- Shanxi Key Laboratory of Material Strength & Structural Impact, College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China. .,National Demonstration Center for Experimental Mechanics Education (Taiyuan university of Technology), Taiyuan, 030024, China.
| | - Hongmei Guo
- Shanxi Key Laboratory of Material Strength & Structural Impact, College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.,National Demonstration Center for Experimental Mechanics Education (Taiyuan university of Technology), Taiyuan, 030024, China
| | - Airong Qian
- Key Laboratory for Space Biosciences & Biotechnology, Faculty of Life Sciences, Northwestern Polytechnical University, Xi'an, 710072, China
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Moga A, Yandrapalli N, Dimova R, Robinson T. Optimization of the Inverted Emulsion Method for High-Yield Production of Biomimetic Giant Unilamellar Vesicles. Chembiochem 2019; 20:2674-2682. [PMID: 31529570 PMCID: PMC6856842 DOI: 10.1002/cbic.201900529] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Indexed: 01/21/2023]
Abstract
In the field of bottom-up synthetic biology, lipid vesicles provide an important role in the construction of artificial cells. Giant unilamellar vesicles (GUVs), due to their membrane's similarity to natural biomembranes, have been widely used as cellular mimics. So far, several methods exist for the production of GUVs with the possibility to encapsulate biological macromolecules. The inverted emulsion-based method is one such technique, which has great potential for rapid production of GUVs with high encapsulation efficiencies for large biomolecules. However, the lack of understanding of various parameters that affect production yields has resulted in sparse adaptation within the membrane and bottom-up synthetic biology research communities. Here, we optimize various parameters of the inverted emulsion-based method to maximize the production of GUVs. We demonstrate that the density difference between the emulsion droplets, oil phase, and the outer aqueous phase plays a crucial role in vesicle formation. We also investigated the impact that centrifugation speed/time, lipid concentration, pH, temperature, and emulsion droplet volume has on vesicle yield and size. Compared to conventional electroformation, our preparation method was not found to significantly alter the membrane mechanical properties. Finally, we optimize the parameters to minimize the time from workbench to microscope and in this way open up the possibility of time-sensitive experiments. In conclusion, our findings will promote the usage of the inverted emulsion method for basic membrane biophysics studies as well as the development of GUVs for use as future artificial cells.
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Affiliation(s)
- Akanksha Moga
- Theory & Bio-Systems DepartmentMax Planck Institute of Colloids and InterfacesPotsdam-Golm Science Park14424PotsdamGermany
| | - Naresh Yandrapalli
- Theory & Bio-Systems DepartmentMax Planck Institute of Colloids and InterfacesPotsdam-Golm Science Park14424PotsdamGermany
| | - Rumiana Dimova
- Theory & Bio-Systems DepartmentMax Planck Institute of Colloids and InterfacesPotsdam-Golm Science Park14424PotsdamGermany
| | - Tom Robinson
- Theory & Bio-Systems DepartmentMax Planck Institute of Colloids and InterfacesPotsdam-Golm Science Park14424PotsdamGermany
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36
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Wang X, Tian L, Du H, Li M, Mu W, Drinkwater BW, Han X, Mann S. Chemical communication in spatially organized protocell colonies and protocell/living cell micro-arrays. Chem Sci 2019; 10:9446-9453. [PMID: 32055320 PMCID: PMC6991169 DOI: 10.1039/c9sc04522h] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 09/11/2019] [Indexed: 12/12/2022] Open
Abstract
Arrays of giant unilamellar vesicles (GUVs) with controllable geometries and occupancies are prepared by acoustic trapping and used to implement chemical signaling in protocell colonies and protocell/living cell consortia.
Micro-arrays of discrete or hemifused giant unilamellar lipid vesicles (GUVs) with controllable spatial geometries, lattice dimensions, trapped occupancies and compositions are prepared by acoustic standing wave patterning, and employed as platforms to implement chemical signaling in GUV colonies and protocell/living cell consortia. The methodology offers an alternative approach to GUV micro-array fabrication and provides new opportunities in protocell research and bottom-up synthetic biology.
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Affiliation(s)
- Xuejing Wang
- State Key Laboratory of Urban Water Resource and Environment , School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin , 150001 , China . .,Centre for Protolife Research and Centre for Organized Matter Chemistry , School of Chemistry University of Bristol , Bristol , BS8 1TS UK .
| | - Liangfei Tian
- Centre for Protolife Research and Centre for Organized Matter Chemistry , School of Chemistry University of Bristol , Bristol , BS8 1TS UK .
| | - Hang Du
- State Key Laboratory of Urban Water Resource and Environment , School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin , 150001 , China .
| | - Mei Li
- Centre for Protolife Research and Centre for Organized Matter Chemistry , School of Chemistry University of Bristol , Bristol , BS8 1TS UK .
| | - Wei Mu
- State Key Laboratory of Urban Water Resource and Environment , School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin , 150001 , China .
| | | | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment , School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin , 150001 , China .
| | - Stephen Mann
- Centre for Protolife Research and Centre for Organized Matter Chemistry , School of Chemistry University of Bristol , Bristol , BS8 1TS UK .
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Steinkühler J, Sezgin E, Urbančič I, Eggeling C, Dimova R. Mechanical properties of plasma membrane vesicles correlate with lipid order, viscosity and cell density. Commun Biol 2019; 2:337. [PMID: 31531398 PMCID: PMC6744421 DOI: 10.1038/s42003-019-0583-3] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 08/15/2019] [Indexed: 11/08/2022] Open
Abstract
Regulation of plasma membrane curvature and composition governs essential cellular processes. The material property of bending rigidity describes the energetic cost of membrane deformations and depends on the plasma membrane molecular composition. Because of compositional fluctuations and active processes, it is challenging to measure it in intact cells. Here, we study the plasma membrane using giant plasma membrane vesicles (GPMVs), which largely preserve the plasma membrane lipidome and proteome. We show that the bending rigidity of plasma membranes under varied conditions is correlated to readout from environment-sensitive dyes, which are indicative of membrane order and microviscosity. This correlation holds across different cell lines, upon cholesterol depletion or enrichment of the plasma membrane, and variations in cell density. Thus, polarity- and viscosity-sensitive probes represent a promising indicator of membrane mechanical properties. Additionally, our results allow for identifying synthetic membranes with a few well defined lipids as optimal plasma membrane mimetics.
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Affiliation(s)
- Jan Steinkühler
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
| | - Erdinc Sezgin
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
| | - Iztok Urbančič
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
- Condensed Matter Physics Department, “Jožef Stefan” Institute, Ljubljana, Slovenia
| | - Christian Eggeling
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, Oxford, OX3 9DS UK
- Institute of Applied Optics Friedrich‐Schiller‐University Jena, Max-Wien Platz 4, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Rumiana Dimova
- Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Science Park Golm, 14424 Potsdam, Germany
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Preparation Methods for Phospholipid Vesicle Arrays and Their Applications in Biological Analysis. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2019. [DOI: 10.1016/s1872-2040(19)61179-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Silva GT, Tian L, Franklin A, Wang X, Han X, Mann S, Drinkwater BW. Acoustic deformation for the extraction of mechanical properties of lipid vesicle populations. Phys Rev E 2019; 99:063002. [PMID: 31330730 DOI: 10.1103/physreve.99.063002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Indexed: 04/30/2023]
Abstract
We use an ultrasonic standing wave to simultaneously trap and deform thousands of soft lipid vesicles immersed in a liquid solution. In our device, acoustic radiation stresses comparable in magnitude to those generated in optical stretching devices are achieved over a spatial extent of more than ten acoustic wavelengths. We solve the acoustic scattering problem in the long-wavelength limit to obtain the radiation stress. The result is then combined with thin-shell elasticity theory to form expressions that relate the deformed geometry to the applied acoustic field intensity. Using observation of the deformed geometry and this model, we rapidly extract mechanical properties, such as the membrane Young's modulus, from populations of lipid vesicles.
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Affiliation(s)
- Glauber T Silva
- Physical Acoustics Group, Instituto de Física, Universidade Federal de Alagoas, Maceió, AL 57072-970, Brazil
| | - Liangfei Tian
- Centre for Protolife Research and Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Amanda Franklin
- Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, United Kingdom
| | - Xuejing Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001, China
| | - Stephen Mann
- Centre for Protolife Research and Centre for Organized Matter Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Bruce W Drinkwater
- Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, United Kingdom
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Maktabi S, Schertzer JW, Chiarot PR. Dewetting-induced formation and mechanical properties of synthetic bacterial outer membrane models (GUVs) with controlled inner-leaflet lipid composition. SOFT MATTER 2019; 15:3938-3948. [PMID: 31011738 PMCID: PMC6647036 DOI: 10.1039/c9sm00223e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The double-membrane cellular envelope of Gram-negative bacteria enables them to endure harsh environments and represents a barrier to many clinically available antibiotics. The outer membrane (OM) is exposed to the environment and is the first point of contact involved in bacterial processes such as signaling, pathogenesis, and motility. As in the cytoplasmic membrane, the OM in Gram-negative bacteria has a phospholipid-rich inner leaflet and an outer leaflet that is predominantly composed of lipopolysaccharide (LPS). We report on a microfluidic technique for fabricating monodisperse asymmetric giant unilamellar vesicles (GUVs) possessing the Gram-negative bacterial OM lipid composition. Our continuous microfluidic fabrication technique generates 50-150 μm diameter water-in-oil-in-water double emulsions at high-throughput. The water-oil and oil-water interfaces facilitate the self-assembly of phospholipid and LPS molecules to create the inner and outer leaflets of the lipid bilayer, respectively. The double emulsions have ultrathin oil shells, which minimizes the amount of residual organic solvent that remains trapped between the leaflets of the GUV membrane. An extraction process by ethanol and micropipette aspiration of the ultrathin oil shells triggers an adhesive interaction between the two lipid monolayers assembled on the water-oil and oil-water interfaces (i.e., dewetting transition), forcing them to contact and form a lipid bilayer membrane. The effect of different inner-leaflet lipid compositions on the emulsion/vesicle stability and the dewetting transition is investigated. We also report on the values for bending and area expansion moduli of synthetic asymmetric model membranes with lipid composition/architecture that is physiologically relevant to the OM in Pseudomonas aeruginosa bacteria.
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Affiliation(s)
- Sepehr Maktabi
- Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, NY, USA.
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Omidvar R, Römer W. Glycan-decorated protocells: novel features for rebuilding cellular processes. Interface Focus 2019; 9:20180084. [PMID: 30842879 PMCID: PMC6388021 DOI: 10.1098/rsfs.2018.0084] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2019] [Indexed: 02/06/2023] Open
Abstract
In synthetic biology approaches, lipid vesicles are widely used as protocell models. While many compounds have been encapsulated in vesicles (e.g. DNA, cytoskeleton and enzymes), the incorporation of glycocalyx components in the lipid bilayer has attracted much less attention so far. In recent years, glycoconjugates have been integrated in the membrane of giant unilamellar vesicles (GUVs). These minimal membrane systems have largely contributed to shed light on the molecular mechanisms of cellular processes. In this review, we first introduce several preparation and biophysical characterization methods of GUVs. Then, we highlight specific applications of protocells investigating glycolipid-mediated endocytosis of toxins, viruses and bacteria. In addition, we delineate how prototissues have been assembled from glycan-decorated protocells by using lectin-mediated cross-linking of opposed glycoreceptors (e.g. glycolipids and glycopeptides). In future applications, glycan-decorated protocells might be useful for investigating cell-cell interactions (e.g. adhesion and communication). We also speculate about the implication of lectin-glycoreceptor interactions in membrane fusion processes.
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Affiliation(s)
- Ramin Omidvar
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
| | - Winfried Römer
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
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42
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Arriaga LR, Huang Y, Kim SH, Aragones JL, Ziblat R, Koehler SA, Weitz DA. Single-step assembly of asymmetric vesicles. LAB ON A CHIP 2019; 19:749-756. [PMID: 30672918 DOI: 10.1039/c8lc00882e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Asymmetric vesicles are membranes in which amphiphiles are asymmetrically distributed between each membrane leaflet. This asymmetry dictates chemical and physical properties of these vesicles, enabling their use as more realistic models of biological cell membranes, which also are asymmetric, and improves their potential for drug delivery and cosmetic applications. However, their fabrication is difficult as the self-assembly of amphiphiles always leads to symmetric vesicles. Here, we report the use of water-in-oil-in-oil-in-water triple emulsion drops to direct the assembly of the two leaflets to form asymmetric vesicles. Different compositions of amphiphiles are dissolved in each of the two oil shells of the triple emulsion; the amphiphiles diffuse to the interfaces and adsorb differentially at each of the two oil/water interfaces of the triple emulsion. These middle oil phases dewet from the innermost water cores of the triple emulsion drops, leading to the formation of membranes with degrees of asymmetry up to 70%. The triple emulsion drops are fabricated using capillary microfluidics, enabling production of highly monodisperse drops at rates as high as 300 Hz. Vesicles produced by this method can very efficiently encapsulate many different ingredients; this further enhances the utility of asymmetric vesicles as artificial cells, bioreactors and delivery vehicles.
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Affiliation(s)
- Laura R Arriaga
- School of Engineering and Applied Science and Department of Physics, Harvard University, 02138 Cambridge, MA, USA.
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Advances in Micropipette Aspiration: Applications in Cell Biomechanics, Models, and Extended Studies. Biophys J 2019; 116:587-594. [PMID: 30683304 DOI: 10.1016/j.bpj.2019.01.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/29/2018] [Accepted: 01/02/2019] [Indexed: 12/31/2022] Open
Abstract
With five decades of sustained application, micropipette aspiration has enabled a wide range of biomechanical studies in the field of cell mechanics. Here, we provide an update on the use of the technique, with a focus on recent developments in the analysis of the experiments, innovative microaspiration-based approaches, and applications in a broad variety of cell types. We first recapitulate experimental variations of the technique. We then discuss analysis models focusing on important limitations of widely used biomechanical models, which underpin the urge to adopt the appropriate ones to avoid misleading conclusions. The possibilities of performing different studies on the same cell are also considered.
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Gera P, Salac D. Three-dimensional multicomponent vesicles: dynamics and influence of material properties. SOFT MATTER 2018; 14:7690-7705. [PMID: 30177985 DOI: 10.1039/c8sm01087k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work, the nonlinear hydrodynamics of a three-dimensional multicomponent vesicle in shear flow are explored. Using a volume- and area-conserving projection method coupled to a gradient-augmented level set and surface phase field method, the dynamics are systematically studied as a function of the membrane bending rigidity difference between the components, the speed of diffusion compared to the underlying shear flow, and the strength of the phase domain energy compared to the bending energy. Using a pre-segregated vesicle, three dynamics are observed: stationary phase, phase-treading, and a new dynamic called vertical banding. These regimes are very sensitive to the strength of the domain line energy, as the vertical banding regime is not observed when the line energy is larger than the bending energy. The findings demonstrate that a complete understanding of multicomponent vesicle dynamics requires that the full three-dimensional system be modeled, and show the complexity obtained when considering heterogeneous material properties.
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Affiliation(s)
- Prerna Gera
- Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY 14260-4400, USA.
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Peyret A, Zhao H, Lecommandoux S. Preparation and Properties of Asymmetric Synthetic Membranes Based on Lipid and Polymer Self-Assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:3376-3385. [PMID: 29486556 DOI: 10.1021/acs.langmuir.7b04233] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cell membrane asymmetry is a common structural feature of all biological cells. Researchers have tried for decades to better study its formation and its function in membrane-regulated phenomena. In particular, there has been increasing interest in developing synthetic asymmetric membrane models in the laboratory, with the aim of studying basic physical chemistry properties that may be correlated to a relevant biological function. The present article aims to summarize the main presented approaches to prepare asymmetric membranes, which are most often made from lipids, polymers, or a combination of both.
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Affiliation(s)
- Ariane Peyret
- Laboratoire de Chimie des Polymères Organiques, LCPO, Université de Bordeaux, CNRS, Bordeaux INP, UMR 5629 , 16 Avenue Pey Berland F-33600 Pessac , France
| | - Hang Zhao
- Laboratoire de Chimie des Polymères Organiques, LCPO, Université de Bordeaux, CNRS, Bordeaux INP, UMR 5629 , 16 Avenue Pey Berland F-33600 Pessac , France
| | - Sébastien Lecommandoux
- Laboratoire de Chimie des Polymères Organiques, LCPO, Université de Bordeaux, CNRS, Bordeaux INP, UMR 5629 , 16 Avenue Pey Berland F-33600 Pessac , France
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46
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Heberle FA, Pabst G. Complex biomembrane mimetics on the sub-nanometer scale. Biophys Rev 2017; 9:353-373. [PMID: 28717925 PMCID: PMC5578918 DOI: 10.1007/s12551-017-0275-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 06/26/2017] [Indexed: 12/12/2022] Open
Abstract
Biomimetic lipid vesicles are indispensable tools for gaining insight into the biophysics of cell physiology on the molecular level. The level of complexity of these model systems has steadily increased, and now spans from domain-forming lipid mixtures to asymmetric lipid bilayers. Here, we review recent progress in the development and application of elastic neutron and X-ray scattering techniques for studying these systems in situ and under physiologically relevant conditions on the nanometer to sub-nanometer length scales. In particular, we focus on: (1) structural details of coexisting liquid-ordered and liquid-disordered domains, including their thickness and lipid packing mismatch as a function of a size transition from nanoscopic to macroscopic domains; (2) membrane-mediated protein partitioning into lipid domains; (3) the role of the aqueous medium in tuning interactions between membranes and domains; and (4) leaflet-specific structure in asymmetric bilayers and passive lipid flip-flop.
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Affiliation(s)
- Frederick A Heberle
- The Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA.,Joint Institute for Biological Sciences and Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz, 8010, Graz, Austria. .,BioTechMed-Graz, 8010, Graz, Austria.
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Salehi-Reyhani A, Ces O, Elani Y. Artificial cell mimics as simplified models for the study of cell biology. Exp Biol Med (Maywood) 2017; 242:1309-1317. [PMID: 28580796 PMCID: PMC5528198 DOI: 10.1177/1535370217711441] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Living cells are hugely complex chemical systems composed of a milieu of distinct chemical species (including DNA, proteins, lipids, and metabolites) interconnected with one another through a vast web of interactions: this complexity renders the study of cell biology in a quantitative and systematic manner a difficult task. There has been an increasing drive towards the utilization of artificial cells as cell mimics to alleviate this, a development that has been aided by recent advances in artificial cell construction. Cell mimics are simplified cell-like structures, composed from the bottom-up with precisely defined and tunable compositions. They allow specific facets of cell biology to be studied in isolation, in a simplified environment where control of variables can be achieved without interference from a living and responsive cell. This mini-review outlines the core principles of this approach and surveys recent key investigations that use cell mimics to address a wide range of biological questions. It will also place the field in the context of emerging trends, discuss the associated limitations, and outline future directions of the field. Impact statement Recent years have seen an increasing drive to construct cell mimics and use them as simplified experimental models to replicate and understand biological phenomena in a well-defined and controlled system. By summarizing the advances in this burgeoning field, and using case studies as a basis for discussion on the limitations and future directions of this approach, it is hoped that this minireview will spur others in the experimental biology community to use artificial cells as simplified models with which to probe biological systems.
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Affiliation(s)
| | - Oscar Ces
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
| | - Yuval Elani
- Department of Chemistry, Imperial College London, London SW7 2AZ, UK
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Geng Z, Han Y, Jiang W. Structural transformation of vesicles formed by a polystyrene-b-poly(acrylic acid)/polystyrene-b-poly(4-vinyl pyridine) mixture: from symmetric to asymmetric membranes. SOFT MATTER 2017; 13:2634-2642. [PMID: 28327712 DOI: 10.1039/c7sm00255f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Asymmetric vesicles with different inner and outer corona compositions are applicable in microreactors, drug delivery, and biomimics because of their unique functions in membrane permeability and protein localization. In this study, we develop a novel approach to construct asymmetric vesicles and demonstrate the first structural transformation of polymeric vesicles from symmetric to asymmetric membranes. Experimental results and Monte Carlo simulation results clearly reveal that increased intercorona repulsion and enhanced hydrophobic chain mobility are essential to realize this transformation. Moreover, similar transformation processes are observed where either HCl or NaOH is added to change the intercorona interaction. This finding indicates that the observed structural transformation is dominated by physical interactions rather than chemical environment. The constructed asymmetric vesicles can be selectively decorated with gold nanoparticles on the outer corona. This study introduces a novel approach to prepare asymmetric vesicles and provides insights into the mechanism underlying the structural transformation of polymeric vesicles from symmetric to asymmetric membranes.
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Affiliation(s)
- Zhen Geng
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China. and University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yuanyuan Han
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
| | - Wei Jiang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
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St. Clair JR, Wang Q, Li G, London E. Preparation and Physical Properties of Asymmetric Model Membrane Vesicles. SPRINGER SERIES IN BIOPHYSICS 2017. [DOI: 10.1007/978-981-10-6244-5_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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