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Guidelli R, Becucci L. Functional activity of peptide ion channels in tethered bilayer lipid membranes: Review. ELECTROCHEMICAL SCIENCE ADVANCES 2021. [DOI: 10.1002/elsa.202100180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Rolando Guidelli
- Department of Chemistry University of Florence Sesto Fiorentino Firenze Italy
| | - Lucia Becucci
- Ministero dell'Istruzione Scuola Media “Guglielmo Marconi” San Giovanni Valdarno Arezzo Italy
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2
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Why Do Tethered-Bilayer Lipid Membranes Suit for Functional Membrane Protein Reincorporation? APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11114876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Membrane proteins (MPs) are essential for cellular functions. Understanding the functions of MPs is crucial as they constitute an important class of drug targets. However, MPs are a challenging class of biomolecules to analyze because they cannot be studied outside their native environment. Their structure, function and activity are highly dependent on the local lipid environment, and these properties are compromised when the protein does not reside in the cell membrane. Mammalian cell membranes are complex and composed of different lipid species. Model membranes have been developed to provide an adequate environment to envisage MP reconstitution. Among them, tethered-Bilayer Lipid Membranes (tBLMs) appear as the best model because they allow the lipid bilayer to be decoupled from the support. Thus, they provide a sufficient aqueous space to envisage the proper accommodation of large extra-membranous domains of MPs, extending outside. Additionally, as the bilayer remains attached to tethers covalently fixed to the solid support, they can be investigated by a wide variety of surface-sensitive analytical techniques. This review provides an overview of the different approaches developed over the last two decades to achieve sophisticated tBLMs, with a more and more complex lipid composition and adapted for functional MP reconstitution.
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Ionophore properties of valinomycin in the model bilayer lipid membrane 1. Selectivity towards a cation. J Solid State Electrochem 2020. [DOI: 10.1007/s10008-020-04777-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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4
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Zhang Q, Liu Y, Li J, Xia X. Revealing the kinetics of ionophore facilitating ion transport across lipid bilayers by surface enhanced infrared absorption spectroscopy. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2019.08.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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5
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Su Z, Ran X, Leitch JJ, Schwan AL, Faragher R, Lipkowski J. How Valinomycin Ionophores Enter and Transport K + across Model Lipid Bilayer Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:16935-16943. [PMID: 31742409 DOI: 10.1021/acs.langmuir.9b03064] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Valinomycin, a cyclic peptide, was incorporated into a biomimetic lipid membrane tethered to the surface of a gold (111) electrode. Electrochemical impedance spectroscopy was used to study the ionophore properties of the peptide, and polarization modulation infrared reflection absorption spectroscopy was employed to determine the conformation and orientation of valinomycin in the membrane. The combination of these two techniques provided unique information about the ionophore mechanism where valinomycin transports ions across the membrane by creating a complex with potassium ions and forming an ion pair with a counter anion. The ion pair resides within the hydrophobic fragment of the membrane and adopts a small angle of ∼22° with respect to the surface normal. This novel study provides new insights explaining the valinomycin ion transport mechanism in model biological membranes.
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Affiliation(s)
- ZhangFei Su
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - XueQin Ran
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University (NanjingTech) , 30 South Puzhu Road , Nanjing 211816 , China
| | - J Jay Leitch
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Adrian L Schwan
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Robert Faragher
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Jacek Lipkowski
- Department of Chemistry , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
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6
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Gramicidin A ion channel formation in model phospholipid bilayers tethered to gold (111) electrode surfaces. Electrochim Acta 2017. [DOI: 10.1016/j.electacta.2017.05.059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Andersson J, Knobloch JJ, Perkins MV, Holt SA, Köper I. Synthesis and Characterization of Novel Anchorlipids for Tethered Bilayer Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:4444-4451. [PMID: 28387116 DOI: 10.1021/acs.langmuir.7b00778] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Tethered bilayer lipid membranes are versatile solid-supported model membrane systems. Core to these systems is an anchorlipid that covalently links a lipid bilayer to a support. The molecular structure of these lipids can have a significant impact on the properties of the resulting bilayer. Here, the synthesis of anchorlipids containing ester groups in the tethering part is described. The lipids are used to form bilayer membranes, and the resulting structures are compared with membranes formed using conventional anchorlipids or sparsely tethered membranes. All membranes showed good electrical sealing properties; the disulphide-terminated anchorlipids could be used in a sparsely tethered system without significantly reducing the sealing properties of the lipid bilayers. The sparsely tethered systems also allowed for higher ion transport across the membrane, which is in good correlation with higher hydration of the spacer region as seen by neutron scattering.
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Affiliation(s)
- Jakob Andersson
- Flinders Centre for Nanoscalce Science and Technology and School of Chemical and Physical Sciences, Flinders University , Adelaide 5042, Australia
| | - Jacqueline J Knobloch
- Flinders Centre for Nanoscalce Science and Technology and School of Chemical and Physical Sciences, Flinders University , Adelaide 5042, Australia
| | - Michael V Perkins
- Flinders Centre for Nanoscalce Science and Technology and School of Chemical and Physical Sciences, Flinders University , Adelaide 5042, Australia
| | - Stephen A Holt
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation , Locked Bag 2001, Kirrawee DC, New South Wales 2234, Australia
| | - Ingo Köper
- Flinders Centre for Nanoscalce Science and Technology and School of Chemical and Physical Sciences, Flinders University , Adelaide 5042, Australia
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Mech-Dorosz A, Heiskanen A, Bäckström S, Perry M, Muhammad HB, Hélix-Nielsen C, Emnéus J. A reusable device for electrochemical applications of hydrogel supported black lipid membranes. Biomed Microdevices 2015; 17:21. [PMID: 25653071 DOI: 10.1007/s10544-015-9936-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Black lipid membranes (BLMs) are significant in studies of membrane transport, incorporated proteins/ion transporters, and hence in construction of biosensor devices. Although BLMs provide an accepted mimic of cellular membranes, they are inherently fragile. Techniques are developed to stabilize them, such as hydrogel supports. In this paper, we present a reusable device for studies on hydrogel supported (hs) BLMs. These are formed across an ethylene tetrafluoroethylene (ETFE) aperture array supported by the hydrogel, which is during in situ polymerization covalently "sandwiched" between the ETFE substrate and a gold electrode microchip, thus allowing direct electrochemical studies with the integrated working electrodes. Using electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy and contact angle measurements, we demonstrate the optimized chemical modifications of the gold electrode microchips and plasma modification of the ETFE aperture arrays facilitating covalent "sandwiching" of the hydrogel. Both fluorescence microscopy and EIS were used to demonstrate the induced spontaneous thinning of a deposited lipid solution, leading to formation of stabilized hsBLMs on average in 10 min. The determined specific membrane capacitance and resistance were shown to vary in the range 0.31-0.49 μF/cm(2) and 45-65 kΩ cm(2), respectively, corresponding to partially solvent containing BLMs with an average life time of 60-80 min. The characterized hsBLM formation and devised equivalent circuit models lead to a schematic model to illustrate lipid molecule distribution in hydrogel-supported apertures. The functionality of stabilized hsBLMs and detection sensitivity of the platform were verified by monitoring the effect of the ion transporter valinomycin.
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Affiliation(s)
- Agnieszka Mech-Dorosz
- Department of Micro- and Nanotechnology, Technical University of Denmark, Produktionstorvet 423, 2800, Kgs. Lyngby, Denmark
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Damiati S, Schrems A, Sinner EK, Sleytr UB, Schuster B. Probing peptide and protein insertion in a biomimetic S-layer supported lipid membrane platform. Int J Mol Sci 2015; 16:2824-38. [PMID: 25633104 PMCID: PMC4346867 DOI: 10.3390/ijms16022824] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 01/08/2015] [Accepted: 01/22/2015] [Indexed: 11/17/2022] Open
Abstract
The most important aspect of synthetic lipid membrane architectures is their ability to study functional membrane-active peptides and membrane proteins in an environment close to nature. Here, we report on the generation and performance of a biomimetic platform, the S-layer supported lipid membrane (SsLM), to investigate the structural and electrical characteristics of the membrane-active peptide gramicidin and the transmembrane protein α-hemolysin in real-time using a quartz crystal microbalance with dissipation monitoring in combination with electrochemical impedance spectroscopy. A shift in membrane resistance is caused by the interaction of α-hemolysin and gramicidin with SsLMs, even if only an attachment onto, or functional channels through the lipid membrane, respectively, are formed. Moreover, the obtained results did not indicate the formation of functional α-hemolysin pores, but evidence for functional incorporation of gramicidin into this biomimetic architecture is provided.
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Affiliation(s)
- Samar Damiati
- Institute for Synthetic Bioarchitectures, Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, Vienna 1190, Austria.
| | - Angelika Schrems
- Institute for Synthetic Bioarchitectures, Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, Vienna 1190, Austria.
| | - Eva-Kathrin Sinner
- Institute for Synthetic Bioarchitectures, Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, Vienna 1190, Austria.
| | - Uwe B Sleytr
- Institute for Biophysics, Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, Vienna 1190, Austria.
| | - Bernhard Schuster
- Institute for Synthetic Bioarchitectures, Department of NanoBiotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, Vienna 1190, Austria.
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Liu Y, Mark Worden R. Size dependent disruption of tethered lipid bilayers by functionalized polystyrene nanoparticles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:67-75. [DOI: 10.1016/j.bbamem.2014.09.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/08/2014] [Accepted: 09/29/2014] [Indexed: 12/18/2022]
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11
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Stereoselective synthesis of perdeuterated phytanic acid, its phospholipid derivatives and their formation into lipid model membranes for neutron reflectivity studies. Chem Phys Lipids 2014; 183:22-33. [DOI: 10.1016/j.chemphyslip.2014.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Revised: 04/01/2014] [Accepted: 04/07/2014] [Indexed: 11/23/2022]
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12
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Becucci L, Faragher RJ, Schwan A. The effect of the hydrophilic spacer length on the functionality of a mercury-supported tethered bilayer lipid membrane. Bioelectrochemistry 2014; 101:92-6. [PMID: 25180906 DOI: 10.1016/j.bioelechem.2014.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 08/08/2014] [Accepted: 08/14/2014] [Indexed: 11/16/2022]
Abstract
A biomimetic membrane consisting of a thiolipid monolayer tethered to a mercury electrode, with a dioleoylphosphatidylcholine (DOPC) monolayer on top of it, was fabricated. The thiolipid, referred to as DPOL, consisted of an octaethyleneoxy (OEO) chain terminated at one end with a lipoic acid residue and covalently linked at the other end to two phytanyl chains. The functionality of this biomimetic membrane, referred to as a tethered bilayer lipid membrane (tBLM), was tested by incorporating gramicidin and alamethicin and verifying their ion channel activity. Advantages and drawbacks with respect to a tBLM using a thiolipid, referred to as DPTL, with a tetraethyleneoxy (TEO) chain were examined by using electrochemical impedance spectroscopy, potential-step chronocoulometry and cyclic voltammetry. The maximum charge surface density of potassium ions stored in the OEO spacer amounts to 70μCcm(-2), as compared to a charge surface density of 45μCcm(-2) in the TEO spacer. The lipid bilayer moiety of the DPOL/DOPC tBLM is somewhat leakier than that of the DPTL/DOPC tBLM at potentials negative of about -0.65V vs. the saturated calomel electrode. The estimated value of the surface dipole potential of the OEO spacer amounts to -0.180V and is, therefore, smaller than that, -0.230V, of the TEO spacer.
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Affiliation(s)
- Lucia Becucci
- Institute for the Chemistry of Organometallic Compounds (ICCOM) of the National Research Council, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Firenze, Italy.
| | - Robert J Faragher
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Adrian Schwan
- Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Liu Y, Zhang Z, Zhang Q, Baker GL, Worden RM. Biomembrane disruption by silica-core nanoparticles: effect of surface functional group measured using a tethered bilayer lipid membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:429-37. [PMID: 24060565 DOI: 10.1016/j.bbamem.2013.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/10/2013] [Accepted: 09/12/2013] [Indexed: 01/01/2023]
Abstract
Engineered nanomaterials (ENM) have desirable properties that make them well suited for many commercial applications. However, a limited understanding of how ENM's properties influence their molecular interactions with biomembranes hampers efforts to design ENM that are both safe and effective. This paper describes the use of a tethered bilayer lipid membrane (tBLM) to characterize biomembrane disruption by functionalized silica-core nanoparticles. Electrochemical impedance spectroscopy was used to measure the time trajectory of tBLM resistance following nanoparticle exposure. Statistical analysis of parameters from an exponential resistance decay model was then used to quantify and analyze differences between the impedance profiles of nanoparticles that were unfunctionalized, amine-functionalized, or carboxyl-functionalized. All of the nanoparticles triggered a decrease in membrane resistance, indicating nanoparticle-induced disruption of the tBLM. Hierarchical clustering allowed the potency of nanoparticles for reducing tBLM resistance to be ranked in the order amine>carboxyl~bare silica. Dynamic light scattering analysis revealed that tBLM exposure triggered minor coalescence for bare and amine-functionalized silica nanoparticles but not for carboxyl-functionalized silica nanoparticles. These results indicate that the tBLM method can reproducibly characterize ENM-induced biomembrane disruption and can distinguish the BLM-disruption patterns of nanoparticles that are identical except for their surface functional groups. The method provides insight into mechanisms of molecular interaction involving biomembranes and is suitable for miniaturization and automation for high-throughput applications to help assess the health risk of nanomaterial exposure or identify ENM having a desired mode of interaction with biomembranes.
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Affiliation(s)
- Ying Liu
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA
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Hassler BL, Worden RM, Mason AJ. A protein-based electrochemical biosensor array platform for integrated microsystems. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2013; 7:43-51. [PMID: 23853278 DOI: 10.1109/tbcas.2012.2195661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This paper elucidates challenges in integrating different classes of proteins into a microsystem and presents an electrochemical array strategy for heterogeneous protein-based biosensors. The overlapping requirements and limitations imposed by biointerface formation, electrochemical characterization, and microsystem fabrication are identified. A planar electrode array is presented that synergistically resolves these requirements using thin film Au and Ag/AgCl electrodes on a dielectric substrate. Using molecular self-assembly, electrodes were modified by nano-structures of two diverse proteins, alkali ion-channel protein and alcohol dehydrogenase enzyme. Electrochemical impedance spectroscopy and cyclic voltammetry measurements were performed to characterize sensor response to alkali ion and alcohol, respectively. This work demonstrates the viability of the electrochemical microsystem platform for heterogeneous protein-based biosensor interfaces.
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Jadhav SR, Rao KS, Zheng Y, Garavito RM, Worden RM. Voltage dependent closure of PorB class II porin from Neisseria meningitidis investigated using impedance spectroscopy in a tethered bilayer lipid membrane interface. J Colloid Interface Sci 2013; 390:211-6. [PMID: 23083768 DOI: 10.1016/j.jcis.2012.09.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 01/16/2023]
Abstract
Electrochemical impedance spectroscopy (EIS) was used to characterize voltage-dependent closure of PorB class II (PorBII) porin from Neisseria meningitidis incorporated in a tethered bilayer lipid membrane (tBLM). The tBLM's lower leaflet was fabricated by depositing a self assembled monolayer (SAM) of 1,2-dipalmitoyl-sn-glycero-3-phosphothioethanol (DPPTE) on a gold electrode, and the upper leaflet was formed by depositing1,2-dioleoyl-sn-glycero-3-phoshocholine (DOPC) liposomes. At 0mV bias DC potential, incorporation of PorBII decreased the membrane resistance (R(m)) from 2.5 MΩc m(2) to 0.6 MΩ cm(2), giving a ΔR(m) of 1.9 MΩ cm(2) and a normalized ΔR(m) (ΔR(m) divided by the R(m) of the tBLM without PorBII) of 76%. When the bias DC potential was increased to 200 mV, the normalized ΔR(m) value decreased to 20%. The effect of applied voltage on ΔR(m) was completely reversible, suggesting voltage-dependent closure of PorBII. The voltage dependence of PorBII was further studied in a planar bilayer lipid membrane made from 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhytPC). Following a single insertion event, PorBII exhibited multiple conductance states, with reversible, voltage-dependent closure of PorBII porin occurring at high transmembrane potentials. The trimetric porin closed in three discrete steps, each step corresponding to closure of one conducting monomer unit. The most probable single channel conductance was 4.2 nS. The agreement between results obtained with the tBLM and pBLM platforms demonstrates the utility of EIS to screen channel proteins immobilized in tBLM for voltage-gated behavior.
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Affiliation(s)
- Sachin R Jadhav
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA
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Application of Infrared Spectroscopy for Structural Analysis of Planar Lipid Bilayers Under Electrochemical Control. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-12-411515-6.00002-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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Al-Obeidi A, Ge C, Orosz KS, Saavedra SS. ITO/poly(aniline)/sol-gel glass: An optically transparent, pH-responsive substrate for supported lipid bilayers. JOURNAL OF MATERIALS 2013; 2013:676920. [PMID: 25328882 PMCID: PMC4201389 DOI: 10.1155/2013/676920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Described here is fabrication of a pH-sensitive, optically transparent transducer composed of a planar indium-tin oxide (ITO) electrode overcoated with a a poly(aniline) (PANI) thin film and a porous sol-gel layer. Adsorption of the PANI film renders the ITO electrode sensitive to pH, whereas the sol-gel spin-coated layer makes the upper surface compatible with fusion of phospholipid vesicles to form a planar supported lipid bilayer (PSLB). The response to changes in the pH of the buffer contacting the sol-gel/PANI/ITO electrode is pseudo-Nernstian with a slope of 52 mV/pH over a pH range of 4-9. Vesicle fusion forms a laterally continuous PSLB on the upper sol-gel surface that is fluid with a lateral lipid diffusion coefficient of 2.2 μm2/s measured by fluorescence recovery after photobleaching. Due to its lateral continuity and lack of defects, the PSLB blocks the pH response of the underlying electrode to changes in the pH of the overlying buffer. This architecture is simpler to fabricate than previously reported ITO electrodes derivatized for PSLB formation, and should be useful for optical monitoring of proton transport across supported membranes derivatized with ionophores and ion channels.
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Affiliation(s)
- Ahmed Al-Obeidi
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041
| | - Chenhao Ge
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041
| | - Kristina S. Orosz
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041
| | - S. Scott Saavedra
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721-0041
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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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Phospholipase A2 activity on supported thiolipid monolayers monitored by electrochemical and SPR methods. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.03.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Ge C, Orosz KS, Armstrong NR, Saavedra SS. Poly(aniline) nanowires in sol-gel coated ITO: a pH-responsive substrate for planar supported lipid bilayers. ACS APPLIED MATERIALS & INTERFACES 2011; 3:2677-85. [PMID: 21707069 PMCID: PMC3145051 DOI: 10.1021/am2004637] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Facilitated ion transport across an artificial lipid bilayer coupled to a solid substrate is a function common to several types of bioelectronic devices based on supported membranes, including biomimetic fuel cells and ion channel biosensors. Described here is fabrication of a pH-sensitive transducer composed of a porous sol-gel layer derivatized with poly(aniline) (PANI) nanowires grown from an underlying planar indium-tin oxide (ITO) electrode. The upper sol-gel surface is hydrophilic, smooth, and compatible with deposition of a planar supported lipid bilayer (PSLB) formed via vesicle fusion. Conducting tip AFM was used to show that the PANI wires are connected to the ITO, which convert this electrode into a potentiometric pH sensor. The response to changes in the pH of the buffer contacting the PANI nanowire/sol-gel/ITO electrode is blocked by the very low ion permeability of the overlying fluid PSLB. The feasibility of using this assembly to monitor facilitated proton transport across the PSLB was demonstrated by doping the membrane with lipophilic ionophores that respond to a transmembrane pH gradient, which produced an apparent proton permeability several orders of magnitude greater than values measured for undoped lipid bilayers.
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Affiliation(s)
- Chenhao Ge
- Department of Chemistry and Biochemistry University of Arizona Tucson, AZ 85721-0041
| | - Kristina S. Orosz
- Department of Chemistry and Biochemistry University of Arizona Tucson, AZ 85721-0041
| | - Neal R. Armstrong
- Department of Chemistry and Biochemistry University of Arizona Tucson, AZ 85721-0041
| | - S. Scott Saavedra
- Department of Chemistry and Biochemistry University of Arizona Tucson, AZ 85721-0041
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Becucci L, D'Amico M, Cinotti S, Daniele S, Guidelli R. Tethered bilayer lipid micromembranes for single-channel recording: the role of adsorbed and partially fused lipid vesicles. Phys Chem Chem Phys 2011; 13:13341-8. [PMID: 21701758 DOI: 10.1039/c1cp20667b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A mercury-supported bilayer lipid micromembrane was prepared by anchoring a thiolipid monolayer to a mercury cap electrodeposited on a platinum microdisc about 20 μm in diameter; a lipid monolayer was then self-assembled on top of the thiolipid monolayer either by vesicle fusion or by spilling a few drops of a lipid solution in chloroform on the cap and allowing the solvent to evaporate. Single-channel recording following incorporation of the alamethicin channel-forming peptide exhibits quite different features, depending on the procedure followed to form the distal lipid monolayer. The "spilling" procedure, which avoids the formation of adsorbed or partially fused vesicles, yields very sharp single-channel currents lasting only one or two milliseconds. These are ascribed to ionic flux into the hydrophilic spacer moiety of the thiolipid. Conversely, the vesicle-fusion procedure yields much longer single-channel openings analogous to those obtained with conventional bilayer lipid membranes, albeit smaller. This difference in behavior is explained by ascribing the latter single-channel currents to ionic flux into vesicles adsorbed and/or partially fused onto the tethered lipid bilayer, via capacitive coupling.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy.
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Abstract
Tethered bilayer lipid membranes can be used as model platforms to host membrane proteins or membrane-active peptides, which can act as transducers in sensing applications. Here we present the synthesis and characterization of a valinomycin derivative, a depsipeptide that has been functionalized to serve as a redox probe in a lipid bilayer. In addition, we discuss the influence of the molecular structure of the lipid bilayer on its ability to host proteins. By using electrical impedance techniques as well as neutron scattering experiments, a clear correlation between the packing density of the lipids forming the membrane and its ability to host membrane proteins could be shown.
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Kendall JKR, Johnson BRG, Symonds PH, Imperato G, Bushby RJ, Gwyer JD, van Berkel C, Evans SD, Jeuken LJC. Effect of the structure of cholesterol-based tethered bilayer lipid membranes on ionophore activity. Chemphyschem 2010; 11:2191-8. [PMID: 20512836 DOI: 10.1002/cphc.200900917] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Tethered bilayer lipid membranes (tBLM) are formed on 1) pure tether lipid triethyleneoxythiol cholesterol (EO(3)C) or on 2) mixed self-assembled monolayers (SAMs) of EO(3)C and 6-mercaptohexanol (6MH). While EO(3)C is required to form a tBLM with high resistivity, 6MH dilutes the cholesterol content in the lower leaflet of the bilayer forming ionic reservoirs required for submembrane hydration. Here we show that these ionic reservoirs are required for ion transport through gramicidin or valinomycin, most likely due to the thermodynamic requirements of ions to be solvated once transported through the membrane. Unexpectedly, electrochemical impedance spectroscopy (EIS) shows an increase of capacitance upon addition of gramicidin, while addition of valinomycin decreases the membrane resistance in the presence of K(+) ions. We hypothesise that this is due to previously reported phase separation of EO(3)C and 6MH on the surface. This results in ionic reservoirs on the nanometre scale, which are not fully accounted for by the equivalent circuits used to describe the system.
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Affiliation(s)
- James K R Kendall
- School of Physics & Astronomy, University of Leeds, Leeds, LS2 9JT, UK
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26
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Abstract
Tethered bilayer lipid membranes have been shown to be an excellent model system for biological membranes. Coupling of a membrane to a solid supports creates a stable system that is accessible for various surface analytical tools. Good electrical sealing properties also enable the use of the membranes in practical sensing applications. The authors have shown that tethered membranes have extended lifetimes up to several months. Air-stability of the bilayer can be achieved by coating the membrane with a hydrogel. The structure of a monolayer and its stability under applied dc potentials have been investigated by neutron scattering.
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Onishi J, Shirai O, Kano K. Electrochemical Elucidation of the Facilitated Ion Transport Across a Bilayer Lipid Membrane in the Presence of Neutral Carrier Compounds. ELECTROANAL 2010. [DOI: 10.1002/elan.200900481] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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28
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Leitch J, Kunze J, Goddard JD, Schwan AL, Faragher RJ, Naumann R, Knoll W, Dutcher JR, Lipkowski J. In situ PM-IRRAS studies of an archaea analogue thiolipid assembled on a au(111) electrode surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:10354-10363. [PMID: 19499931 DOI: 10.1021/la900907d] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) has been applied to determine the conformation, orientation, and hydration of a monolayer of 2,3-di-O-phytanyl-sn-glycerol-1-tetraethylene glycol-dl-alpha-lipoic acid ester (DPTL) self-assembled at a gold electrode surface. This Archaea analogue thiolipid has been recently employed to build tethered lipid bilayers. By synthesizing DPT(d16)L, a DPTL molecule with a deuterium substituted tetraethylene glycol spacer, it was possible to differentiate the C-H stretch vibrations of the phytanyl chains from the tetraethylene glycol spacer and acquire the characteristic IR spectra for the chains, spacer, and lipoic acid headgroup separately. Our results show that the structure of the monolayer displays remarkable stability in a broad range of electrode potentials and that the phytanyl chains remain in a liquid crystalline state. The tetraethylene glycol chains are coiled, and the IR spectrum for this region shows that it is in the disordered state. The most significant result of this study is the information that in contrast to expectations the spacer region is poorly hydrated. Our results have implications for the design of a tethered lipid membrane based on this thiolipid.
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Affiliation(s)
- Jay Leitch
- Department of Chemistry, University of Guelph, Guelph, Ontario, N1G2W1 Canada
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29
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Becucci L, D'Amico M, Daniele S, Olivotto M, Pozzi A, Guidelli R. A metal-supported biomimetic micromembrane allowing the recording of single-channel activity and of impedance spectra of membrane proteins. Bioelectrochemistry 2009; 78:176-80. [PMID: 19726240 DOI: 10.1016/j.bioelechem.2009.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 08/09/2009] [Accepted: 08/11/2009] [Indexed: 10/20/2022]
Abstract
A novel tethered bilayer lipid micromembrane (tBLmicroM) was prepared and characterized. It consists of a mercury cap electrodeposited on a platinum microelectrode, about 20 microm in diameter. The micromembrane was prepared by tethering to the mercury cap a thiolipid monolayer and by then self-assembling a lipid monolayer on top of it. The thiolipid consisted of a disulfidated tetraoxyethylene hydrophilic spacer covalently linked to two phytanyl chains. Upon incorporating OmpF porin in the tBLmicroM, its single-channel activity was recorded by the patch-clamp technique, and its particular features described. An electrochemical impedance spectrum of the tBLmicroM incorporating OmpF porin is also reported. To the best of our knowledge, this tBLmicroM is the first metal-supported biomimetic micromembrane capable of incorporating non-engineered channel proteins in a functionally active state from their detergent solutions, and of allowing the recording of single-channel activity and of impedance spectra of these proteins via ion translocation into the hydrophilic spacer. The limited spaciousness of the spacer prevents a statistical analysis based on current-amplitude or blockage-time histograms. Nonetheless, the robustness, stability, ease of preparation and disposability of the present tBLmicroM may open the way to the realization of a channel-protein microarray platform allowing a high throughput drug screening.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy.
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30
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Impedance analysis of valinomycin activity in nano-BLMs. Chem Phys Lipids 2009; 160:109-13. [PMID: 19446541 DOI: 10.1016/j.chemphyslip.2009.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 05/06/2009] [Accepted: 05/06/2009] [Indexed: 10/20/2022]
Abstract
Nano-black lipid membranes (nano-BLMs) were obtained by functionalization of highly ordered porous alumina substrates with an average pore diameter of 60nm based on a self-assembled alkanethiol submonolayer followed by spreading of 1,2-diphytanoyl-sn-glycero-3-phosphocholine dissolved in n-decane on the hydrophobic substrate. By means of impedance spectroscopy, we analyzed the influence of the self-assembled alkanethiol submonolayer on the electrical properties of the nano-BLMs as well as their long-term stability. We were able to stably integrate nano-BLMs into a flow through system, which allowed us to readily exchange buffer solutions several times and accounts for mass transport phenomena. The ionophore valinomycin was successfully inserted into nano-BLMs and its transport activity monitored as a function of different potassium and sodium ion concentrations reflecting the specificity of valinomycin for potassium ions.
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31
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Becucci L, Schwan AL, Sheepwash EE, Guidelli R. A new method to evaluate the surface dipole potential of thiol and disulfide self-assembled monolayers and its application to a disulfidated tetraoxyethylene glycol. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:1828-1835. [PMID: 19170650 DOI: 10.1021/la803282w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A procedure to evaluate the surface dipole potential chi of thiol and disulfide self-assembled monolayers (SAMs) is described. The procedure consists of self-assembling the monolayers on a hanging mercury drop electrode and of measuring the charge involved in a progressive expansion of the mercury drop. This measurement is then combined with an estimate of the charge density q experienced by diffuse layer ions, obtained by measuring the diffuse layer capacitance of the SAM at different electrolyte concentrations by electrochemical impedance spectroscopy. These chi measurements, combined with chronocoulometric measurements of the total charge density sigma(M) against potential, indicate that SAMs of tetraoxyethylene glycol-D,L-alpha-lipoic acid ester (TEGL), 2,3-di-O-phytanyl-sn-glycerol-1-tetraoxyethylene glycol-D,L-alpha-lipoic ester (DPTL), and trioxyethyleneoxythiol (EO3) on mercury may undergo a reversal in the surface dipole potential of their polyoxyethylene chain with a change in the interfacial electric field. Moreover, TEGL and EO3 form stable SAMs without electron transfer to the metal, while no such conclusion can be drawn for DPTL.
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Affiliation(s)
- Lucia Becucci
- Department of Chemistry, Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy
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Jadhav SR, Zheng Y, Michael Garavito R, Mark Worden R. Functional characterization of PorB class II porin from Neisseria meningitidis using a tethered bilayer lipid membrane. Biosens Bioelectron 2008; 24:837-41. [DOI: 10.1016/j.bios.2008.07.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/01/2008] [Accepted: 07/04/2008] [Indexed: 11/29/2022]
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34
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Potassium ion transport by gramicidin and valinomycin across a Ag(111)-supported tethered bilayer lipid membrane. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2008.04.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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35
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Robertson JWF, Friedrich MG, Kibrom A, Knoll W, Naumann RLC, Walz D. Modeling Ion Transport in Tethered Bilayer Lipid Membranes. 1. Passive Ion Permeation. J Phys Chem B 2008; 112:10475-82. [DOI: 10.1021/jp800162d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joseph W. F. Robertson
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Biozentrum, University of Basel, Basel, Switzerland
| | - Marcel G. Friedrich
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Biozentrum, University of Basel, Basel, Switzerland
| | - Asmorom Kibrom
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Biozentrum, University of Basel, Basel, Switzerland
| | - Wolfgang Knoll
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Biozentrum, University of Basel, Basel, Switzerland
| | - Renate L. C. Naumann
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Biozentrum, University of Basel, Basel, Switzerland
| | - Dieter Walz
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany, and Biozentrum, University of Basel, Basel, Switzerland
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36
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Jadhav SR, Sui D, Garavito RM, Worden RM. Fabrication of highly insulating tethered bilayer lipid membrane using yeast cell membrane fractions for measuring ion channel activity. J Colloid Interface Sci 2008; 322:465-72. [DOI: 10.1016/j.jcis.2008.02.064] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 02/22/2008] [Accepted: 02/22/2008] [Indexed: 10/22/2022]
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37
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Knoll W, Naumann R, Friedrich M, Robertson JWF, Lösche M, Heinrich F, McGillivray DJ, Schuster B, Gufler PC, Pum D, Sleytr UB. Solid supported lipid membranes: new concepts for the biomimetic functionalization of solid surfaces. Biointerphases 2008; 3:FA125. [PMID: 20408662 PMCID: PMC2876326 DOI: 10.1116/1.2913612] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Surface-layer (S-layer) supported lipid membranes on solid substrates are interfacial architectures mimicking the supramolecular principle of cell envelopes which have been optimized for billions of years of evolution in most extreme habitats. The authors implement this biological construction principle in a variety of layered supramolecular architectures consisting of a stabilizing protein monolayer and a functional phospholipid bilayer for the design and development of new types of solid-supported biomimetic membranes with a considerably extended stability and lifetime-compared to existing platforms-as required for novel types of bioanalytical sensors. First, Langmuir monolayers of lipids at the water/air interface are used as test beds for the characterization of different types of molecules which all interact with the lipid layers in various ways and, hence, are relevant for the control of the structure, stability, and function of supported membranes. As an example, the interaction of S-layer proteins from the bulk phase with a monolayer of a phospholipid synthetically conjugated with a secondary cell wall polymer (SCWP) was studied as a function of the packing density of the lipids in the monolayer. Furthermore, SCWPs were used as a new molecular construction element. The exploitation of a specific lectin-type bond between the N-terminal part of selected S-layer proteins and a variety of glycans allowed for the buildup of supramolecular assemblies and thus functional membranes with a further increased stability. Next, S-layer proteins were self-assembled and characterized by the surface-sensitive techniques, surface plasmon resonance spectroscopy and quartz crystal microbalance with dissipation monitoring. The substrates were either planar gold or silicon dioxide sensor surfaces. The assembly of S-layer proteins from solution to solid substrates could nicely be followed in-situ and in real time. As a next step toward S-layer supported bilayer membranes, the authors characterized various architectures based on lipid molecules that were modified by a flexible spacer separating the amphiphiles from the anchor group that allows for a covalent coupling of the lipid to a solid support, e.g., using thiols for Au substrates. Impedance spectroscopy confirmed the excellent charge barrier properties of these constructs with a high electrical resistance. Structural details of various types of these tethered bimolecular lipid membranes were studied by using neutron reflectometry. Finally, first attempts are reported to develop a code based on a SPICE network analysis program which is suitable for the quantitative analysis of the transient and steady-state currents passing through these membranes upon the application of a potential gradient.
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Affiliation(s)
- W Knoll
- Max Planck Institute for Polymer Research, Ackermannweg 10, D-55021 Mainz, Germany.
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38
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Alvarez PE, Gervasi CA, Vallejo AE. Impedance analysis of ion transport through supported lipid membranes doped with ionophores: a new kinetic approach. J Biol Phys 2008; 33:421-31. [PMID: 19669528 DOI: 10.1007/s10867-008-9072-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 04/03/2008] [Indexed: 12/01/2022] Open
Abstract
Kinetics of facilitated ion transport through planar bilayer membranes are normally analyzed by electrical conductance methods. The additional use of electrical relaxation techniques, such as voltage jump, is necessary to evaluate individual rate constants. Although electrochemical impedance spectroscopy is recognized as the most powerful of the available electric relaxation techniques, it has rarely been used in connection with these kinetic studies. According to the new approach presented in this work, three steps were followed. First, a kinetic model was proposed that has the distinct quality of being general, i.e., it properly describes both carrier and channel mechanisms of ion transport. Second, the state equations for steady-state and for impedance experiments were derived, exhibiting the input-output representation pertaining to the model's structure. With the application of a method based on the similarity transformation approach, it was possible to check that the proposed mechanism is distinguishable, i.e., no other model with a different structure exhibits the same input-output behavior for any input as the original. Additionally, the method allowed us to check whether the proposed model is globally identifiable (i.e., whether there is a single set of fit parameters for the model) when analyzed in terms of its impedance response. Thus, our model does not represent a theoretical interpretation of the experimental impedance but rather constitutes the prerequisite to select this type of experiment in order to obtain optimal kinetic identification of the system. Finally, impedance measurements were performed and the results were fitted to the proposed theoretical model in order to obtain the kinetic parameters of the system. The successful application of this approach is exemplified with results obtained for valinomycin-K(+) in lipid bilayers supported onto gold substrates, i.e., an arrangement capable of emulating biological membranes.
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Affiliation(s)
- P E Alvarez
- Instituto de Física, Facultad de Bioquímica, Química y Farmacia, UNT, Tucumán, Argentina
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39
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In situ monitoring of the catalytic activity of cytochrome C oxidase in a biomimetic architecture. Biophys J 2008; 95:1500-10. [PMID: 18441024 DOI: 10.1529/biophysj.107.122747] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytochrome c oxidase (CcO) from Paracoccus denitrificans was immobilized in a strict orientation via a his-tag attached to subunit I on a gold film and reconstituted in situ into a protein-tethered bilayer lipid membrane. In this orientation, the cytochrome c (cyt c) binding site is directed away from the electrode pointing to the outer side of the protein-tethered bilayer lipid membrane architecture. The CcO can thus be activated by cyt c under aerobic conditions. Catalytic activity was monitored by impedance spectroscopy, as well as cyclic voltammetry. Cathodic and anodic currents of the CcO with cyt c added to the bulk solution were shown to increase under aerobic compared to anaerobic conditions. Catalytic activity was considered in terms of repeated electrochemical oxidation/reduction of the CcO/cyt c complex in the presence of oxygen. The communication of cyt c bound to the CcO with the electrode is discussed in terms of a hopping mechanism through the redox sites of the enzyme. Simulations supporting this hypothesis are included.
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Grieshaber D, MacKenzie R, Vörös J, Reimhult E. Electrochemical Biosensors - Sensor Principles and Architectures. SENSORS (BASEL, SWITZERLAND) 2008; 8:1400-1458. [PMID: 27879772 PMCID: PMC3663003 DOI: 10.3390/s80314000] [Citation(s) in RCA: 752] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Accepted: 01/28/2008] [Indexed: 11/16/2022]
Abstract
Quantification of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. However, converting the biological information to an easily processed electronic signal is challenging due to the complexity of connecting an electronic device directly to a biological environment. Electrochemical biosensors provide an attractive means to analyze the content of a biological sample due to the direct conversion of a biological event to an electronic signal. Over the past decades several sensing concepts and related devices have been developed. In this review, the most common traditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, and various field-effect transistor based methods are presented along with selected promising novel approaches, such as nanowire or magnetic nanoparticle-based biosensing. Additional measurement techniques, which have been shown useful in combination with electrochemical detection, are also summarized, such as the electrochemical versions of surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry, quartz crystal microbalance, and scanning probe microscopy. The signal transduction and the general performance of electrochemical sensors are often determined by the surface architectures that connect the sensing element to the biological sample at the nanometer scale. The most common surface modification techniques, the various electrochemical transduction mechanisms, and the choice of the recognition receptor molecules all influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches, such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymes into vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities for signal amplification. In particular, this review highlights the importance of the precise control over the delicate interplay between surface nano-architectures, surface functionalization and the chosen sensor transducer principle, as well as the usefulness of complementary characterization tools to interpret and to optimize the sensor response.
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Affiliation(s)
- Dorothee Grieshaber
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland.
| | - Robert MacKenzie
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland.
| | - Janos Vörös
- Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland.
| | - Erik Reimhult
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland.
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Vockenroth IK, Fine D, Dodobalapur A, Jenkins ATA, Köper I. Tethered bilayer lipid membranes with giga-ohm resistances. Electrochem commun 2008. [DOI: 10.1016/j.elecom.2007.12.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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43
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Reimhult E, Kumar K. Membrane biosensor platforms using nano- and microporous supports. Trends Biotechnol 2008; 26:82-9. [DOI: 10.1016/j.tibtech.2007.11.004] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 11/08/2007] [Accepted: 11/08/2007] [Indexed: 10/22/2022]
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44
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Peptid-tethered bilayer lipid membranes and their interaction with Amyloid ß-peptide. Biointerphases 2007; 2:151-8. [DOI: 10.1116/1.2804746] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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45
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Probing DNA hybridization in thiolipid monolayers by means of impedance spectroscopy. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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46
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Rossi C, Chopineau J. Biomimetic tethered lipid membranes designed for membrane-protein interaction studies. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2007; 36:955-65. [PMID: 17611752 DOI: 10.1007/s00249-007-0202-y] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 06/07/2007] [Accepted: 06/11/2007] [Indexed: 11/26/2022]
Abstract
The complexity of the biological membranes restricts their direct investigation at the nanoscale. Lipid bilayer membranes have been developed as a model of biological membranes in order to allow the interaction and insertion of peptides and membrane proteins in a functional manner. Promising models have been developed in the past two decades and tethered bilayer design traduces constant improvement of membrane models. The formation of protein free solid tethered membranes can be achieved by direct vesicle fusion, Langmuir-Blodgett, Langmuir-Schaffer transfers, self assembly of various building blocks such as thiol on gold, silane on quartz, grafting of polymers, as well as ligand receptor recognition. In this review, the current state of different tethered bilayer membrane will be described. We will focus on critical analysis of the main advantages/drawbacks of each kind of model construction and their ability to allow protein incorporation in non-denaturing conditions. Some of the current drawbacks encountered in these biomimetic models can be overcome using an innovative tethered bilayer design based on a reliable and fast formation method. The successful protein incorporation of the Adenylate Cyclase produced by Bordetella pertussis and the voltage dependent anion channel (VDAC) was demonstrated on this model.
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Affiliation(s)
- Claire Rossi
- Max-Planck Institut für Polymerforschung, Ackermannweg 10, 55128, Mainz, Germany
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47
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Becucci L, Guidelli R, Karim CB, Thomas DD, Veglia G. An electrochemical investigation of sarcolipin reconstituted into a mercury-supported lipid bilayer. Biophys J 2007; 93:2678-87. [PMID: 17586575 PMCID: PMC1989701 DOI: 10.1529/biophysj.107.109280] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sarcolipin was incorporated into a lipid bilayer anchored to a mercury electrode through a hydrophilic tetraethyleneoxy chain. The behavior of this tethered bilayer lipid membrane incorporating sarcolipin was investigated by electrochemical impedance spectroscopy and by recording charge versus time curves after potential jumps. When the transmembrane potential starts to become negative on the trans side, evidence is provided that sarcolipin aggregates into ion-conducting pores. Over the range of physiological transmembrane potentials, these pores are permeable to small inorganic anions such as chloride, phosphate, or sulfate but impermeable to inorganic cations such as Na+ and K+. Only at transmembrane potentials more negative than approximately -150 mV on the trans side do sarcolipin channels allow the translocation of the latter cations. A tentative relationship between this property of sarcolipin and its regulatory function on Ca-ATPase of sarcoplasmic reticulum is proposed.
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Affiliation(s)
- Lucia Becucci
- Chemistry Department, Florence University, 50019 Florence, Italy
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48
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Dorvel BR, Keizer HM, Fine D, Vuorinen J, Dodabalapur A, Duran RS. Formation of tethered bilayer lipid membranes on gold surfaces: QCM-Z and AFM study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:7344-55. [PMID: 17503853 DOI: 10.1021/la0610396] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Recently, tethered bilayer lipid membranes (tBLMs) have shown high potential as biomimetic systems due to their high stability and electrical properties, and have been used in applications ranging from membrane protein incorporation to biosensors. However, the kinetics of their formation remains largely uninvestigated. By using quartz crystal microbalance with impedance analysis (QCM-Z), we were able to monitor both the kinetics and viscoelastic properties of tether adsorption and vesicle fusion. Formation of the tether monolayer was shown to follow pseudo-first-order Langmuir kinetics with association and dissociation rate constants of 21.7 M-1 s(-1) and 7.43 x 10-6 s(-1), respectively. Moreover, the QCM-Z results indicate a rigid layer at the height of deposition, which then undergoes swelling as indicated by AFM. The deposition of vesicles to the tether layer also followed pseudo-first-order Langmuir kinetics with observed rate constants of 5.58 x 10(-2) and 2.41 x 10-2 s(-1) in water and buffer, respectively. Differential analysis of the QCM-Z data indicated deposition to be the fast kinetic step, with the rate-limiting steps being water release and fusion. Atomic force microscopy pictures taken complement the QCM-Z data, showing the major stages of tether adsorption and vesicle fusion, while providing a road map to successful tBLM formation.
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Affiliation(s)
- Brian R Dorvel
- George and Josephine Butler Polymer Laboratory, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
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Vallejo A, Gervasi C. EIS studies of valinomycin-mediated K+ transport through supported lipid bilayers. J Electroanal Chem (Lausanne) 2007. [DOI: 10.1016/j.jelechem.2007.01.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Vockenroth IK, Atanasova PP, Long JR, Jenkins ATA, Knoll W, Köper I. Functional incorporation of the pore forming segment of AChR M2 into tethered bilayer lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1114-20. [PMID: 17368423 DOI: 10.1016/j.bbamem.2007.02.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 02/06/2007] [Accepted: 02/06/2007] [Indexed: 10/23/2022]
Abstract
Tethered bilayer lipid membranes (tBLMs) are robust and flexible model platforms for the investigation of various membrane related processes. They are especially suited to study the incorporation and function of ion channel proteins, where a high background resistance of the membrane is essential. Synthetic M2 peptides, analogues of the transmembrane fragment of the acetylcholine receptor, could be incorporated into two different membrane architectures. The functional reconstitution and the formation of a conducting pore are shown by electrochemical impedance spectroscopy (EIS). The pore is selective for small monovalent cations, while bulky ions cannot pass. This is a significant step towards a novel biosensing approach. We envision a device, where a stable and insulating membrane would be attached to an electronic read-out unit and embedded proteins would serve as actual sensing units.
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