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Drab E, Sugihara K. Cooperative Function of LL-37 and HNP1 Protects Mammalian Cell Membranes from Lysis. Biophys J 2020; 119:2440-2450. [PMID: 33157121 DOI: 10.1016/j.bpj.2020.10.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/08/2020] [Indexed: 01/10/2023] Open
Abstract
LL-37, cleaved from human cathelicidin, and human neutrophil peptide-1 (HNP1) from the defensin family are antimicrobial peptides that are occasionally co-released from neutrophils, which synergistically kill bacteria. We report that this couple presents another type of cooperativity against host eukaryotic cells, in which they antagonistically minimize cytotoxicity by protecting membranes from lysis. Our results describe the potential of the LL-37/HNP1 cooperativity that switches from membrane-destructive to membrane-protective functions, depending on whether the target is an enemy or a host.
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Affiliation(s)
- Ewa Drab
- Department of Physical Chemistry, University of Geneva, Geneva, Switzerland
| | - Kaori Sugihara
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan; Department of Physical Chemistry, University of Geneva, Geneva, Switzerland.
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2
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Affiliation(s)
- Johann Nuck
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland
| | - Kaori Sugihara
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba Meguro-Ku, Tokyo 153-8505, Japan
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3
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Abstract
Biological nanopores reconstituted into supported lipid bilayer membranes are widely used as a platform for stochastic nanopore sensing with the ability to detect single molecules including, for example, single-stranded DNA (ssDNA) and miRNA. A main thrust in this area of research has been to improve overall bilayer stability and ease of measurements. These improvements are achieved through a variety of clever strategies including droplet-based techniques; however, they typically require specific microfabrication techniques to prepare devices or special manipulation techniques for microdroplets. Here, we describe a new method to prepare lipid bilayers using a recessed-in-glass Ag/AgCl microelectrode as a support structure. The lipid bilayer is formed at the tip of the microelectrode by immersing the microelectrode into a layered bath solution consisting of an oil/lipid mixture and an aqueous electrolyte solution. In this paper, we demonstrate this stable, supported lipid bilayer structure for channel current measurements of pore-forming toxins and single-molecule detection of ssDNA. This Ag/AgCl-supported lipid bilayer can potentially be widely adopted as a lipid membrane platform for nanopore sensing because of its simple and easy procedure needed to prepare lipid bilayers.
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Affiliation(s)
- Kan Shoji
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States.,Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184-8588, Japan.,Department of Mechanical Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan
| | - Ryuji Kawano
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184-8588, Japan
| | - Ryan J White
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States.,Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, Ohio 45221, United States
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4
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Tsemperouli M, Amstad E, Sakai N, Matile S, Sugihara K. Black Lipid Membranes: Challenges in Simultaneous Quantitative Characterization by Electrophysiology and Fluorescence Microscopy. Langmuir 2019; 35:8748-8757. [PMID: 31244250 DOI: 10.1021/acs.langmuir.9b00673] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Horizontal black lipid membranes (BLMs) enable optical microscopy to be combined with the electrophysiological measurements for studying ion channels, peptide pores, and ionophores. However, a careful literature review reveals that simultaneous fluorescence and electrical recordings in horizontal BLMs have been rarely reported for an unclear reason, whereas many works employ bright-field microscopy instead of fluorescence microscopy or perform fluorescence imaging and electrical measurements one after another separately without truly exploiting the advantage of the combined setup. In this work, the major causes related to the simultaneous electrical and fluorescence recordings in horizontal BLMs are identified, and several solutions to counteract the issue are also proposed.
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Affiliation(s)
- Maria Tsemperouli
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
| | - Esther Amstad
- Institute of Materials , Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne , Switzerland
| | - Naomi Sakai
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
| | - Stefan Matile
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
| | - Kaori Sugihara
- School of Chemistry and Biochemistry , University of Geneva , CH-1211 Geneva , Switzerland
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5
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Liu J, Xiao S, Li J, Yuan B, Yang K, Ma Y. Molecular details on the intermediate states of melittin action on a cell membrane. Biochimica et Biophysica Acta (BBA) - Biomembranes 2018; 1860:2234-41. [DOI: 10.1016/j.bbamem.2018.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/10/2018] [Accepted: 09/07/2018] [Indexed: 01/10/2023]
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6
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Abstract
We report a platform based on lateral nano-black lipid membranes (nano-BLMs), where electrical measurements and fluorescence microscopy setup are combined, for the calibration of di-4-ANEPPS, a common voltage sensitive dye (VSD). The advantage of this setup is (1) its flexibility in the choice of lipids and applied voltages, (2) its high stability that enables a high voltage (500 mV) application and long-time measurements and (3) its fluorescence microscopy readout, which can be directly correlated with other fluorescence microscopy experiments using VSDs (e.g. membrane potential measurements in living cells). Using this setup, we observed that the calibration curve of di-4-ANEPPS is strongly dependent on the net electric charge of the lipids. The developed setup can be used to calibrate VSDs in different lipid environments in order to better understand their fundamental voltage-sensing mechanism in the future.
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Affiliation(s)
- Maria Tsemperouli
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
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7
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Khan MS, Dosoky NS, Mustafa G, Patel D, Berdiev B, Williams JD. Electrophysiology of Epithelial Sodium Channel (ENaC) Embedded in Supported Lipid Bilayer Using a Single Nanopore Chip. Langmuir 2017; 33:13680-13688. [PMID: 29131643 DOI: 10.1021/acs.langmuir.7b02404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanopore-based technologies are highly adaptable supports for developing label-free sensor chips to characterize lipid bilayers, membrane proteins, and nucleotides. We utilized a single nanopore chip to study the electrophysiology of the epithelial Na+ channel (ENaC) incorporated in supported lipid membrane (SLM). An isolated nanopore was developed inside the silicon cavity followed by fusing large unilamellar vesicles (LUVs) of DPPS (1,2-dipalmitoyl-sn-glycero-3-phosphoserine) and DPPE (1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine) to produce a solvent-free SLM with giga-ohm (GΩ) sealed impedance. The presence and thickness of SLM on the nanopore chip were confirmed using atomic force spectroscopy. The functionality of SLM with and without ENaC was verified in terms of electrical impedance and capacitance by sweeping the frequency from 0.01 Hz to 100 kHz using electrochemical impedance spectroscopy. The nanopore chip exhibits long-term stability for the lipid bilayer before (144 h) and after (16 h) incorporation of ENaC. Amiloride, an inhibitor of ENaC, was utilized at different concentrations to test the integrity of fused ENaC in the lipid bilayer supported on a single nanopore chip. The developed model presents excellent electrical properties and improved mechanical stability of SLM, making this technology a reliable platform to study ion channel electrophysiology.
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Affiliation(s)
- Muhammad Shuja Khan
- Electrical and Computer Engineering Department, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
| | - Noura Sayed Dosoky
- Biotechnology Science and Engineering Program, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
| | - Ghulam Mustafa
- Department of Nuclear Medicine, The State University of New York at Buffalo , Buffalo, New York 14214, United States
| | - Darayas Patel
- Department of Mathematics and Computer Science, Oakwood University , Huntsville, Alabama 35896, United States
| | - Bakhrom Berdiev
- Department of Biomedical Sciences, Nazarbayev University School of Medicine , Astana 010000, Kazakhstan
| | - John Dalton Williams
- Electrical and Computer Engineering Department, University of Alabama in Huntsville , Huntsville, Alabama 35899, United States
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8
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Abstract
We have demonstrated colorimetric and fluorescence detection of a peptide, melittin, based on polydiacetylene (PDA) made of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DC(8,9)PC). The PDA used in this work has a phosphocholine headgroup, which mimics peptide-cell membrane interactions better than the conventional PDAs with carboxyl headgroups. The dose curve (colorimetric response vs. melittin concentration) showed a half maximum response at the melittin concentration of 0.1 mg ml-1, which is similar to that reported in traditional PDA assays. It suggests that the replacement of the headgroup was achieved without sacrificing the sensitivity. From the dose curve, the Hill coefficient was extracted as αHill = 2.1. The value is in agreement with the results from previous melittin studies with phospholipids, which reflects the benefit of having a biologically relevant headgroup. In addition, we found an unexpectedly slow spectral change when DC(8,9)PC-PDA was incubated with melittin. The origin of the time-dependent signal was studied by combining UV/VIS spectroscopy, fluorescence spectroscopy and dynamic light scattering.
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Affiliation(s)
- Roberto Diego Ortuso
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
| | - Ugo Cataldi
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
| | - Kaori Sugihara
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
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9
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Puiggalí-Jou A, Pérez-Madrigal MM, Del Valle LJ, Armelin E, Casas MT, Michaux C, Perpète EA, Estrany F, Alemán C. Confinement of a β-barrel protein in nanoperforated free-standing nanomembranes for ion transport. Nanoscale 2016; 8:16922-16935. [PMID: 27714137 DOI: 10.1039/c6nr04948f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Bioinspired free-standing nanomembranes (FSNMs) for selective ion transport have been tailored by immobilizing the Omp2a β-barrel membrane protein inside nanoperforations created in flexible poly(lactic acid) (PLA) nanomembranes. Perforated PLA FSNMs have been prepared by spin-coating a 99 : 1 PLA : poly(vinyl alcohol) mixture, and through a phase segregation process nanofeatures with dimensions similar to the entire nanomembrane thickness (∼110 nm) were induced. These nanofeatures have subsequently been transformed into nanoperforations (diameter: ∼51 nm) by selective solvent etching. The protein confined inside the nanopores of PLA FSNMs preserves the β-barrel structure and organizes in ovoid aggregates. The transport properties of Na+, K+, and Ca2+ across non-perforated PLA, nanoperforated PLA, and Omp2a-filled nanoperforated PLA have been monitored by measuring the nanomembrane resistance with electrochemical impedance spectroscopy (EIS). The incorporation of nanoperforations enhances the transport of ions across PLA nanomembranes, whereas the functionality of immobilized Omp2a is essential to exhibit effects similar to those observed in biological nanomembranes. Indeed, Omp2a-filled nanoperforated PLA nanomembranes exhibit stronger affinity towards Na+ and Ca2+ ions than towards K+. In summary, this work provides a novel bioinspired strategy to develop mechanically stable and flexible FSNMs with channels for ion transport, which are precisely located inside artificial nanoperforations, thus holding great potential for applications in biofiltration and biosensing.
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Affiliation(s)
- Anna Puiggalí-Jou
- Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028, Spain. and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C', C/Pasqual i Vila s/n, Barcelona E-08028, Spain
| | - Maria M Pérez-Madrigal
- Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028, Spain. and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C', C/Pasqual i Vila s/n, Barcelona E-08028, Spain
| | - Luis J Del Valle
- Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028, Spain. and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C', C/Pasqual i Vila s/n, Barcelona E-08028, Spain
| | - Elaine Armelin
- Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028, Spain. and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C', C/Pasqual i Vila s/n, Barcelona E-08028, Spain
| | - María T Casas
- Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028, Spain.
| | - Catherine Michaux
- Laboratoire de Chimie Physique des Biomolécules, Unité de Chimie Physique Théorique et Structurale (UCPTS), University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Eric A Perpète
- Laboratoire de Chimie Physique des Biomolécules, Unité de Chimie Physique Théorique et Structurale (UCPTS), University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium
| | - Francesc Estrany
- Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C', C/Pasqual i Vila s/n, Barcelona E-08028, Spain and Departament d'Enginyeria Química, Escola Universitària d'Enginyeria Tècnica Industrial de Barcelona, Universitat Politècnica de Catalunya, Comte d'Urgell 187, 08036 Barcelona, Spain
| | - Carlos Alemán
- Departament d'Enginyeria Química, ETSEIB, Universitat Politècnica de Catalunya, Avda. Diagonal 647, Barcelona E-08028, Spain. and Center for Research in Nano-Engineering, Universitat Politècnica de Catalunya, Campus Sud, Edifici C', C/Pasqual i Vila s/n, Barcelona E-08028, Spain
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10
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Tanaka A, Nakashima H, Kashimura Y, Sumitomo K. Electrostatically induced planar lipid membrane formation on a cationic hydrogel array by the fusion of small negatively charged unilamellar vesicles. Colloids Surf A Physicochem Eng Asp 2015. [DOI: 10.1016/j.colsurfa.2015.03.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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11
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Abstract
Many processes in life are based on ion currents and membrane voltages controlled by a sophisticated and diverse family of membrane proteins (ion channels), which are comparable in size to the most advanced nanoelectronic components currently under development. Here we demonstrate an electrical assay of individual ion channel activity by measuring the dynamic opening and closing of the ion channel nanopores using single-walled carbon nanotubes (SWNTs). Two canonical dynamic ion channels (gramicidin A (gA) and alamethicin) and one static biological nanopore (α-hemolysin (α-HL)) were successfully incorporated into supported lipid bilayers (SLBs, an artificial cell membrane), which in turn were interfaced to the carbon nanotubes through a variety of polymer-cushion surface functionalization schemes. The ion channel current directly charges the quantum capacitance of a single nanotube in a network of purified semiconducting nanotubes. This work forms the foundation for a scalable, massively parallel architecture of 1d nanoelectronic devices interrogating electrophysiology at the single ion channel level.
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Affiliation(s)
- Weiwei Zhou
- Integrated Nanosystems Research Facility, Department of Electrical Engineering and Computer Science, University of California Irvine, Irvine, CA, 92697 USA
| | - Yung Yu Wang
- Integrated Nanosystems Research Facility, Department of Electrical Engineering and Computer Science, University of California Irvine, Irvine, CA, 92697 USA
| | - Tae-Sun Lim
- Integrated Nanosystems Research Facility, Department of Electrical Engineering and Computer Science, University of California Irvine, Irvine, CA, 92697 USA
| | - Ted Pham
- Integrated Nanosystems Research Facility, Department of Electrical Engineering and Computer Science, University of California Irvine, Irvine, CA, 92697 USA
| | - Dheeraj Jain
- Integrated Nanosystems Research Facility, Department of Electrical Engineering and Computer Science, University of California Irvine, Irvine, CA, 92697 USA
| | - Peter J. Burke
- Integrated Nanosystems Research Facility, Department of Electrical Engineering and Computer Science, University of California Irvine, Irvine, CA, 92697 USA
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12
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Affiliation(s)
- Xuejing Wang
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Shenghua Ma
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Yingchun Su
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Ying Zhang
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Hongmei Bi
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
| | - Lixue Zhang
- Qingdao
Key Lab of Solar Energy Utilization and Energy Storage Technology,
Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao 266101, China
| | - Xiaojun Han
- State
Key Laboratory of Urban Water Resource and Environment, School of
Chemical Engineering and Technology, Harbin Institute of Technology, No. 92 West Da-Zhi Street, Harbin 150001, China
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13
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Abstract
Nanoscale biosensors provide the possibility to miniaturize optic, acoustic and electric sensors to the dimensions of biomolecules. This enables approaching single-molecule detection and new sensing modalities that probe molecular conformation. Nanoscale sensors are predominantly surface-based and label-free to exploit inherent advantages of physical phenomena allowing high sensitivity without distortive labeling. There are three main criteria to be optimized in the design of surface-based and label-free biosensors: (i) the biomolecules of interest must bind with high affinity and selectively to the sensitive area; (ii) the biomolecules must be efficiently transported from the bulk solution to the sensor; and (iii) the transducer concept must be sufficiently sensitive to detect low coverage of captured biomolecules within reasonable time scales. The majority of literature on nanoscale biosensors deals with the third criterion while implicitly assuming that solutions developed for macroscale biosensors to the first two, equally important, criteria are applicable also to nanoscale sensors. We focus on providing an introduction to and perspectives on the advanced concepts for surface functionalization of biosensors with nanosized sensor elements that have been developed over the past decades (criterion (iii)). We review in detail how patterning of molecular films designed to control interactions of biomolecules with nanoscale biosensor surfaces creates new possibilities as well as new challenges.
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Affiliation(s)
- Erik Reimhult
- Institute for Biologically Inspired Materials, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 11, A-1190 Vienna, Austria.
| | - Fredrik Höök
- Biological Physics, Department of Applied Physics, Chalmers University of Technology, Fysikgränd 3, SE-411 33 Göteborg, Sweden.
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14
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Xu F, Bao M, Rui L, Liu J, Li J, Dou Y, Yang K, Yuan B, Ma Y. Self-assembly of monolayered lipid membranes for surface-coating of a nanoconfined Bombyx mori silk fibroin film. RSC Adv 2015. [DOI: 10.1039/c5ra09683a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A self-assembled lipid membrane provides a smooth, hydrophilic and biocompatible surface coating film for materials.
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Affiliation(s)
- Fan Xu
- National Laboratory of Solid State Microstructures and Department of Physics
- Nanjing University
- Nanjing
- P. R. China
| | - Meimei Bao
- Center for Soft Condensed Matter Physics and Interdisciplinary Research
- Soochow University
- Suzhou
- P. R. China
- College of Physics
| | - Longfei Rui
- Center for Soft Condensed Matter Physics and Interdisciplinary Research
- Soochow University
- Suzhou
- P. R. China
- College of Physics
| | - Jiaojiao Liu
- Center for Soft Condensed Matter Physics and Interdisciplinary Research
- Soochow University
- Suzhou
- P. R. China
- College of Physics
| | - Jingliang Li
- Institute for Frontier Materials
- Deakin University
- Waurn Ponds
- Australia
| | - Yujiang Dou
- School of Electronic and Information Engineering
- Soochow University
- Suzhou
- P. R. China
| | - Kai Yang
- Center for Soft Condensed Matter Physics and Interdisciplinary Research
- Soochow University
- Suzhou
- P. R. China
- College of Physics
| | - Bing Yuan
- Center for Soft Condensed Matter Physics and Interdisciplinary Research
- Soochow University
- Suzhou
- P. R. China
- College of Physics
| | - Yuqiang Ma
- National Laboratory of Solid State Microstructures and Department of Physics
- Nanjing University
- Nanjing
- P. R. China
- Center for Soft Condensed Matter Physics and Interdisciplinary Research
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15
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Fegyver E, Mészáros R. Fine-tuning the nonequilibrium behavior of oppositely charged macromolecule/surfactant mixtures via the addition of nonionic amphiphiles. Langmuir 2014; 30:15114-15126. [PMID: 25469711 DOI: 10.1021/la503928x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The various commercial applications of oppositely charged polyelectrolytes (P) and ionic surfactants (S) with added nonionic amphiphiles initiated intensive research on the polyion/mixed surfactant interaction. A large group of earlier studies revealed that one of the major effects of the nonionic cosurfactants is the suppression of the associative phase separation of P/S systems. In contrast, recent studies indicated that in the dilute surfactant concentration range the added uncharged amphiphile enhances the precipitation concentration range. In order to rationalize these observations, the mixtures of poly(diallyldimethylammonium chloride) (PDADMAC), sodium dodecyl sulfate (SDS), and dodecyl maltoside (C12G2) are investigated using a variety of experimental methods. It is shown that the nonionic cosurfactant has two distinct and competing impacts on the mixed surfactant binding onto the polyions. The composition dependent variation of the chemical potentials of the amphiphiles determines which of these effects is the dominant one, explaining the seemingly diverse earlier observations and their interpretations. We also demonstrate that the nonionic amphiphile affects considerably the nonequilibrium features of polyion/ionic surfactant complexation. Namely, the presence of the uncharged surfactant can destabilize the colloidal dispersion of P/S nanoparticles formed in the two-phase composition range. However, at the same concentration range highly stable dispersions of polyion/mixed surfactant nanoparticles can be produced through the application of a new two-step solution preparation technique. This method is based on the order of addition effect of the two surfactants which can be utilized in future scientific and industrial applications.
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Affiliation(s)
- Edit Fegyver
- Laboratory of Interfaces and Nanosized Systems, Institute of Chemistry, Eötvös Loránd University , Pázmány Péter Sétány 1/A, Budapest 1117, Hungary
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16
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Mhanna R, Qiu F, Zhang L, Ding Y, Sugihara K, Zenobi-Wong M, Nelson BJ. Artificial bacterial flagella for remote-controlled targeted single-cell drug delivery. Small 2014; 10:1953-1957. [PMID: 24616145 DOI: 10.1002/smll.201303538] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/20/2014] [Indexed: 06/03/2023]
Affiliation(s)
- Rami Mhanna
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Székács I, Kaszás N, Gróf P, Erdélyi K, Szendrő I, Mihalik B, Pataki Á, Antoni FA, Madarász E. Optical waveguide lightmode spectroscopic techniques for investigating membrane-bound ion channel activities. PLoS One 2013; 8:e81398. [PMID: 24339925 PMCID: PMC3858217 DOI: 10.1371/journal.pone.0081398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 10/13/2013] [Indexed: 11/18/2022] Open
Abstract
Optical waveguide lightmode spectroscopic (OWLS) techniques were probed for monitoring ion permeation through channels incorporated into artificial lipid environment. A novel sensor set-up was developed by depositing liposomes or cell-derived membrane fragments onto hydrophilic polytetrafluoroethylene (PTFE) membrane. The fibrous material of PTFE membrane could entrap lipoid vesicles and the water-filled pores provided environment for the hydrophilic domains of lipid-embedded proteins. The sensor surface was kept clean from the lipid holder PTFE membrane by a water- and ion-permeable polyethylene terephthalate (PET) mesh. The sensor set-up was tested with egg yolk lecithin liposomes containing gramicidin ion channels and with cell-derived membrane fragments enriched in GABA-gated anion channels. The method allowed monitoring the move of Na+ and organic cations through gramicidin channels and detecting the Cl–-channel functions of the (α5β2γ2) GABAA receptor in the presence or absence of GABA and the competitive GABA-blocker bicuculline.
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Affiliation(s)
- Inna Székács
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
- * E-mail:
| | - Nóra Kaszás
- Semmelweis University, Department of Biophysics and Radiation Biology, Budapest, Hungary
| | - Pál Gróf
- Semmelweis University, Department of Biophysics and Radiation Biology, Budapest, Hungary
| | | | | | | | | | | | - Emilia Madarász
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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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 (BBA) - 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] [What about the content of this article? (0)] [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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Lu NY, Yang K, Li JL, Yuan B, Ma YQ. Vesicle deposition and subsequent membrane–melittin interactions on different substrates: A QCM-D experiment. Biochimica et Biophysica Acta (BBA) - Biomembranes 2013; 1828:1918-25. [DOI: 10.1016/j.bbamem.2013.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/21/2013] [Accepted: 04/12/2013] [Indexed: 01/08/2023]
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de Groot GW, Santonicola MG, Sugihara K, Zambelli T, Reimhult E, Vörös J, Vancso GJ. Switching transport through nanopores with pH-responsive polymer brushes for controlled ion permeability. ACS Appl Mater Interfaces 2013; 5:1400-1407. [PMID: 23360664 DOI: 10.1021/am302820y] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Several nanoporous platforms were functionalized with pH-responsive poly(methacrylic acid) (PMAA) brushes using surface-initiated atom transfer radical polymerization (SI-ATRP). The growth of the PMAA brush and its pH-responsive behavior from the nanoporous platforms were confirmed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM). The swelling behavior of the pH-responsive PMAA brushes grafted only from the nanopore walls was investigated by AFM in aqueous liquid environment with pH values of 4 and 8. AFM images displayed open nanopores at pH 4 and closed ones at pH 8, which rationalizes their use as gating platforms. Ion conductivity across the nanopores was investigated with current-voltage measurements at various pH values. Enhanced higher resistance across the nanopores was observed in a neutral polymer brush state (lower pH values) and lower resistance when the brush was charged (higher pH values). By adding a fluorescent dye in an environment of pH 4 or pH 8 at one side of the PMAA-brush functionalized nanopore array chips, diffusion across the nanopores was followed. These experiments displayed faster diffusion rates of the fluorescent molecules at pH 4 (PMAA neutral state, open pores) and slower diffusion at pH 8 (PMAA charged state, closed pores) showing the potential of this technology toward nanoscale valve applications.
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Affiliation(s)
- G Wilhelmina de Groot
- Materials Science and Technology of Polymers, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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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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Zhu ZW, Wang Y, Zhang X, Sun CF, Li MG, Yan JW, Mao BW. Electrochemical impedance spectroscopy and atomic force microscopic studies of electrical and mechanical properties of nano-black lipid membranes and size dependence. Langmuir 2012; 28:14739-14746. [PMID: 22985346 DOI: 10.1021/la303047v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present electrochemical impedance spectroscopic (EIS) and two-chamber AFM investigations of the electrical and mechanical properties of solvent-containing nano-BLMs suspended on chip-based nanopores of diameter of 200, 400, and 700 nm. The chips containing nanoporous silicon nitride membranes are fabricated based on low-cost colloidal lithography with low aspect ratio of the nanopores. BLMs of DPhPC lipid molecules are constructed across the nanopores by the painting method. Two equivalent circuits are compared in view of their adequacy in description of the EIS performances of the nano-BLMs and more importantly the structures associated with the nano-BLMs systems. The BLM resistance and capacitance as well as their size and time dependence are studied by EIS. The breakthrough forces, elasticity in terms of apparent spring constant, and lateral tension of the solvent-containing nano-BLMs are investigated by AFM force measurements. The exact relationship of the breakthrough force of the nano-BLM as a function of pore size is revealed. Both EIS and AFM studies show increasing lifetime and mechanical stability of the nano-BLMs with decreasing pore size. Finally, the robust 200 nm diameter nanopores are used to accommodate functional BLMs containing DPhPC lipid molecules and gramicidins by using a painting method with drop of mixture solutions of DPhPC and gramicidins. EIS investigation of the functional nano-BLMs is also performed.
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Affiliation(s)
- Zai-Wen Zhu
- State Key Laboratory of Physical Chemistry of the Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China
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Abstract
Formation of supported lipid bilayers on soft polymer cushions is a useful approach to decouple the membrane from the substrate for applications involving membrane proteins. We prepared biocompatible polymer cushions by the layer-by-layer assembly of two polysaccharide polyelectrolytes, chitosan (CHI) and hyaluronic acid, on glass and silicon substrates. (CHI/HA)(5) films were characterized by atomic force microscopy, giving an average thickness of 57 nm and roughness of 25 nm in aqueous solution at pH 6.5. Formation of zwitterionic lipid bilayers by the vesicle fusion method was attempted using DOPC vesicles at pH 4 and 6.5 on (CHI/HA)(5) films. At higher pH adsorbed lipids had low mobility and large immobile lipid fractions; a combination of fluorescence and AFM indicated that this was attributable to formation of poor quality membranes with defects and pinned lipids rather than to a layer of surface-adsorbed vesicles. By contrast, more uniform bilayers with mobile lipids were produced at pH 4. Fluorescence recovery after photobleaching gave diffusion coefficients that were similar to those for bilayers on PEG cushions and considerably higher than those measured on other polyelectrolyte films. The results suggest that the polymer surface charge is more important than the surface roughness in controlling formation of mobile supported bilayers. These results demonstrate that polysaccharides provide a useful alternative to other polymer cushions, particularly for applications where biocompatibility is important.
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Affiliation(s)
- Kirk Mulligan
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
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Lazzara TD, Carnarius C, Kocun M, Janshoff A, Steinem C. Separating attoliter-sized compartments using fluid pore-spanning lipid bilayers. ACS Nano 2011; 5:6935-6944. [PMID: 21797231 DOI: 10.1021/nn201266e] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Anodic aluminum oxide (AAO) is a porous material having aligned cylindrical compartments with 55-60 nm diameter pores, and being several micrometers deep. A protocol was developed to generate pore-spanning fluid lipid bilayers separating the attoliter-sized compartments of the nanoporous material from the bulk solution, while preserving the optical transparency of the AAO. The AAO was selectively functionalized by silane chemistry to spread giant unilamellar vesicles (GUVs) resulting in large continuous membrane patches covering the pores. Formation of fluid single lipid bilayers through GUV rupture could be readily observed by fluorescence microscopy and further supported by conservation of membrane surface area, before and after GUV rupture. Fluorescence recovery after photobleaching gave low immobile fractions (5-15%) and lipid diffusion coefficients similar to those found for bilayers on silica. The entrapment of molecules within the porous underlying cylindrical compartments, as well as the exclusion of macromolecules from the nanopores, demonstrate the barrier function of the pore-spanning membranes and could be investigated in three-dimensions using confocal laser scanning fluorescence imaging.
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Affiliation(s)
- Thomas D Lazzara
- Institute of Organic and Biomolecular Chemistry, Tammannstrasse 2, 37077 Göttingen, Germany
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Gornall JL, Mahendran KR, Pambos OJ, Steinbock LJ, Otto O, Chimerel C, Winterhalter M, Keyser UF. Simple reconstitution of protein pores in nano lipid bilayers. Nano Lett 2011; 11:3334-3340. [PMID: 21749149 DOI: 10.1021/nl201707d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We developed a new, simple and robust approach for rapid screening of single molecule interactions with protein channels. Our glass nanopipets can be fabricated simply by drawing glass capillaries in a standard pipet puller, in a matter of minutes, and do not require further modification before use. Giant unilamellar vesicles break when in contact with the tip of the glass pipet and form a supported bilayer with typical seal resistances of ∼140 GΩ, which is stable for hours and at applied potentials up to 900 mV. Bilayers can be formed, broken, and re-formed more than 50 times using the same pipet enabling rapid screening of bilayers for single protein channels. The stability of the lipid bilayer is significantly superior to that of traditionally built bilayers supported by Teflon membranes, particularly against perturbation by electrical and mechanical forces. We demonstrate the functional reconstitution of the E. coli porin OmpF and α-hemolysin in a glass nanopipet supported bilayer. Interactions of the antibiotic enrofloxacin with the OmpF channel have been studied at the single-molecule level, demonstrating the ability of this method to detect single molecule interactions with protein channels. High-resolution conductance measurements of protein channels can be performed with low sample and buffer consumption. Glass nanopipet supported bilayers are uniquely suited for single-molecule studies as they are more rigid and the lifetime of a stable membrane is on the scale of hours, closer to that of natural cell membranes.
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Affiliation(s)
- Joanne L Gornall
- Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, U.K
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Abstract
This review describes and discusses techniques useful for monitoring the activity of protein ion channels in vitro. In the first section the biological importance and the classification of ion channels are outlined in order to justify the strong motivation for dealing with this important class of membrane proteins. The expression, reconstitution and integration of recombinant proteins into lipid bilayers are crucial steps to obtain consistent data when working with ion channels. In the second section recording techniques used in research are presented. Since this review focuses on analytical systems bearing reconstituted ion channels the industrial most important patch-clamp techniques of cells are only briefly mentioned. In section three, artificial systems developed in the last decades are described while the emerging technologies using nanostructured supports or microfluidic systems are presented in section four. Finally, the remaining challenges of membrane protein analysis and its potential applications are briefly outlined.
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Affiliation(s)
- Sophie Demarche
- Biomolecular Research, Paul Scherrer Institut (PSI), CH-5232 Villigen, Switzerland
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Affiliation(s)
- Kaori Sugihara
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, CH-8092 Zurich, Switzerland
| | - János Vörös
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, CH-8092 Zurich, Switzerland
| | - Tomaso Zambelli
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, CH-8092 Zurich, Switzerland
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