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Griffo A, Sparn C, Lolicato F, Nolle F, Khangholi N, Seemann R, Fleury JB, Brinkmann M, Nickel W, Hähl H. Mechanics of biomimetic free-standing lipid membranes: insights into the elasticity of complex lipid compositions. RSC Adv 2024; 14:13044-13052. [PMID: 38655466 PMCID: PMC11034475 DOI: 10.1039/d4ra00738g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/08/2024] [Indexed: 04/26/2024] Open
Abstract
The creation of free-standing lipid membranes has been so far of remarkable interest to investigate processes occurring in the cell membrane since its unsupported part enables studies in which it is important to maintain cell-like physicochemical properties of the lipid bilayer, that nonetheless depend on its molecular composition. In this study, we prepare pore-spanning membranes that mimic the composition of plasma membranes and perform force spectroscopy indentation measurements to unravel mechanistic insights depending on lipid composition. We show that this approach is highly effective for studying the mechanical properties of such membranes. Furthermore, we identify a direct influence of cholesterol and sphingomyelin on the elasticity of the bilayer and adhesion between the two leaflets. Eventually, we explore the possibilities of imaging in the unsupported membrane regions. For this purpose, we investigate the adsorption and movement of a peripheral protein, the fibroblast growth factor 2, on the complex membrane.
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Affiliation(s)
- Alessandra Griffo
- Center for Biophysics, Experimental Physics, Saarland University Saarbrücken Germany
- Department of Experimental Physics, Saarland University Saarbrücken Germany
- Biophysical Engineering Group, Max Planck Institute for Medical Research Heidelberg Germany
| | - Carola Sparn
- Heidelberg University Biochemistry Center Heidelberg Germany
| | - Fabio Lolicato
- Heidelberg University Biochemistry Center Heidelberg Germany
| | - Friederike Nolle
- Center for Biophysics, Experimental Physics, Saarland University Saarbrücken Germany
- Department of Experimental Physics, Saarland University Saarbrücken Germany
| | - Navid Khangholi
- Center for Biophysics, Experimental Physics, Saarland University Saarbrücken Germany
- Department of Experimental Physics, Saarland University Saarbrücken Germany
| | - Ralf Seemann
- Center for Biophysics, Experimental Physics, Saarland University Saarbrücken Germany
| | - Jean-Baptiste Fleury
- Center for Biophysics, Experimental Physics, Saarland University Saarbrücken Germany
- Department of Experimental Physics, Saarland University Saarbrücken Germany
| | - Martin Brinkmann
- Department of Experimental Physics, Saarland University Saarbrücken Germany
| | - Walter Nickel
- Heidelberg University Biochemistry Center Heidelberg Germany
| | - Hendrik Hähl
- Center for Biophysics, Experimental Physics, Saarland University Saarbrücken Germany
- Department of Experimental Physics, Saarland University Saarbrücken Germany
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2
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Bernard C, Carotenuto AR, Pugno NM, Fraldi M, Deseri L. Modelling lipid rafts formation through chemo-mechanical interplay triggered by receptor-ligand binding. Biomech Model Mechanobiol 2024; 23:485-505. [PMID: 38060155 PMCID: PMC10963483 DOI: 10.1007/s10237-023-01787-2] [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: 07/28/2023] [Accepted: 10/21/2023] [Indexed: 12/08/2023]
Abstract
Cell membranes, mediator of many biological mechanisms from adhesion and metabolism up to mutation and infection, are highly dynamic and heterogeneous environments exhibiting a strong coupling between biochemical events and structural re-organisation. This involves conformational changes induced, at lower scales, by lipid order transitions and by the micro-mechanical interplay of lipids with transmembrane proteins and molecular diffusion. Particular attention is focused on lipid rafts, ordered lipid microdomains rich of signalling proteins, that co-localise to enhance substance trafficking and activate different intracellular biochemical pathways. In this framework, the theoretical modelling of the dynamic clustering of lipid rafts implies a full multiphysics coupling between the kinetics of phase changes and the mechanical work performed by transmembrane proteins on lipids, involving the bilayer elasticity. This mechanism produces complex interspecific dynamics in which membrane stresses and chemical potentials do compete by determining different morphological arrangements, alteration in diffusive walkways and coalescence phenomena, with a consequent influence on both signalling potential and intracellular processes. Therefore, after identifying the leading chemo-mechanical interactions, the present work investigates from a modelling perspective the spatio-temporal evolution of raft domains to theoretically explain co-localisation and synergy between proteins' activation and raft formation, by coupling diffusive and mechanical phenomena to observe different morphological patterns and clustering of ordered lipids. This could help to gain new insights into the remodelling of cell membranes and could potentially suggest mechanically based strategies to control their selectivity, by orienting intracellular functions and mechanotransduction.
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Affiliation(s)
- Chiara Bernard
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
| | - Angelo Rosario Carotenuto
- Department of Structures for Engineering and Architecture, University of Naples "Federico II", Naples, Italy
- Laboratory of Integrated Mechanics and Imaging for Testing and Simulation (LIMITS), University of Naples "Federico II", Naples, Italy
| | - Nicola Maria Pugno
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy
- Laboratory for Bioinspired, Bionic, Nano, Meta Materials and Mechanics, University of Trento, Trento, Italy
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Massimiliano Fraldi
- Department of Structures for Engineering and Architecture, University of Naples "Federico II", Naples, Italy
- Laboratory of Integrated Mechanics and Imaging for Testing and Simulation (LIMITS), University of Naples "Federico II", Naples, Italy
- Département de Physique, LPENS, École Normale Supérieure-PSL, Paris, France
| | - Luca Deseri
- Department of Civil, Environmental and Mechanical Engineering, University of Trento, Trento, Italy.
- Department of Mechanical Engineering and Material Sciences, MEMS-SSoE, University of Pittsburgh, Pittsburgh, USA.
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, USA.
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, USA.
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3
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Socrier L, Steinem C. Pore-spanning membranes as a tool to investigate lateral lipid membrane heterogeneity. Methods Enzymol 2024; 700:455-483. [PMID: 38971610 DOI: 10.1016/bs.mie.2024.02.009] [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] [Indexed: 07/08/2024]
Abstract
Over the years, it has become more and more obvious that lipid membranes show a very complex behavior. This behavior arises in part from the large number of different kinds of lipids and proteins and how they dynamically interact with each other. In vitro studies using artificial membrane systems have shed light on the heterogeneity based on lipid-lipid interactions in multicomponent bilayer mixtures. Inspired by the raft hypothesis, the coexistence of liquid-disordered (ld) and liquid-ordered (lo) phases has drawn much attention. It was shown that ternary lipid mixtures containing low- and high-melting temperature lipids and cholesterol can phase separate into a lo phase enriched in the high-melting lipids and cholesterol and a ld phase enriched in the low-melting lipids. Depending on the model membrane system under investigation, different domain sizes, shapes, and mobilities have been found. Here, we describe how to generate phase-separated lo/ld phases in model membrane systems termed pore-spanning membranes (PSMs). These PSMs are prepared on porous silicon substrates with pore sizes in the micrometer regime. A proper functionalization of the top surface of the substrates is required to achieve the spreading of giant unilamellar vesicles (GUVs) to obtain PSMs. Starting with lo/ld phase-separated GUVs lead to membrane heterogeneities in the PSMs. Depending on the functionalization strategy of the top surface of the silicon substrate, different membrane heterogeneities are observed in the PSMs employing fluorescence microscopy. A quantitative analysis of the heterogeneity as well as the dynamics of the lipid domains is described.
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Affiliation(s)
- Larissa Socrier
- Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany
| | - Claudia Steinem
- Max-Planck-Institute for Dynamics and Self-Organization, Göttingen, Germany; Institute of Organic and Biomolecular Chemistry, Georg-August Universität, Göttingen, Germany.
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4
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Chen T, Karedla N, Enderlein J. Measuring sub-nanometer undulations at microsecond temporal resolution with metal- and graphene-induced energy transfer spectroscopy. Nat Commun 2024; 15:1789. [PMID: 38413608 PMCID: PMC10899616 DOI: 10.1038/s41467-024-45822-x] [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: 06/01/2023] [Accepted: 02/01/2024] [Indexed: 02/29/2024] Open
Abstract
Out-of-plane fluctuations, also known as stochastic displacements, of biological membranes play a crucial role in regulating many essential life processes within cells and organelles. Despite the availability of various methods for quantifying membrane dynamics, accurately quantifying complex membrane systems with rapid and tiny fluctuations, such as mitochondria, remains a challenge. In this work, we present a methodology that combines metal/graphene-induced energy transfer (MIET/GIET) with fluorescence correlation spectroscopy (FCS) to quantify out-of-plane fluctuations of membranes with simultaneous spatiotemporal resolution of approximately one nanometer and one microsecond. To validate the technique and spatiotemporal resolution, we measure bending undulations of model membranes. Furthermore, we demonstrate the versatility and applicability of MIET/GIET-FCS for studying diverse membrane systems, including the widely studied fluctuating membrane system of human red blood cells, as well as two unexplored membrane systems with tiny fluctuations, a pore-spanning membrane, and mitochondrial inner/outer membranes.
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Affiliation(s)
- Tao Chen
- Third Institute of Physics - Biophysics, Georg August University, Friedrich-Hund-Platz 1, Göttingen, 37077, Germany
| | - Narain Karedla
- The Rosalind Franklin Institute, Harwell Campus, Didcot, OX11 OFA, UK
- Kennedy Institute of Rheumatology, University of Oxford, Roosevelt Drive, Oxford, OX3 7LF, UK
| | - Jörg Enderlein
- Third Institute of Physics - Biophysics, Georg August University, Friedrich-Hund-Platz 1, Göttingen, 37077, Germany.
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), Universitätsmedizin Göttingen, Robert-Koch-Str. 40, Göttingen, 37075, Germany.
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5
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Zhang L, Liu N, Wang X. Probe the nanoparticle-nucleus interaction via coarse-grained molecular model. Phys Chem Chem Phys 2023; 25:30319-30329. [PMID: 37908190 DOI: 10.1039/d3cp02981f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The present study reports on a computational model that systematically evaluates the effect of physical factors, including size, surface modification, and rigidity, on the nuclear uptake of nanoparticles (NPs). The NP-nucleus interaction is a crucial factor in biomedical applications such as drug delivery and cellular imaging. While experimental studies have provided evidence for the influence of size, shape, and surface modification on nuclear uptake, theoretical investigations on how these physical factors affect the entrance of NPs through the nuclear pore are lacking. Our results demonstrate that larger NPs require a higher amount of energy to enter the nucleus compared to smaller NPs. This highlights the importance of size as a critical factor in NP design for nuclear uptake. Additionally, surface modification of NPs can impact the nuclear uptake pathway, indicating the potential for tailored NP design for specific applications. Notably, our findings also reveal that the rigidity of NPs has a significant effect on the transport process. The interplay between physicochemical properties and nuclear pore is found to determine nuclear uptake efficiency. Taken together, our study provides new insights into the design of NPs for precise and controllable NP-nucleus interaction, with potential implications for the development of efficient and targeted drug delivery systems and imaging agents.
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Affiliation(s)
- Liuyang Zhang
- State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, People's Republic of China
| | - Ning Liu
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092, P. R. China.
| | - Xianqiao Wang
- College of Engineering, University of Georgia, Athens, GA 30602, USA
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6
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Xin Y, Li K, Huang M, Liang C, Siemann D, Wu L, Tan Y, Tang X. Biophysics in tumor growth and progression: from single mechano-sensitive molecules to mechanomedicine. Oncogene 2023; 42:3457-3490. [PMID: 37864030 PMCID: PMC10656290 DOI: 10.1038/s41388-023-02844-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 09/08/2023] [Accepted: 09/15/2023] [Indexed: 10/22/2023]
Abstract
Evidence from physical sciences in oncology increasingly suggests that the interplay between the biophysical tumor microenvironment and genetic regulation has significant impact on tumor progression. Especially, tumor cells and the associated stromal cells not only alter their own cytoskeleton and physical properties but also remodel the microenvironment with anomalous physical properties. Together, these altered mechano-omics of tumor tissues and their constituents fundamentally shift the mechanotransduction paradigms in tumorous and stromal cells and activate oncogenic signaling within the neoplastic niche to facilitate tumor progression. However, current findings on tumor biophysics are limited, scattered, and often contradictory in multiple contexts. Systematic understanding of how biophysical cues influence tumor pathophysiology is still lacking. This review discusses recent different schools of findings in tumor biophysics that have arisen from multi-scale mechanobiology and the cutting-edge technologies. These findings range from the molecular and cellular to the whole tissue level and feature functional crosstalk between mechanotransduction and oncogenic signaling. We highlight the potential of these anomalous physical alterations as new therapeutic targets for cancer mechanomedicine. This framework reconciles opposing opinions in the field, proposes new directions for future cancer research, and conceptualizes novel mechanomedicine landscape to overcome the inherent shortcomings of conventional cancer diagnosis and therapies.
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Grants
- R35 GM150812 NIGMS NIH HHS
- This work was financially supported by National Natural Science Foundation of China (Project no. 11972316, Y.T.), Shenzhen Science and Technology Innovation Commission (Project no. JCYJ20200109142001798, SGDX2020110309520303, and JCYJ20220531091002006, Y.T.), General Research Fund of Hong Kong Research Grant Council (PolyU 15214320, Y. T.), Health and Medical Research Fund (HMRF18191421, Y.T.), Hong Kong Polytechnic University (1-CD75, 1-ZE2M, and 1-ZVY1, Y.T.), the Cancer Pilot Research Award from UF Health Cancer Center (X. T.), the National Institute of General Medical Sciences of the National Institutes of Health under award number R35GM150812 (X. T.), the National Science Foundation under grant number 2308574 (X. T.), the Air Force Office of Scientific Research under award number FA9550-23-1-0393 (X. T.), the University Scholar Program (X. T.), UF Research Opportunity Seed Fund (X. T.), the Gatorade Award (X. T.), and the National Science Foundation REU Site at UF: Engineering for Healthcare (Douglas Spearot and Malisa Sarntinoranont). We are deeply grateful for the insightful discussions with and generous support from all members of Tang (UF)’s and Tan (PolyU)’s laboratories and all staff members of the MAE/BME/ECE/Health Cancer Center at UF and BME at PolyU.
- National Natural Science Foundation of China (National Science Foundation of China)
- Shenzhen Science and Technology Innovation Commission
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Affiliation(s)
- Ying Xin
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
| | - Keming Li
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China
| | - Miao Huang
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, USA
| | - Chenyu Liang
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, USA
| | - Dietmar Siemann
- UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Lizi Wu
- UF Health Cancer Center, University of Florida, Gainesville, FL, USA
| | - Youhua Tan
- The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China.
- Department of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, China.
- Research Institute of Smart Ageing, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Xin Tang
- Department of Mechanical and Aerospace Engineering, Herbert Wertheim College of Engineering, University of Florida, Gainesville, FL, USA.
- UF Health Cancer Center, University of Florida, Gainesville, FL, USA.
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA.
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7
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Carmesin CF, Port F, Böhringer S, Gottschalk KE, Rasche V, Jansen S. Ageing-induced shrinkage of intervessel pit membranes in xylem of Clematis vitalba modifies its mechanical properties as revealed by atomic force microscopy. FRONTIERS IN PLANT SCIENCE 2023; 14:1002711. [PMID: 36755701 PMCID: PMC9899931 DOI: 10.3389/fpls.2023.1002711] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/05/2023] [Indexed: 06/18/2023]
Abstract
Bordered pit membranes of angiosperm xylem are anisotropic, mesoporous media between neighbouring conduits, with a key role in long distance water transport. Yet, their mechanical properties are poorly understood. Here, we aim to quantify the stiffness of intervessel pit membranes over various growing seasons. By applying an AFM-based indentation technique "Quantitative Imaging" we measured the effective elastic modulus (E effective) of intervessel pit membranes of Clematis vitalba in dependence of size, age, and hydration state. The indentation-deformation behaviour was analysed with a non-linear membrane model, and paired with magnetic resonance imaging to visualise sap-filled and embolised vessels, while geometrical data of bordered pits were obtained using electron microscopy. E effective was transformed to the geometrically independent apparent elastic modulus E apparent and to aspiration pressure P b. The material stiffness (E apparent) of fresh pit membranes was with 57 MPa considerably lower than previously suggested. The estimated pressure for pit membrane aspiration was 2.20+28 MPa. Pit membranes from older growth rings were shrunken, had a higher material stiffness and a lower aspiration pressure than current year ones, suggesting an irreversible, mechanical ageing process. This study provides an experimental-stiffness analysis of hydrated intervessel pit membranes in their native state. The estimated aspiration pressure suggests that membranes are not deflected under normal field conditions. Although absolute values should be interpreted carefully, our data suggest that pit membrane shrinkage implies increasing material stiffness, and highlight the dynamic changes of pit membrane mechanics and their complex, functional behaviour for fluid transport.
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Affiliation(s)
- Cora F. Carmesin
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, Germany
| | - Fabian Port
- Institute of Experimental Physics, Ulm University, Albert Einstein Allee 45, Ulm, Germany
| | - Samuel Böhringer
- Institut für Quantenphysik and Center for Integrated Quantum Science and Technology, Universität Ulm, Albert-Einstein-Allee 11, Ulm, Germany
| | | | - Volker Rasche
- Core Facility Small Animal Imaging, Medical Faculty, Ulm University, Ulm, Germany
- Department of Internal Medicine II, Ulm University, Albert Einstein Allee 45, Ulm, Germany
| | - Steven Jansen
- Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, Ulm, Germany
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Baek JM, Jung WH, Yu ES, Ahn DJ, Ryu YS. In Vitro Membrane Platform for the Visualization of Water Impermeability across the Liquid-Ordered Phase under Hypertonic Conditions. J Am Chem Soc 2022; 144:21887-21896. [PMID: 36367984 DOI: 10.1021/jacs.2c06626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Passive water penetration across the cell membrane by osmotic diffusion is essential for the homeostasis of cell volume, in addition to the protein-assisted active transportation of water. Since membrane components can regulate water permeability, controlling compositional variation during the volume regulatory process is a prerequisite for investigating the underlying mechanisms of water permeation and related membrane dynamics. However, the lack of a viable in vitro membrane platform in hypertonic solutions impedes advanced knowledge of cell volume regulation processes, especially cholesterol-enriched lipid domains called lipid rafts. By reconstituting the liquid-ordered (Lo) domain as a likeness of lipid rafts, we verified suppressed water permeation across the Lo domains, which had yet to be confirmed with experimental demonstrations despite a simulation approach. With the help of direct transfer of the Lo domains from vesicles to supported lipid membranes, the biological roles of lipid composition in suppressed water translocation were experimentally confirmed. Additionally, the improvement in membrane stability under hypertonic conditions was demonstrated based on molecular dynamics simulations.
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Affiliation(s)
- Ji Min Baek
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.,Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Woo Hyuk Jung
- Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Eui-Sang Yu
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Dong June Ahn
- Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Republic of Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea
| | - Yong-Sang Ryu
- Brain Science Institute, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Republic of Korea
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9
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Tan Y, Hu X, Hou Y, Chu Z. Emerging Diamond Quantum Sensing in Bio-Membranes. MEMBRANES 2022; 12:957. [PMID: 36295716 PMCID: PMC9609316 DOI: 10.3390/membranes12100957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Bio-membranes exhibit complex but unique mechanical properties as communicative regulators in various physiological and pathological processes. Exposed to a dynamic micro-environment, bio-membranes can be seen as an intricate and delicate system. The systematical modeling and detection of their local physical properties are often difficult to achieve, both quantitatively and precisely. The recent emerging diamonds hosting quantum defects (i.e., nitrogen-vacancy (NV) center) demonstrate intriguing optical and spin properties, together with their outstanding photostability and biocompatibility, rendering them ideal candidates for biological applications. Notably, the extraordinary spin-based sensing enable the measurements of localized nanoscale physical quantities such as magnetic fields, electrical fields, temperature, and strain. These nanoscale signals can be optically read out precisely by simple optical microscopy systems. Given these exclusive properties, NV-center-based quantum sensors can be widely applied in exploring bio-membrane-related features and the communicative chemical reaction processes. This review mainly focuses on NV-based quantum sensing in bio-membrane fields. The attempts of applying NV-based quantum sensors in bio-membranes to investigate diverse physical and chemical events such as membrane elasticity, phase change, nanoscale bio-physical signals, and free radical formation are fully overviewed. We also discuss the challenges and future directions of this novel technology to be utilized in bio-membranes.
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Affiliation(s)
- Yayin Tan
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - Xinhao Hu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - Yong Hou
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
| | - Zhiqin Chu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong 999077, China
- Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong 999077, China
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10
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Muhammed E, Cooper J, Devito D, Mushi R, del Pilar Aguinaga M, Erenso D, Crogman H. Elastic property of sickle cell anemia and sickle cell trait red blood cells. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210188R. [PMID: 34590447 PMCID: PMC8479689 DOI: 10.1117/1.jbo.26.9.096502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/02/2021] [Indexed: 05/14/2023]
Abstract
SIGNIFICANCE We introduce a model for better calibration of the trapping force using an equal but oppositely directed drag force acting on a trapped red blood cell (RBC). We demonstrate this approach by studying RBCs' elastic properties from deidentified sickle cell anemia (SCA) and sickle cell trait (SCT) blood samples. AIM A laser trapping (LT) force was formulated and analytically calculated in a cylindrical model. Using this trapping force relative percent difference, the maximum (longitudinal) and minimum (transverse) radius rate and stiffness were used to study the elasticity. APPROACH The elastic property of SCA and SCT RBCs was analyzed using LT technique with computer controlled piezo-driven stage, in order to trap and stretch the RBCs. RESULTS For all parameters, the results show that the SCT RBC samples have higher elastic property than the SCA RBCs. The higher rigidity in the SCA cell may be due to the lipid composition of the membrane, which was affected by the cholesterol concentration. CONCLUSIONS By developing a theoretical model for different trapping forces, we have also studied the elasticity of RBCs in SCT (with hemoglobin type HbAS) and in SCA (with hemoglobin type HbSS). The results for the quantities describing the elasticity of the cells consistently showed that the RBCs in the SCT display lower rigidity and higher deformability than the RBCs with SCA.
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Affiliation(s)
- Endris Muhammed
- Addis Ababa University, Department of Physics, Addis Ababa, Ethiopia
| | - James Cooper
- Middle Tennessee State University, Department of Physics, Murfreesboro, Tennessee, United States
| | - Daniel Devito
- Middle Tennessee State University, Department of Physics, Murfreesboro, Tennessee, United States
| | - Robert Mushi
- Meharry Medical College, Meharry Sickle Cell Center, Department of Internal Medicine, Nashville, Tennessee, United States
| | - Maria del Pilar Aguinaga
- Meharry Medical College, Meharry Sickle Cell Center, Department of Internal Medicine, Nashville, Tennessee, United States
- Meharry Medical College, Department of Obstetrics and Gynecology, Nashville, Tennessee, United States
| | - Daniel Erenso
- Middle Tennessee State University, Department of Physics, Murfreesboro, Tennessee, United States
| | - Horace Crogman
- California State University Dominguez Hills, Department of Physics, Carson, California, United States
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11
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Diederichs T, Tampé R. Membrane-Suspended Nanopores in Microchip Arrays for Stochastic Transport Recording and Sensing. FRONTIERS IN NANOTECHNOLOGY 2021. [DOI: 10.3389/fnano.2021.703673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The transport of nutrients, xenobiotics, and signaling molecules across biological membranes is essential for life. As gatekeepers of cells, membrane proteins and nanopores are key targets in pharmaceutical research and industry. Multiple techniques help in elucidating, utilizing, or mimicking the function of biological membrane-embedded nanodevices. In particular, the use of DNA origami to construct simple nanopores based on the predictable folding of nucleotides provides a promising direction for innovative sensing and sequencing approaches. Knowledge of translocation characteristics is crucial to link structural design with function. Here, we summarize recent developments and compare features of membrane-embedded nanopores with solid-state analogues. We also describe how their translocation properties are characterized by microchip systems. The recently developed silicon chips, comprising solid-state nanopores of 80 nm connecting femtoliter cavities in combination with vesicle spreading and formation of nanopore-suspended membranes, will pave the way to characterize translocation properties of nanopores and membrane proteins in high-throughput and at single-transporter resolution.
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12
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Mühlenbrock P, Sari M, Steinem C. In vitro single vesicle fusion assays based on pore-spanning membranes: merits and drawbacks. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:239-252. [PMID: 33320298 PMCID: PMC8071798 DOI: 10.1007/s00249-020-01479-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 12/22/2022]
Abstract
Neuronal fusion mediated by soluble N-ethylmaleimide-sensitive-factor attachment protein receptors (SNAREs) is a fundamental cellular process by which two initially distinct membranes merge resulting in one interconnected structure to release neurotransmitters into the presynaptic cleft. To get access to the different stages of the fusion process, several in vitro assays have been developed. In this review, we provide a short overview of the current in vitro single vesicle fusion assays. Among those assays, we developed a single vesicle assay based on pore-spanning membranes (PSMs) on micrometre-sized pores in silicon, which might overcome some of the drawbacks associated with the other membrane architectures used for investigating fusion processes. Prepared by spreading of giant unilamellar vesicles with reconstituted t-SNAREs, PSMs provide an alternative tool to supported lipid bilayers to measure single vesicle fusion events by means of fluorescence microscopy. Here, we discuss the diffusive behaviour of the reconstituted membrane components as well as that of the fusing synthetic vesicles with reconstituted synaptobrevin 2 (v-SNARE). We compare our results with those obtained if the synthetic vesicles are replaced by natural chromaffin granules under otherwise identical conditions. The fusion efficiency as well as the different fusion states observable in this assay by means of both lipid mixing and content release are illuminated.
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Affiliation(s)
- Peter Mühlenbrock
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Tammannstr. 2, 37077, Göttingen, Germany
| | - Merve Sari
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Tammannstr. 2, 37077, Göttingen, Germany
| | - Claudia Steinem
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Tammannstr. 2, 37077, Göttingen, Germany.
- Max-Planck-Institute for Dynamics and Self Organization, Am Faßberg 17, 37077, Göttingen, Germany.
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13
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Omidvar R, Ayala YA, Brandel A, Hasenclever L, Helmstädter M, Rohrbach A, Römer W, Madl J. Quantification of nanoscale forces in lectin-mediated bacterial attachment and uptake into giant liposomes. NANOSCALE 2021; 13:4016-4028. [PMID: 33503085 DOI: 10.1039/d0nr07726g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Interactions of the bacterial lectin LecA with the host cells glycosphingolipid Gb3 have been shown to be crucial for the cellular uptake of the bacterium Pseudomonas aeruginosa. LecA-induced Gb3 clustering, referred to as lipid zipper mechanism, leads to full membrane engulfment of the bacterium. Here, we aim for a nanoscale force characterization of this mechanism using two complementary force probing techniques, atomic force microscopy (AFM) and optical tweezers (OT). The LecA-Gb3 interactions are reconstituted using giant unilamellar vesicles (GUVs), a well-controlled minimal system mimicking the plasma membrane and nanoscale forces between either bacteria (PAO1 wild-type and LecA-deletion mutant strains) or LecA-coated probes (as minimal, synthetic bacterial model) and vesicles are measured. LecA-Gb3 interactions strengthen the bacterial attachment to the membrane (1.5-8-fold) depending on the membrane tension and the applied technique. Moreover, significantly less energy (reduction up to 80%) is required for the full uptake of LecA-coated beads into Gb3-functionalized vesicles. This quantitative approach highlights that lectin-glycolipid interactions provide adequate forces and energies to drive bacterial attachment and uptake.
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Affiliation(s)
- Ramin Omidvar
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany. and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany and Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
| | - Yareni A Ayala
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany.
| | - Annette Brandel
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany. and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
| | - Lukas Hasenclever
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany. and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
| | - Martin Helmstädter
- Renal Division, Department of Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany
| | - Alexander Rohrbach
- Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany.
| | - Winfried Römer
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany. and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany and Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
| | - Josef Madl
- Faculty of Biology, University of Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany. and Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany and Freiburg Center for Interactive Materials and Bioinspired Technologies (FIT), University of Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
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14
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Abstract
Cellular membranes are anything but flat structures. They display a wide variety of complex and beautiful shapes, most of which have evolved for a particular physiological reason and are adapted to accommodate certain cellular demands. In membrane trafficking events, the dynamic remodelling of cellular membranes is apparent. In clathrin-mediated endocytosis for example, the plasma membrane undergoes heavy deformation to generate and internalize a highly curved clathrin-coated vesicle. This process has become a model system to study proteins with the ability to sense and induce membrane curvature and over the last two decades numerous membrane remodelling molecules and molecular mechanisms have been identified in this process. In this review, we discuss the interaction of epsin1 ENTH domain with membranes, which is one of the best-studied examples of a peripheral and transiently membrane bending protein important for clathrin-mediated endocytosis.
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Affiliation(s)
- Claudia Steinem
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
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15
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Hammond K, Ryadnov MG, Hoogenboom BW. Atomic force microscopy to elucidate how peptides disrupt membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183447. [PMID: 32835656 DOI: 10.1016/j.bbamem.2020.183447] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/30/2020] [Accepted: 08/13/2020] [Indexed: 12/24/2022]
Abstract
Atomic force microscopy is an increasingly attractive tool to study how peptides disrupt membranes. Often performed on reconstituted lipid bilayers, it provides access to time and length scales that allow dynamic investigations with nanometre resolution. Over the last decade, AFM studies have enabled visualisation of membrane disruption mechanisms by antimicrobial or host defence peptides, including peptides that target malignant cells and biofilms. Moreover, the emergence of high-speed modalities of the technique broadens the scope of investigations to antimicrobial kinetics as well as the imaging of peptide action on live cells in real time. This review describes how methodological advances in AFM facilitate new insights into membrane disruption mechanisms.
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Affiliation(s)
- Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Physics & Astronomy, University College London, London WC1E 6BT, UK.
| | - Maxim G Ryadnov
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, UK; Department of Physics, King's College London, Strand Lane, London WC2R 2LS, UK.
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Physics & Astronomy, University College London, London WC1E 6BT, UK.
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16
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Saavedra V O, Fernandes TFD, Milhiet PE, Costa L. Compression, Rupture, and Puncture of Model Membranes at the Molecular Scale. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5709-5716. [PMID: 32427478 DOI: 10.1021/acs.langmuir.0c00247] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Elastic properties of biological membranes are involved in a large number of membrane functionalities and activities. Conventionally characterized in terms of Young's modulus, bending stiffness and stretching modulus, membrane mechanics can be assessed at high lateral resolution by means of atomic force microscopy (AFM). Here we show that the mechanical response of biomimetic model systems such as supported lipid bilayers (SLBs) is highly affected by the size of the AFM tip employed as a membrane indenter. Our study is focused on phase-separated fluid-gel lipid membranes at room temperature. In a small tip radius regime (≈ 2 nm) and in the case of fluid phase membranes, we show that the tip can penetrate through the membrane minimizing molecular vertical compression and in absence of molecular membrane rupture. In this case, AFM indentation experiments cannot assess the vertical membrane Young's modulus. In agreement with the data reported in the literature, in the case of larger indenters (>2 nm) SLBs can be compressed leading to an evaluation of Young's modulus and membrane maximal withstanding force before rupture. We show that such force increases with the indenter in agreement with the existing theoretical frame. Finally, we demonstrate that the latter has no influence on the number of molecules involved in the rupture process that is observed to be constant and rather dependent on the indenter chemical composition.
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Affiliation(s)
- Oscar Saavedra V
- Centre de Biochimie Structurale (CBS), CNRS, INSERM, Univ. Montpellier, 34090 Montpellier, France
| | - Thales F D Fernandes
- Centre de Biochimie Structurale (CBS), CNRS, INSERM, Univ. Montpellier, 34090 Montpellier, France
| | - Pierre-Emmanuel Milhiet
- Centre de Biochimie Structurale (CBS), CNRS, INSERM, Univ. Montpellier, 34090 Montpellier, France
| | - Luca Costa
- Centre de Biochimie Structurale (CBS), CNRS, INSERM, Univ. Montpellier, 34090 Montpellier, France
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17
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Surface Sensitive Analysis Device using Model Membrane and Challenges for Biosensor-chip. BIOCHIP JOURNAL 2020. [DOI: 10.1007/s13206-019-4110-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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18
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Sun Y, Zang X, Sun Y, Wang L, Gao Z. Lipid membranes supported by planar porous substrates. Chem Phys Lipids 2020; 228:104893. [PMID: 32097619 DOI: 10.1016/j.chemphyslip.2020.104893] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 02/10/2020] [Indexed: 12/18/2022]
Abstract
Biological membranes play key roles in cell life, but their intrinsic complexity motivated the study and development of artificial lipid membranes with the primary aim to reconstitute and understand the natural functions in vitro. Porous-supported lipid membrane (pSLM) has emerged as a flexible platform for studying the surface chemistry of the cell due to their high stability and fluidity, and their ability to study the transmembrane process of the molecules. In this review, the pSLM, for the first time, to our knowledge, was divided into three types according to the way of the porous materials support the lipid membrane, containing the lipid membrane on the pores of the porous materials, the lipid membrane on both sides of the porous materials, the lipid membrane in the pores of the porous materials. All of these pSLMs were systematically elaborated from several aspects, including the substrates, formation, and characterization. Meanwhile, the advantages and disadvantages of each model membranes were summarized. Finally, suggestions for selecting appropriate pSLM and future directions in this area are discussed.
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Affiliation(s)
- Yanping Sun
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China; State Key Laboratory Breeding Base - Hebei Province Key Laboratory of Molecular Chemistry for Drugs, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology, Shijiazhuang, 050018, China
| | - Xianghuan Zang
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China
| | - Yongjun Sun
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology, Shijiazhuang, 050018, China
| | - Long Wang
- State Key Laboratory Breeding Base - Hebei Province Key Laboratory of Molecular Chemistry for Drugs, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Department of Family and Consumer Sciences, California State University, Long Beach, CA, 90840, USA.
| | - Zibin Gao
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, 050018, China; State Key Laboratory Breeding Base - Hebei Province Key Laboratory of Molecular Chemistry for Drugs, Hebei University of Science and Technology, Shijiazhuang, 050018, China; Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology, Shijiazhuang, 050018, China.
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19
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Shi X, Chen Y, Zhang X, Long X, Qian J. Biomass rhamnolipid modified poly(vinylidene fluoride) membrane with significantly improved surface hydrophilicity and enhanced antifouling performance. Chem Eng Sci 2020. [DOI: 10.1016/j.ces.2019.115330] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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20
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Sibold J, Tewaag VE, Vagedes T, Mey I, Steinem C. Phase separation in pore-spanning membranes induced by differences in surface adhesion. Phys Chem Chem Phys 2020; 22:9308-9315. [DOI: 10.1039/d0cp00335b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A porous scaffold providing different adhesion energies alters the behaviour of coexisting phases in lipid membranes considerably.
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Affiliation(s)
- Jeremias Sibold
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Vera E. Tewaag
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Thomas Vagedes
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Ingo Mey
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry
- University of Göttingen
- 37077 Göttingen
- Germany
- Max Planck Institute for Dynamics and Self-Organization
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21
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Saeedimasine M, Montanino A, Kleiven S, Villa A. Role of lipid composition on the structural and mechanical features of axonal membranes: a molecular simulation study. Sci Rep 2019; 9:8000. [PMID: 31142762 PMCID: PMC6541598 DOI: 10.1038/s41598-019-44318-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 05/13/2019] [Indexed: 12/16/2022] Open
Abstract
The integrity of cellular membranes is critical for the functionality of axons. Failure of the axonal membranes (plasma membrane and/or myelin sheath) can be the origin of neurological diseases. The two membranes differ in the content of sphingomyelin and galactosylceramide lipids. We investigate the relation between lipid content and bilayer structural-mechanical properties, to better understand the dependency of membrane properties on lipid composition. A sphingomyelin/phospholipid/cholesterol bilayer is used to mimic a plasma membrane and a galactosylceramide/phospholipid/cholesterol bilayer to mimic a myelin sheath. Molecular dynamics simulations are performed at atomistic and coarse-grained levels to characterize the bilayers at equilibrium and under deformation. For comparison, simulations of phospholipid and phospholipid/cholesterol bilayers are also performed. The results clearly show that the bilayer biomechanical and structural features depend on the lipid composition, independent of the molecular models. Both galactosylceramide or sphingomyelin lipids increase the order of aliphatic tails and resistance to water penetration. Having 30% galactosylceramide increases the bilayers stiffness. Galactosylceramide lipids pack together via sugar-sugar interactions and hydrogen-bond phosphocholine with a correlated increase of bilayer thickness. Our findings provide a molecular insight on role of lipid content in natural membranes.
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Affiliation(s)
- Marzieh Saeedimasine
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Annaclaudia Montanino
- Division of Neuronic Engineering, KTH-Royal Institute of Technology, Huddinge, Sweden
| | - Svein Kleiven
- Division of Neuronic Engineering, KTH-Royal Institute of Technology, Huddinge, Sweden
| | - Alessandra Villa
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden.
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22
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Spindler S, Sibold J, Gholami Mahmoodabadi R, Steinem C, Sandoghdar V. High-Speed Microscopy of Diffusion in Pore-Spanning Lipid Membranes. NANO LETTERS 2018; 18:5262-5271. [PMID: 30047737 DOI: 10.1021/acs.nanolett.8b02240] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Pore-spanning membranes (PSMs) provide a highly attractive model system for investigating fundamental processes in lipid bilayers. We measure and compare lipid diffusion in the supported and suspended regions of PSMs prepared on a microfabricated porous substrate. Although some properties of the suspended regions in PSMs have been characterized using fluorescence studies, it has not been possible to examine the mobility of membrane components on the supported membrane parts. Here, we resolve this issue by employing interferometric scattering microscopy (iSCAT). We study the location-dependent diffusion of DOPE 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) lipids (DOPE) labeled with gold nanoparticles in (1,2-dioleoyl-sn-glycero-3-phosphocholine) (DOPC) bilayers prepared on holey silicon nitride substrates that were either (i) oxygen-plasma-treated or (ii) functionalized with gold and 6-mercapto-1-hexanol. For both substrate treatments, diffusion in regions suspended on pores with diameters of 5 μm is found to be free. In the case of functionalization with gold and 6-mercapto-1-hexanol, similar diffusion coefficients are obtained for both the suspended and the supported regions, whereas for oxygen-plasma-treated surfaces, diffusion is almost 4 times slower in the supported parts of the membranes. We attribute this reduced diffusion on the supported parts in the case of oxygen-plasma-treated surfaces to larger membrane-substrate interactions, which lead to a higher membrane tension in the freestanding membrane parts. Furthermore, we find clear indications for a decrease of the diffusion constant in the freestanding regions away from the pore center. We provide a detailed characterization of the diffusion behavior in these membrane systems and discuss future directions.
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Affiliation(s)
- Susann Spindler
- Max Planck Institute for the Science of Light , Staudtstraße 2 , 91058 Erlangen , Germany
- Department of Physics , Friedrich Alexander University Erlangen-Nuremberg , Staudtstraße 5 , 91058 Erlangen , Germany
| | - Jeremias Sibold
- Institute for Organic and Biomolecular Chemistry , Tammannstraße 2 . 37077 Göttingen , Germany
| | - Reza Gholami Mahmoodabadi
- Max Planck Institute for the Science of Light , Staudtstraße 2 , 91058 Erlangen , Germany
- Department of Physics , Friedrich Alexander University Erlangen-Nuremberg , Staudtstraße 5 , 91058 Erlangen , Germany
| | - Claudia Steinem
- Institute for Organic and Biomolecular Chemistry , Tammannstraße 2 . 37077 Göttingen , Germany
- Max Planck Institute for Dynamics and Self-Organization , Am Faßberg 17 , 37077 Göttingen , Germany
| | - Vahid Sandoghdar
- Max Planck Institute for the Science of Light , Staudtstraße 2 , 91058 Erlangen , Germany
- Department of Physics , Friedrich Alexander University Erlangen-Nuremberg , Staudtstraße 5 , 91058 Erlangen , Germany
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23
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Gumí-Audenis B, Costa L, Ferrer-Tasies L, Ratera I, Ventosa N, Sanz F, Giannotti MI. Pulling lipid tubes from supported bilayers unveils the underlying substrate contribution to the membrane mechanics. NANOSCALE 2018; 10:14763-14770. [PMID: 30043793 DOI: 10.1039/c8nr03249a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cell processes like endocytosis, membrane resealing, signaling and transcription involve conformational changes which depend on the chemical composition and the physicochemical properties of the lipid membrane. The better understanding of the mechanical role of lipids in cell membrane force-triggered and sensing mechanisms has recently become the focus of attention. Different membrane models and experimental methodologies are commonly explored. While general approaches involve controlled vesicle deformation using micropipettes or optical tweezers, due to the local and dynamic nature of the membrane, high spatial resolution atomic force microscopy (AFM) has been widely used to study the mechanical compression and indentation of supported lipid bilayers (SLBs). However, the substrate contribution remains unkown. Here, we demonstrate how pulling lipid tubes with an AFM out of model SLBs can be used to assess the nanomechanics of SLBs through the evaluation of the tube growing force (Ftube), allowing for very local evaluation with high spatial and force resolution of the lipid membrane tension. We first validate this approach to determine the contribution of different phospholipids, by varying the membrane composition, in both one-component and phase-segregated membranes. Finally, we successfully assess the contribution of the underlying substrate to the membrane mechanics, demonstrating that SLB models may represent an intermediate scenario between a free membrane (blebs) and a cytoskeleton supported membrane.
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Affiliation(s)
- Berta Gumí-Audenis
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10-12, 08028 Barcelona, Spain.
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24
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Diederichs T, Nguyen QH, Urban M, Tampé R, Tornow M. Transparent Nanopore Cavity Arrays Enable Highly Parallelized Optical Studies of Single Membrane Proteins on Chip. NANO LETTERS 2018; 18:3901-3910. [PMID: 29741381 DOI: 10.1021/acs.nanolett.8b01252] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Membrane proteins involved in transport processes are key targets for pharmaceutical research and industry. Despite continuous improvements and new developments in the field of electrical readouts for the analysis of transport kinetics, a well-suited methodology for high-throughput characterization of single transporters with nonionic substrates and slow turnover rates is still lacking. Here, we report on a novel architecture of silicon chips with embedded nanopore microcavities, based on a silicon-on-insulator technology for high-throughput optical readouts. Arrays containing more than 14 000 inverted-pyramidal cavities of 50 femtoliter volumes and 80 nm circular pore openings were constructed via high-resolution electron-beam lithography in combination with reactive ion etching and anisotropic wet etching. These cavities feature both, an optically transparent bottom and top cap. Atomic force microscopy analysis reveals an overall extremely smooth chip surface, particularly in the vicinity of the nanopores, which exhibits well-defined edges. Our unprecedented transparent chip design provides parallel and independent fluorescent readout of both cavities and buffer reservoir for unbiased single-transporter recordings. Spreading of large unilamellar vesicles with efficiencies up to 96% created nanopore-supported lipid bilayers, which are stable for more than 1 day. A high lipid mobility in the supported membrane was determined by fluorescent recovery after photobleaching. Flux kinetics of α-hemolysin were characterized at single-pore resolution with a rate constant of 0.96 ± 0.06 × 10-3 s-1. Here, we deliver an ideal chip platform for pharmaceutical research, which features high parallelism and throughput, synergistically combined with single-transporter resolution.
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Affiliation(s)
- Tim Diederichs
- Institute of Biochemistry, Biocenter , Goethe University Frankfurt , Max-von-Laue-Str. 9 , 60438 Frankfurt/M. , Germany
| | - Quoc Hung Nguyen
- Molecular Electronics , Technical University of Munich , Theresienstrasse 90 , 80333 Munich , Germany
| | - Michael Urban
- Institute of Biochemistry, Biocenter , Goethe University Frankfurt , Max-von-Laue-Str. 9 , 60438 Frankfurt/M. , Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter , Goethe University Frankfurt , Max-von-Laue-Str. 9 , 60438 Frankfurt/M. , Germany
- Cluster of Excellence Frankfurt (CEF) Macromolecular Complexes ; Goethe University Frankfurt , Max-von-Laue-Strasse 9 , 60438 Frankfurt/M. , Germany
| | - Marc Tornow
- Molecular Electronics , Technical University of Munich , Theresienstrasse 90 , 80333 Munich , Germany
- Fraunhofer Research Institution for Microsystems and Solid State Technologies (EMFT) , Hansastrasse 27d , 80686 Munich , Germany
- Center for NanoScience (CeNS) , Ludwig-Maximilians-University , Geschwister-Scholl Platz 1 , 80539 Munich , Germany
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25
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Relat-Goberna J, Beedle AEM, Garcia-Manyes S. The Nanomechanics of Lipid Multibilayer Stacks Exhibits Complex Dynamics. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1700147. [PMID: 28503797 DOI: 10.1002/smll.201700147] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/17/2017] [Indexed: 06/07/2023]
Abstract
The nanomechanics of lipid membranes regulates a large number of cellular functions. However, the molecular mechanisms underlying the plastic rupture of individual bilayers remain elusive. This study uses force clamp spectroscopy to capture the force-dependent dynamics of membrane failure on a model diphytanoylphosphatidylcholine multilayer stack, which is devoid of surface effects. The obtained kinetic measurements demonstrate that the rupture of an individual lipid bilayer, occurring in the bilayer parallel plane, is a stochastic process that follows a log-normal distribution, compatible with a pore formation mechanism. Furthermore, the vertical individual force-clamp trajectories, occurring in the bilayer orthogonal bilayer plane, reveal that rupturing process occurs through distinct intermediate mechanical transition states that can be ascribed to the fine chemical composition of the hydrated phospholipid moiety. Altogether, these results provide a first description of unanticipated complexity in the energy landscape governing the mechanically induced bilayer rupture process.
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Affiliation(s)
- Josep Relat-Goberna
- Department of Physics and Randall Division of Cell and Molecular Biophysics, King's College London, Strand, London, WC2R 2LS, UK
| | - Amy E M Beedle
- Department of Physics and Randall Division of Cell and Molecular Biophysics, King's College London, Strand, London, WC2R 2LS, UK
| | - Sergi Garcia-Manyes
- Department of Physics and Randall Division of Cell and Molecular Biophysics, King's College London, Strand, London, WC2R 2LS, UK
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