1
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Moghimianavval H, Hsu YY, Groaz A, Liu AP. In Vitro Reconstitution Platforms of Mammalian Cell-Free Expressed Membrane Proteins. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2433:105-120. [PMID: 34985740 DOI: 10.1007/978-1-0716-1998-8_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Membrane proteins are essential components in cell membranes and enable cells to communicate with their outside environment and to carry out intracellular signaling. Functional reconstitution of complex membrane proteins using cell-free expression (CFE) systems has been proved to be challenging mainly due to the lack of necessary machinery for proper folding and translocation of nascent membrane proteins and their delivery to the supplied synthetic bilayers. Here, we provide protocols for detergent-free, cell-free reconstitution of functional membrane proteins using HeLa-based CFE system and outline assays for studying their membrane insertion, topology, and their orientation upon incorporation into the supported lipid bilayers or bilayers of giant unilamellar vesicles as well as methods to isolate functional translocated cell-free produced membrane proteins.
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Affiliation(s)
| | - Yen-Yu Hsu
- University of Michigan, Ann Arbor, MI, USA
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2
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Eto H, Franquelim HG, Heymann M, Schwille P. Membrane-coated 3D architectures for bottom-up synthetic biology. SOFT MATTER 2021; 17:5456-5466. [PMID: 34106121 DOI: 10.1039/d1sm00112d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
One of the great challenges of bottom-up synthetic biology is to recreate the cellular geometry and surface functionality required for biological reactions. Of particular interest are lipid membrane interfaces where many protein functions take place. However, cellular 3D geometries are often complex, and custom-shaping stable lipid membranes on relevant spatial scales in the micrometer range has been hard to accomplish reproducibly. Here, we use two-photon direct laser writing to 3D print microenvironments with length scales relevant to cellular processes and reactions. We formed lipid bilayers on the surfaces of these printed structures, and we evaluated multiple combinatorial scenarios, where physiologically relevant membrane compositions were generated on several different polymer surfaces. Functional dynamic protein systems were reconstituted in vitro and their self-organization was observed in response to the 3D geometry. This method proves very useful to template biological membranes with an additional spatial dimension, and thus allows a better understanding of protein function in relation to the complex morphology of cells and organelles.
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Affiliation(s)
- Hiromune Eto
- Department for Cellular and Molecular Biophysics, Max Planck Institute for Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany.
| | - Henri G Franquelim
- Department for Cellular and Molecular Biophysics, Max Planck Institute for Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany.
| | - Michael Heymann
- Department for Cellular and Molecular Biophysics, Max Planck Institute for Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany. and Department of Intelligent Biointegrative Systems, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Pfaffenwaldring 57, 70569, Stuttgart, Germany
| | - Petra Schwille
- Department for Cellular and Molecular Biophysics, Max Planck Institute for Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany.
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3
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Garoli D, Yamazaki H, Maccaferri N, Wanunu M. Plasmonic Nanopores for Single-Molecule Detection and Manipulation: Toward Sequencing Applications. NANO LETTERS 2019; 19:7553-7562. [PMID: 31587559 DOI: 10.1021/acs.nanolett.9b02759] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Solid-state nanopore-based sensors are promising platforms for next-generation sequencing technologies, featuring label-free single-molecule sensitivity, rapid detection, and low-cost manufacturing. In recent years, solid-state nanopores have been explored due to their miscellaneous fabrication methods and their use in a wide range of sensing applications. Here, we highlight a novel family of solid-state nanopores which have recently appeared, namely plasmonic nanopores. The use of plasmonic nanopores to engineer electromagnetic fields around a nanopore sensor allows for enhanced optical spectroscopies, local control over temperature, thermophoresis of molecules and ions to/from the sensor, and trapping of entities. This Mini Review offers a comprehensive understanding of the current state-of-the-art plasmonic nanopores for single-molecule detection and biomolecular sequencing applications and discusses the latest advances and future perspectives on plasmonic nanopore-based technologies.
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Affiliation(s)
- Denis Garoli
- Istituto Italiano di Tecnologia , via Morego 30 , I-16163 , Genova , Italy
| | - Hirohito Yamazaki
- Department of Physics , Northeastern University , 360 Huntington Avenue , Boston , Massachusetts 02115 , United States
| | - Nicolò Maccaferri
- Physics and Materials Science Research Unit , University of Luxembourg , 162a avenue de la Faïencerie , L-1511 Luxembourg , Luxembourg
| | - Meni Wanunu
- Department of Physics , Northeastern University , 360 Huntington Avenue , Boston , Massachusetts 02115 , United States
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4
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Chimisso V, Maffeis V, Hürlimann D, Palivan CG, Meier W. Self-Assembled Polymeric Membranes and Nanoassemblies on Surfaces: Preparation, Characterization, and Current Applications. Macromol Biosci 2019; 20:e1900257. [PMID: 31549783 DOI: 10.1002/mabi.201900257] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/30/2019] [Indexed: 01/11/2023]
Abstract
Biomembranes play a crucial role in a multitude of biological processes, where high selectivity and efficiency are key points in the reaction course. The outstanding performance of biological membranes is based on the coupling between the membrane and biomolecules, such as membrane proteins. Polymer-based membranes and assemblies represent a great alternative to lipid ones, as their presence not only dramatically increases the mechanical stability of such systems, but also opens the scope to a broad range of chemical functionalities, which can be fine-tuned to selectively combine with a specific biomolecule. Tethering the membranes or nanoassemblies on a solid support opens the way to a class of functional surfaces finding application as sensors, biocomputing systems, molecular recognition, and filtration membranes. Herein, the design, physical assembly, and biomolecule attachment/insertion on/within solid-supported polymeric membranes and nanoassemblies are presented in detail with relevant examples. Furthermore, the models and applications for these materials are highlighted with the recent advances in each field.
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Affiliation(s)
- Vittoria Chimisso
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4056, Basel, Switzerland
| | - Viviana Maffeis
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4056, Basel, Switzerland
| | - Dimitri Hürlimann
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4056, Basel, Switzerland
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4056, Basel, Switzerland
| | - Wolfgang Meier
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4056, Basel, Switzerland
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5
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Feng X, Ma T, Yamaura D, Tadaki D, Hirano-Iwata A. Formation and Characterization of Air-Stable Lipid Bilayer Membranes Incorporated with Phthalocyanine Molecules. J Phys Chem B 2019; 123:6515-6520. [PMID: 31280566 DOI: 10.1021/acs.jpcb.9b05135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bilayer lipid membranes (BLMs) are used as basic frameworks for biosensors and biohybrid devices due to their unique properties, which include ultrathin thickness, ultrahigh resistivity, and self-assembling ability. However, BLMs can only form and maintain their structure in aqueous environments, which pose significant limitations to their use. In this work, we report on the formation of highly uniform hybrid BLMs at a water/air interface through self-assembly by simply doping the BLMs with a functional organic molecule, copper(II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (CuPc). By transferring the membrane onto substrates, we were able to produce stable hybrid BLMs under anhydrous conditions. Atomic force microscopy and X-ray diffraction measurements confirmed that the hybrid membranes were composed of single, highly uniform BLMs or stacks of BLMs. Fluorescence resonance energy transfer measurements indicated that the CuPc molecules were located between the hydrophobic tails of lipid molecules, forming a sandwich structure in the hybrid membranes. The hybrid BLMs fabricated by this method substantially expand the range of applications of BLMs to solid-state devices.
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6
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Puiggalí-Jou A, Del Valle LJ, Alemán C. Biomimetic hybrid membranes: incorporation of transport proteins/peptides into polymer supports. SOFT MATTER 2019; 15:2722-2736. [PMID: 30869096 DOI: 10.1039/c8sm02513d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Molecular sensing, water purification and desalination, drug delivery, and DNA sequencing are some striking applications of biomimetic hybrid membranes. These devices take advantage of biomolecules, which have gained excellence in their specificity and efficiency during billions of years, and of artificial materials that load the purified biological molecules and provide technological properties, such as robustness, scalability, and suitable nanofeatures to confine the biomolecules. Recent methodological advances allow more precise control of polymer membranes that support the biomacromolecules, and are expected to improve the design of the next generation of membranes as well as their applicability. In the first section of this review we explain the biological relevance of membranes, membrane proteins, and the classification used for the latter. After this, we critically analyse the different approaches employed for the production of highly selective hybrid membranes, focusing on novel materials made of self-assembled block copolymers and nanostructured polymers. Finally, a summary of the advantages and disadvantages of the different methodologies is presented and the main characteristics of biomimetic hybrid membranes are highlighted.
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Affiliation(s)
- Anna Puiggalí-Jou
- Departament d'Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019, Barcelona, Spain. and Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019, Barcelona, Spain
| | - Luis J Del Valle
- Departament d'Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019, Barcelona, Spain. and Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019, Barcelona, Spain
| | - Carlos Alemán
- Departament d'Enginyeria Química, EEBE, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. I2, 08019, Barcelona, Spain. and Barcelona Research Center for Multiscale Science and Engineering, Universitat Politècnica de Catalunya, C/Eduard Maristany, 10-14, Ed. C, 08019, Barcelona, Spain
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7
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Lefrançois P, Goudeau B, Arbault S. Electroformation of phospholipid giant unilamellar vesicles in physiological phosphate buffer. Integr Biol (Camb) 2018; 10:429-434. [DOI: 10.1039/c8ib00074c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a protocol to prepare phospholipid Giant Unilamellar Vesicles (GUVs) by electroformation in PBS physiological buffer.
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8
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Howard RJ, Carnevale V, Delemotte L, Hellmich UA, Rothberg BS. Permeating disciplines: Overcoming barriers between molecular simulations and classical structure-function approaches in biological ion transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:927-942. [PMID: 29258839 DOI: 10.1016/j.bbamem.2017.12.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 12/08/2017] [Accepted: 12/14/2017] [Indexed: 11/20/2022]
Abstract
Ion translocation across biological barriers is a fundamental requirement for life. In many cases, controlling this process-for example with neuroactive drugs-demands an understanding of rapid and reversible structural changes in membrane-embedded proteins, including ion channels and transporters. Classical approaches to electrophysiology and structural biology have provided valuable insights into several such proteins over macroscopic, often discontinuous scales of space and time. Integrating these observations into meaningful mechanistic models now relies increasingly on computational methods, particularly molecular dynamics simulations, while surfacing important challenges in data management and conceptual alignment. Here, we seek to provide contemporary context, concrete examples, and a look to the future for bridging disciplinary gaps in biological ion transport. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.
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Affiliation(s)
- Rebecca J Howard
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Box 1031, 17121 Solna, Sweden.
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, Department of Chemistry, Temple University, Philadelphia, PA 19122, USA.
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Theoretical Physics, KTH Royal Institute of Technology, Box 1031, 17121 Solna, Sweden.
| | - Ute A Hellmich
- Johannes Gutenberg University Mainz, Institute for Pharmacy and Biochemistry, Johann-Joachim-Becherweg 30, 55128 Mainz, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany.
| | - Brad S Rothberg
- Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA.
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9
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Mazur F, Bally M, Städler B, Chandrawati R. Liposomes and lipid bilayers in biosensors. Adv Colloid Interface Sci 2017; 249:88-99. [PMID: 28602208 DOI: 10.1016/j.cis.2017.05.020] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Biosensors for the rapid, specific, and sensitive detection of analytes play a vital role in healthcare, drug discovery, food safety, and environmental monitoring. Although a number of sensing concepts and devices have been developed, many longstanding challenges to obtain inexpensive, easy-to-use, and reliable sensor platforms remain largely unmet. Nanomaterials offer exciting possibilities for enhancing the assay sensitivity and for lowering the detection limits down to single-molecule resolution. In this review, we present an overview of liposomes and lipid bilayers in biosensing applications. Lipid assemblies in the form of spherical liposomes or two-dimensional planar membranes have been widely used in the design of biosensing assays; in particular, we highlight a number of recent promising developments of biosensors based on liposomes in suspension, liposome arrays, and lipid bilayers arrays. Assay sensitivity and specificity are discussed, advantages and drawbacks are reviewed, and possible further developments are outlined.
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10
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The Flip-Flop Diffusion Mechanism across Lipids in a Hybrid Bilayer Membrane. Biophys J 2017; 110:2451-2462. [PMID: 27276263 DOI: 10.1016/j.bpj.2016.04.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/03/2016] [Accepted: 04/25/2016] [Indexed: 12/31/2022] Open
Abstract
In this study, we examine the mechanism of flip-flop diffusion of proton carriers across the lipid layer of a hybrid bilayer membrane (HBM). The HBM consists of a lipid monolayer appended on top of a self-assembled monolayer containing a Cu-based O2 reduction catalyst on a Au electrode. The flip-flop diffusion rates of the proton carriers dictate the kinetics of O2 reduction by the electrocatalyst. By varying both the tail lengths of the proton carriers and the lipids, we find the combinations of lengths that maximize the flip-flop diffusion rate. These experimental results combined with biophysical modeling studies allow us to propose a detailed mechanism for transmembrane flip-flop diffusion in HBM systems, which involves the bending of the alkyl tail of the proton carrier as the rate-determining step. Additional studies with an unbendable proton carrier further validate these mechanistic findings.
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11
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Hirano-Iwata A, Ishinari Y, Yoshida M, Araki S, Tadaki D, Miyata R, Ishibashi K, Yamamoto H, Kimura Y, Niwano M. Reconstitution of Human Ion Channels into Solvent-free Lipid Bilayers Enhanced by Centrifugal Forces. Biophys J 2017; 110:2207-15. [PMID: 27224486 DOI: 10.1016/j.bpj.2016.04.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/11/2016] [Accepted: 04/11/2016] [Indexed: 12/26/2022] Open
Abstract
Artificially formed bilayer lipid membranes (BLMs) provide well-defined systems for functional analyses of various membrane proteins, including ion channels. However, difficulties associated with the integration of membrane proteins into BLMs limit the experimental efficiency and usefulness of such BLM reconstitution systems. Here, we report on the use of centrifugation to more efficiently reconstitute human ion channels in solvent-free BLMs. The method improves the probability of membrane fusion. Membrane vesicles containing the human ether-a-go-go-related gene (hERG) channel, the human cardiac sodium channel (Nav1.5), and the human GABAA receptor (GABAAR) channel were formed, and the functional reconstitution of the channels into BLMs via vesicle fusion was investigated. Ion channel currents were recorded in 67% of the BLMs that were centrifuged with membrane vesicles under appropriate centrifugal conditions (14-55 × g). The characteristic channel properties were retained for hERG, Nav1.5, and GABAAR channels after centrifugal incorporation into the BLMs. A comparison of the centrifugal force with reported values for the fusion force revealed that a centrifugal enhancement in vesicle fusion was attained, not by accelerating the fusion process but by accelerating the delivery of membrane vesicles to the surface of the BLMs, which led to an increase in the number of membrane vesicles that were available for fusion. Our method for enhancing the probability of vesicle fusion promises to dramatically increase the experimental efficiency of BLM reconstitution systems, leading to the realization of a BLM-based, high-throughput platform for functional assays of various membrane proteins.
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Affiliation(s)
- Ayumi Hirano-Iwata
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan.
| | - Yutaka Ishinari
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Miyu Yoshida
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Shun Araki
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Daisuke Tadaki
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | - Ryusuke Miyata
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan
| | | | - Hideaki Yamamoto
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aoba, Sendai, Japan
| | - Yasuo Kimura
- Department of Electric and Electronic Engineering, School of Engineering, Tokyo University of Technology, Hachioji, Tokyo, Japan
| | - Michio Niwano
- Graduate School of Biomedical Engineering, Tohoku University, Aoba, Sendai, Japan; Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Aoba, Sendai, Japan
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12
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Agasid MT, Comi TJ, Saavedra SS, Aspinwall CA. Enhanced Temporal Resolution with Ion Channel-Functionalized Sensors Using a Conductance-Based Measurement Protocol. Anal Chem 2017; 89:1315-1322. [PMID: 27981836 PMCID: PMC5862562 DOI: 10.1021/acs.analchem.6b04226] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The binding of a target analyte to an ion channel (IC), which is readily detected electrochemically in a label-free manner with single-molecule selectivity and specificity, has generated widespread interest in using natural and engineered ICs as transducers in biosensing platforms. To date, the majority of developments in IC-functionalized sensing have focused on IC selectivity or sensitivity or development of suitable membrane environments and aperture geometries. Comparatively little work has addressed analytical performance criteria, particularly criteria required for temporal measurements of dynamic processes. We report a measurement protocol suitable for rapid, time-resolved monitoring (≤30 ms) of IC-modulated membrane conductance. Key features of this protocol include the reduction of membrane area and the use of small voltage steps (10 mV) and short duration voltage pulses (10 ms), which have the net effect of reducing the capacitive charging and decreasing the time required to achieve steady state currents. Application of a conductance protocol employing three sequential, 10 ms voltage steps (-10 mV, -20 mV, -30 mV) in an alternating, pyramid-like arrangement enabled sampling of membrane conductance every 30 ms. Using this protocol, dynamic IC measurements on black lipid membranes (BLMs) functionalized with gramicidin A were conducted using a fast perfusion system. BLM conductance decreased by 76 ± 7.5% within 30 ms of switching from solutions containing 0 to 1 M Ca2+, which demonstrates the feasibility of using this approach to monitor rapid, dynamic chemical processes. Rapid conductance measurements will be broadly applicable to IC-based sensors that undergo analyte-specific gating.
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Affiliation(s)
- Mark T. Agasid
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - Troy J. Comi
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - S. Scott Saavedra
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
- BIO5 Institute, University of Arizona, Tucson, AZ 85721
| | - Craig A. Aspinwall
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
- BIO5 Institute, University of Arizona, Tucson, AZ 85721
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721
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13
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Affiliation(s)
- Toshihisa Osaki
- Artificial Cell
Membrane
Systems Group, Kanagawa Academy of Science and Technology, 3-2-1
Sakado, Takatsu, 213-0012 Kawasaki, Japan
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, 153-8505 Tokyo, Japan
| | - Shoji Takeuchi
- Artificial Cell
Membrane
Systems Group, Kanagawa Academy of Science and Technology, 3-2-1
Sakado, Takatsu, 213-0012 Kawasaki, Japan
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, 153-8505 Tokyo, Japan
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14
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Bilayer membrane interactions with nanofabricated scaffolds. Chem Phys Lipids 2015; 192:75-86. [DOI: 10.1016/j.chemphyslip.2015.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/16/2015] [Accepted: 07/25/2015] [Indexed: 01/17/2023]
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15
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Hirano-Iwata A, Ishinari Y, Yamamoto H, Niwano M. Micro- and Nano-Technologies for Lipid Bilayer-Based Ion-Channel Functional Assays. Chem Asian J 2015; 10:1266-74. [DOI: 10.1002/asia.201403391] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Ayumi Hirano-Iwata
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Yutaka Ishinari
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Hideaki Yamamoto
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Frontier Research Institute for Interdisciplinary Sciences; Tohoku University; 6-3 Aoba Aramaki, Aoba-ku Sendai 980-8578 Japan
| | - Michio Niwano
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Laboratory for Nanoelectronics and Spintronics; Research Institute of Electrical Communication; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
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16
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del Rio Martinez JM, Zaitseva E, Petersen S, Baaken G, Behrends JC. Automated formation of lipid membrane microarrays for ionic single-molecule sensing with protein nanopores. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:119-125. [PMID: 25115837 DOI: 10.1002/smll.201402016] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Indexed: 06/03/2023]
Abstract
Efficient use of membrane protein nanopores in ionic single-molecule sensing requires technology for the reliable formation of suspended molecular membranes densely arrayed in formats that allow high-resolution electrical recording. Here, automated formation of bimolecular lipid layers is shown using a simple process where a poly(tetrafluoroethylene)-coated magnetic bar is remotely actuated to perform a turning motion, thereby spreading phospholipid in organic solvent on a nonpolar surface containing a <1 mm(2) 4 × 4 array of apertures with embedded microelectrodes (microelectrode cavity array). Parallel and high-resolution single-molecule detection by single nanopores is demonstrated on the resulting bilayer arrays, which are shown to form by a classical but very rapid self-assembly process. The technique provides a robust and scalable solution for the problem of reliable, automated formation of multiple independent lipid bilayers in a dense microarray format, while preserving the favorable electrical properties of the microelectrode cavity array.
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Affiliation(s)
- Juan M del Rio Martinez
- Laboratory for Membrane Physiology and -Technology, Department of Physiology, University of Freiburg, Hermann-Herder-Str. 7, 79104, Freiburg, Germany
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17
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Weatherill EE, Wallace MI. Combining Single-Molecule Imaging and Single-Channel Electrophysiology. J Mol Biol 2015; 427:146-57. [DOI: 10.1016/j.jmb.2014.07.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/07/2014] [Accepted: 07/07/2014] [Indexed: 12/29/2022]
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18
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Horger KS, Liu H, Rao DK, Shukla S, Sept D, Ambudkar SV, Mayer M. Hydrogel-assisted functional reconstitution of human P-glycoprotein (ABCB1) in giant liposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:643-53. [PMID: 25450342 DOI: 10.1016/j.bbamem.2014.10.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 09/17/2014] [Accepted: 10/20/2014] [Indexed: 11/24/2022]
Abstract
This paper describes the formation of giant proteoliposomes containing P-glycoprotein (P-gp) from a solution of small proteoliposomes that had been deposited and partially dried on a film of agarose. This preparation method generated a significant fraction of giant proteoliposomes that were free of internalized vesicles, making it possible to determine the accessible liposome volume. Measuring the intensity of the fluorescent substrate rhodamine 123 (Rho123) inside and outside these giant proteoliposomes determined the concentration of transported substrates of P-gp. Fitting a kinetic model to the fluorescence data revealed the rate of passive diffusion as well as active transport by reconstituted P-gp in the membrane. This approach determined estimates for the membrane permeability coefficient (Ps) of passive diffusion and rate constants of active transport (kT) by P-gp as a result of different experimental conditions. The Ps value for Rho123 was larger in membranes containing P-gp under all assay conditions than in membranes without P-gp indicating increased leakiness in the presence of reconstituted transmembrane proteins. For P-gp liposomes, the kT value was significantly higher in the presence of ATP than in its absence or in the presence of ATP and the competitive inhibitor verapamil. This difference in kT values verified that P-gp was functionally active after reconstitution and quantified the rate of active transport. Lastly, patch clamp experiments on giant proteoliposomes showed ion channel activity consistent with a chloride ion channel protein that co-purified with P-gp. Together, these results demonstrate several advantages of using giant rather than small proteoliposomes to characterize transport properties of transport proteins and ion channels.
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Affiliation(s)
- Kim S Horger
- Department of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI 48109, USA
| | - Haiyan Liu
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA
| | - Divya K Rao
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA
| | - Suneet Shukla
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bethesda, MD 20814, USA
| | - David Sept
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA; Center for Computational Medicine and Bioinformatics, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA
| | - Suresh V Ambudkar
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bethesda, MD 20814, USA
| | - Michael Mayer
- Department of Chemical Engineering, University of Michigan, 2300 Hayward Street, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA.
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Gleisner M, Mey I, Barbot M, Dreker C, Meinecke M, Steinem C. Driving a planar model system into the 3(rd) dimension: generation and control of curved pore-spanning membrane arrays. SOFT MATTER 2014; 10:6228-6236. [PMID: 25012509 DOI: 10.1039/c4sm00702f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The generation of a regular array of micrometre-sized pore-spanning membranes that protrude from the underlying surface as a function of osmotic pressure is reported. Giant unilamellar vesicles are spread onto non-functionalized Si/SiO(2) substrates containing a highly ordered array of cavities with pore diameters of 850 nm, an interpore distance of 4 μm and a pore depth of 10 μm. The shape of the resulting pore-spanning membranes is controlled by applying an osmotic pressure difference between the bulk solution and the femtoliter-sized cavity underneath each membrane. By applying Young-Laplace's law assuming moderate lateral membrane tensions, the response of the membranes to the osmotic pressure difference can be theoretically well described. Protruded pore-spanning membranes containing the receptor lipid PIP(2) specifically bind the ENTH domain of epsin resulting in an enlargement of the protrusions and disappearance as a result of ENTH-domain induced defects in the membranes. These results are discussed in the context of an ENTH-domain induced reduction of lateral membrane tension and formation of defects as a result of helix insertion of the protein in the bilayer.
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Affiliation(s)
- Martin Gleisner
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany.
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Sleytr UB, Schuster B, Egelseer E, Pum D. S-layers: principles and applications. FEMS Microbiol Rev 2014; 38:823-64. [PMID: 24483139 PMCID: PMC4232325 DOI: 10.1111/1574-6976.12063] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 01/12/2023] Open
Abstract
Monomolecular arrays of protein or glycoprotein subunits forming surface layers (S-layers) are one of the most commonly observed prokaryotic cell envelope components. S-layers are generally the most abundantly expressed proteins, have been observed in species of nearly every taxonomical group of walled bacteria, and represent an almost universal feature of archaeal envelopes. The isoporous lattices completely covering the cell surface provide organisms with various selection advantages including functioning as protective coats, molecular sieves and ion traps, as structures involved in surface recognition and cell adhesion, and as antifouling layers. S-layers are also identified to contribute to virulence when present as a structural component of pathogens. In Archaea, most of which possess S-layers as exclusive wall component, they are involved in determining cell shape and cell division. Studies on structure, chemistry, genetics, assembly, function, and evolutionary relationship of S-layers revealed considerable application potential in (nano)biotechnology, biomimetics, biomedicine, and synthetic biology.
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Affiliation(s)
- Uwe B. Sleytr
- Institute of BiophysicsDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Bernhard Schuster
- Institute of Synthetic BiologyDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Eva‐Maria Egelseer
- Institute of BiophysicsDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
| | - Dietmar Pum
- Institute of BiophysicsDepartment of NanobiotechnologyUniversity of Natural Resources and Life SciencesViennaAustria
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21
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Peng PY, Chiang PC, Chao L. Controllable occurrence of free-standing lipid membranes on nanograting structured supports. ACS APPLIED MATERIALS & INTERFACES 2014; 6:12261-12269. [PMID: 24988277 DOI: 10.1021/am501861a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Supported lipid bilayers (SLBs) have been widely used to study protein-lipid membrane interactions because their planar geometry is suitable for many surface analysis tools. However, the friction coupling between the support and the membrane can influence the properties of biomolecules in the membrane. Many studies have attempted to span SLBs over nanostructured supports to create free-standing regions in SLBs for biosensor applications. However, membranes following the support surface contour are more frequently observed than are free-standing membranes on structured supports, indicating that the parameter range suitable for formation of free-standing SLBs might be narrow and more information is necessary to understand the required conditions. The objective of this study was to estimate the system energies of free-standing and contour-following membrane states and determine which state is the most energetically favorable under various conditions. For a lipid membrane preferring to stay close to the support, an energy reward occurs when they are in close proximity; however, increasing the contact area on a structured surface can result in an energy penalty because of the bending of the lipid bilayer. Whether the energy reward or the energy penalty dominates could determine the membrane state. We used the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and the Helfrich bending theory to relate the energy sizes to experimentally controllable parameters. We experimentally examined whether the membrane state followed the model prediction when we used various buffer ionic strengths, various lipid types, and nanograting supports with three different geometries. Because it is difficult to observe the experimental membrane state directly at the nanoscale, we developed a method to use the fluorescence recovery shape change after photobleaching to distinguish experimental membrane states at the micrometer scale. Our experimental results closely matched the theoretical predictions, suggesting that the developed model can be used to predict suitable conditions for formation of free-standing bilayers on nanostructured solid supports.
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Affiliation(s)
- Po-Yu Peng
- Department of Chemical Engineering, National Taiwan University , Taipei 106, Taiwan
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22
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Schuster B, Sleytr UB. Biomimetic interfaces based on S-layer proteins, lipid membranes and functional biomolecules. J R Soc Interface 2014; 11:20140232. [PMID: 24812051 PMCID: PMC4032536 DOI: 10.1098/rsif.2014.0232] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/15/2014] [Indexed: 12/20/2022] Open
Abstract
Designing and utilization of biomimetic membrane systems generated by bottom-up processes is a rapidly growing scientific and engineering field. Elucidation of the supramolecular construction principle of archaeal cell envelopes composed of S-layer stabilized lipid membranes led to new strategies for generating highly stable functional lipid membranes at meso- and macroscopic scale. In this review, we provide a state-of-the-art survey of how S-layer proteins, lipids and polymers may be used as basic building blocks for the assembly of S-layer-supported lipid membranes. These biomimetic membrane systems are distinguished by a nanopatterned fluidity, enhanced stability and longevity and, thus, provide a dedicated reconstitution matrix for membrane-active peptides and transmembrane proteins. Exciting areas in the (lab-on-a-) biochip technology are combining composite S-layer membrane systems involving specific membrane functions with the silicon world. Thus, it might become possible to create artificial noses or tongues, where many receptor proteins have to be exposed and read out simultaneously. Moreover, S-layer-coated liposomes and emulsomes copying virus envelopes constitute promising nanoformulations for the production of novel targeting, delivery, encapsulation and imaging systems.
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Affiliation(s)
- Bernhard Schuster
- Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Institute for Synthetic Bioarchitectures, Muthgasse 11, 1190 Vienna, Austria
| | - Uwe B. Sleytr
- Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Institute for Biophysics, Muthgasse 11, 1190 Vienna, Austria
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Kalsi S, Powl AM, Wallace BA, Morgan H, de Planque MRR. Shaped apertures in photoresist films enhance the lifetime and mechanical stability of suspended lipid bilayers. Biophys J 2014; 106:1650-9. [PMID: 24739164 PMCID: PMC4008792 DOI: 10.1016/j.bpj.2014.02.033] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 02/12/2014] [Accepted: 02/26/2014] [Indexed: 11/22/2022] Open
Abstract
Planar lipid bilayers suspended in apertures provide a controlled environment for ion channel studies. However, short lifetimes and poor mechanical stability of suspended bilayers limit the experimental throughput of bilayer electrophysiology experiments. Although bilayers are more stable in smaller apertures, ion channel incorporation through vesicle fusion with the suspended bilayer becomes increasingly difficult. In an alternative bilayer stabilization approach, we have developed shaped apertures in SU8 photoresist that have tapered sidewalls and a minimum diameter between 60 and 100 μm. Bilayers formed at the thin tip of these shaped apertures, either with the painting or the folding method, display drastically increased lifetimes, typically >20 h, and mechanical stability, being able to withstand extensive perturbation of the buffer solution. Single-channel electrical recordings of the peptide alamethicin and of the proteoliposome-delivered potassium channel KcsA demonstrate channel conductance with low noise, made possible by the small capacitance of the 50 μm thick SU8 septum, which is only thinned around the aperture, and unimpeded proteoliposome fusion, enabled by the large aperture diameter. We anticipate that these shaped apertures with micrometer edge thickness can substantially enhance the throughput of channel characterization by bilayer lipid membrane electrophysiology, especially in combination with automated parallel bilayer platforms.
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Affiliation(s)
- Sumit Kalsi
- Electronics and Computer Science, University of Southampton, Southampton, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton, United Kingdom.
| | - Andrew M Powl
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - B A Wallace
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
| | - Hywel Morgan
- Electronics and Computer Science, University of Southampton, Southampton, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Maurits R R de Planque
- Electronics and Computer Science, University of Southampton, Southampton, United Kingdom; Institute for Life Sciences, University of Southampton, Southampton, United Kingdom.
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de Groot GW, Demarche S, Santonicola MG, Tiefenauer L, Vancso GJ. Smart polymer brush nanostructures guide the self-assembly of pore-spanning lipid bilayers with integrated membrane proteins. NANOSCALE 2014; 6:2228-37. [PMID: 24425208 DOI: 10.1039/c3nr05356c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nanopores in arrays on silicon chips are functionalized with pH-responsive poly(methacrylic acid) (PMAA) brushes and used as supports for pore-spanning lipid bilayers with integrated membrane proteins. Robust platforms are created by the covalent grafting of polymer brushes using surface-initiated atom transfer radical polymerization (ATRP), resulting in sensor chips that can be successfully reused over several assays. His-tagged proteins are selectively and reversibly bound to the nitrilotriacetic acid (NTA) functionalization of the PMAA brush, and consequently lipid bilayer membranes are formed. The enhanced membrane resistance as determined by electrochemical impedance spectroscopy and free diffusion of dyed lipids observed as fluorescence recovery after photobleaching confirmed the presence of lipid bilayers. Immobilization of the His-tagged membrane proteins on the NTA-modified PMAA brush near the pore edges is characterized by fluorescence microscopy. This system allows us to adjust the protein density in free-standing bilayers, which are stabilized by the polymer brush underneath. The potential application of the integrated platform for ion channel protein assays is demonstrated.
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Affiliation(s)
- G Wilhelmina de Groot
- Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.
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25
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King PH, Jones G, Morgan H, de Planque MRR, Zauner KP. Interdroplet bilayer arrays in millifluidic droplet traps from 3D-printed moulds. LAB ON A CHIP 2014; 14:722-9. [PMID: 24336841 DOI: 10.1039/c3lc51072g] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In droplet microfluidics, aqueous droplets are typically separated by an oil phase to ensure containment of molecules in individual droplets of nano-to-picoliter volume. An interesting variation of this method involves bringing two phospholipid-coated droplets into contact to form a lipid bilayer in-between the droplets. These interdroplet bilayers, created by manual pipetting of microliter droplets, have proved advantageous for the study of membrane transport phenomena, including ion channel electrophysiology. In this study, we adapted the droplet microfluidics methodology to achieve automated formation of interdroplet lipid bilayer arrays. We developed a 'millifluidic' chip for microliter droplet generation and droplet packing, which is cast from a 3D-printed mould. Droplets of 0.7-6.0 μL volume were packed as homogeneous or heterogeneous linear arrays of 2-9 droplets that were stable for at least six hours. The interdroplet bilayers had an area of up to 0.56 mm(2), or an equivalent diameter of up to 850 μm, as determined from capacitance measurements. We observed osmotic water transfer over the bilayers as well as sequential bilayer lysis by the pore-forming toxin melittin. These millifluidic interdroplet bilayer arrays combine the ease of electrical and optical access of manually pipetted microdroplets with the automation and reproducibility of microfluidic technologies. Moreover, the 3D-printing based fabrication strategy enables the rapid implementation of alternative channel geometries, e.g. branched arrays, with a design-to-device time of just 24-48 hours.
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Affiliation(s)
- Philip H King
- Electronics and Computer Science & Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
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26
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Simon A, Gounou C, Tan S, Tiefenauer L, Di Berardino M, Brisson AR. Free-standing lipid films stabilized by Annexin-A5. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2739-44. [DOI: 10.1016/j.bbamem.2013.07.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 07/16/2013] [Accepted: 07/24/2013] [Indexed: 10/26/2022]
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Friddin MS, Morgan H, de Planque MRR. Cell-free protein expression systems in microdroplets: Stabilization of interdroplet bilayers. BIOMICROFLUIDICS 2013; 7:14108. [PMID: 24404000 PMCID: PMC3579860 DOI: 10.1063/1.4791651] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/29/2013] [Indexed: 05/29/2023]
Abstract
Cell-free protein expression with bacterial lysates has been demonstrated to produce soluble proteins in microdroplets. However, droplet assays with expressed membrane proteins require the presence of a lipid bilayer. A bilayer can be formed in between lipid-coated aqueous droplets by bringing these into contact by electrokinetic manipulation in a continuous oil phase, but it is not known whether such interdroplet bilayers are compatible with high concentrations of biomolecules. In this study, we have characterized the lifetime and the structural integrity of interdroplet bilayers by measuring the bilayer current in the presence of three different commercial cell-free expression mixtures and their individual components. Samples of pure proteins and of a polymer were included for comparison. It is shown that complete expression mixtures reduce the bilayer lifetime to several minutes or less, and that this is mainly due to the lysate fraction itself. The fraction that contains the molecules for metabolic energy generation does not reduce the bilayer lifetime but does give rise to current steps that are indicative of lipid packing defects. Gel electrophoresis confirmed that proteins are only present at significant amounts in the lysate fractions and, when supplied separately, in the T7 enzyme mixture. Interestingly, it was also found that pure-protein and pure-polymer solutions perturb the interdroplet bilayer at higher concentrations; 10% (w/v) polyethylene glycol 8000 (PEG 8000) and 3 mM lysozyme induce large bilayer currents without a reduction in bilayer lifetime, whereas 3 mM albumin causes rapid bilayer failure. It can, therefore, be concluded that the high protein content of the lysates and the presence of PEG polymer, a typical lysate supplement, compromise the structural integrity of interdroplet bilayers. However, we established that the addition of lipid vesicles to the cell-free expression mixture stabilizes the interdroplet bilayer, allowing the exposure of interdroplet bilayers to cell-free expression solutions. Given that cell-free expressed membrane proteins can insert in lipid bilayers, we envisage that microdroplet technology may be extended to the study of in situ expressed membrane receptors and ion channels.
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Affiliation(s)
- Mark S Friddin
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Hywel Morgan
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Maurits R R de Planque
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom
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Arslan Yildiz A, Kang C, Sinner EK. Biomimetic membrane platform containing hERG potassium channel and its application to drug screening. Analyst 2013; 138:2007-12. [DOI: 10.1039/c3an36159d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Friddin MS, Smithers NP, Beaugrand M, Marcotte I, Williamson PTF, Morgan H, de Planque MRR. Single-channel electrophysiology of cell-free expressed ion channels by direct incorporation in lipid bilayers. Analyst 2013; 138:7294-8. [DOI: 10.1039/c3an01540h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Abstract
Lipid bilayers are natural barriers of biological cells and cellular compartments. Membrane proteins integrated in biological membranes enable vital cell functions such as signal transduction and the transport of ions or small molecules. In order to determine the activity of a protein of interest at defined conditions, the membrane protein has to be integrated into artificial lipid bilayers immobilized on a surface. For the fabrication of such biosensors expertise is required in material science, surface and analytical chemistry, molecular biology and biotechnology. Specifically, techniques are needed for structuring surfaces in the micro- and nanometer scale, chemical modification and analysis, lipid bilayer formation, protein expression, purification and solubilization, and most importantly, protein integration into engineered lipid bilayers. Electrochemical and optical methods are suitable to detect membrane activity-related signals. The importance of structural knowledge to understand membrane protein function is obvious. Presently only a few structures of membrane proteins are solved at atomic resolution. Functional assays together with known structures of individual membrane proteins will contribute to a better understanding of vital biological processes occurring at biological membranes. Such assays will be utilized in the discovery of drugs, since membrane proteins are major drug targets.
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Zagnoni M. Miniaturised technologies for the development of artificial lipid bilayer systems. LAB ON A CHIP 2012; 12:1026-1039. [PMID: 22301684 DOI: 10.1039/c2lc20991h] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Artificially reproducing cellular environments is a key aim of synthetic biology, which has the potential to greatly enhance our understanding of cellular mechanisms. Microfluidic and lab-on-a-chip (LOC) techniques, which enable the controlled handling of sub-microlitre volumes of fluids in an automated and high-throughput manner, can play a major role in achieving this by offering alternative and powerful methodologies in an on-chip format. Such techniques have been successfully employed over the last twenty years to provide innovative solutions for chemical analysis and cell-, molecular- and synthetic- biology. In the context of the latter, the formation of artificial cell membranes (or artificial lipid bilayers) that incorporate membrane proteins within miniaturised LOC architectures offers huge potential for the development of highly sensitive molecular sensors and drug screening applications. The aim of this review is to give a comprehensive and critical overview of the field of microsystems for creating and exploiting artificial lipid bilayers. Advantages and limitations of three of the most popular approaches, namely suspended, supported and droplet-based lipid bilayers, are discussed. Examples are reported that show how artificial cell membrane microsystems, by combining together biological procedures and engineering techniques, can provide novel methodologies for basic biological and biophysical research and for the development of biotechnology tools.
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Affiliation(s)
- Michele Zagnoni
- Centre for Microsystems and Photonics, University of Strathclyde, Glasgow, UK.
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Schottdorf M, Hofmann B, Kätelhön E, Offenhäusser A, Wolfrum B. Frequency-dependent signal transfer at the interface between electrogenic cells and nanocavity electrodes. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:031917. [PMID: 22587133 DOI: 10.1103/physreve.85.031917] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/24/2012] [Indexed: 05/31/2023]
Abstract
We present a model to describe the response of chip-based nanocavity sensors during extracellular recording of action potentials. These sensors feature microelectrodes which are embedded in liquid-filled cavities. They can be used for the highly localized detection of electrical signals on a chip. We calculate the sensor's impedance and simulate the propagation of action potentials. Subsequently we apply our findings to analyze cell-chip coupling properties. The results are compared to experimental data obtained from cardiomyocyte-like cells. We show that both the impedance and the modeled action potentials fit the experimental data well. Furthermore, we find evidence for a large seal resistance of cardiomyocytes on nanocavity sensors compared to conventional planar recording systems.
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Affiliation(s)
- Manuel Schottdorf
- Institute of Bioelectronics (PGI-8/ICS-8), Forschungszentrum Jülich GmbH, Jülich, Germany.
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Castell OK, Berridge J, Wallace MI. Quantification of Membrane Protein Inhibition by Optical Ion Flux in a Droplet Interface Bilayer Array. Angew Chem Int Ed Engl 2012; 51:3134-8. [DOI: 10.1002/anie.201107343] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 01/24/2012] [Indexed: 01/01/2023]
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34
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Castell OK, Berridge J, Wallace MI. Quantification of Membrane Protein Inhibition by Optical Ion Flux in a Droplet Interface Bilayer Array. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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