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Köhler S, Fragneto G, Alcaraz JP, Nelson A, Martin DK, Maccarini M. Nanostructural Characterization of Cardiolipin-Containing Tethered Lipid Bilayers Adsorbed on Gold and Silicon Substrates for Protein Incorporation. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:8908-8923. [PMID: 34286589 DOI: 10.1021/acs.langmuir.1c00119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A key to the development of lipid membrane-based devices is a fundamental understanding of how the molecular structure of the lipid bilayer membrane is influenced by the type of lipids used to build the membrane. This is particularly important when membrane proteins are included in these devices since the precise lipid environment affects the ability to incorporate membrane proteins and their functionality. Here, we used neutron reflectometry to investigate the structure of tethered bilayer lipid membranes and to characterize the incorporation of the NhaA sodium proton exchanger in the bilayer. The lipid membranes were composed of two lipids, dioleoyl phosphatidylcholine and cardiolipin, and were adsorbed on gold and silicon substrates using two different tethering architectures based on functionalized oligoethylene glycol molecules of different lengths. In all of the investigated samples, the addition of cardiolipin caused distinct structural rearrangement including crowding of ethylene glycol groups of the tethering molecules in the inner head region and a thinning of the lipid tail region. The incorporation of NhaA in the tethered bilayers following two different protocols is quantified, and the way protein incorporation modulates the structural properties of these membranes is detailed.
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Affiliation(s)
- Sebastian Köhler
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC/SyNaBi, 38000 Grenoble, France
- Institut Laue-Langevin, 38042 Grenoble, France
| | | | - Jean-Pierre Alcaraz
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC/SyNaBi, 38000 Grenoble, France
| | - Andrew Nelson
- ANSTO-Sydney, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Donald K Martin
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC/SyNaBi, 38000 Grenoble, France
| | - Marco Maccarini
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC/SyNaBi, 38000 Grenoble, France
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2
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Laftsoglou T, Jeuken LJC. Supramolecular electrode assemblies for bioelectrochemistry. Chem Commun (Camb) 2017; 53:3801-3809. [PMID: 28317998 PMCID: PMC5436043 DOI: 10.1039/c7cc01154g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/14/2017] [Indexed: 12/03/2022]
Abstract
For more than three decades, the field of bioelectrochemistry has provided novel insights into the catalytic mechanisms of enzymes, the principles that govern biological electron transfer, and has elucidated the basic principles for bioelectrocatalytic systems. Progress in biochemistry, bionanotechnology, and our ever increasing ability to control the chemistry and structure of electrode surfaces has enabled the study of ever more complex systems with bioelectrochemistry. This feature article highlights developments over the last decade, where supramolecular approaches have been employed to develop electrode assemblies that increase enzyme loading on the electrode or create more biocompatible environments for membrane enzymes. Two approaches are particularly highlighted: the use of layer-by-layer assembly, and the modification of electrodes with planar lipid membranes.
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Affiliation(s)
- Theodoros Laftsoglou
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, Leeds, UK.
| | - Lars J C Jeuken
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, LS2 9JT, Leeds, UK.
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Andersson J, Köper I. Tethered and Polymer Supported Bilayer Lipid Membranes: Structure and Function. MEMBRANES 2016; 6:E30. [PMID: 27249006 PMCID: PMC4931525 DOI: 10.3390/membranes6020030] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 05/24/2016] [Accepted: 05/25/2016] [Indexed: 11/30/2022]
Abstract
Solid supported bilayer lipid membranes are model systems to mimic natural cell membranes in order to understand structural and functional properties of such systems. The use of a model system allows for the use of a wide variety of analytical tools including atomic force microscopy, impedance spectroscopy, neutron reflectometry, and surface plasmon resonance spectroscopy. Among the large number of different types of model membranes polymer-supported and tethered lipid bilayers have been shown to be versatile and useful systems. Both systems consist of a lipid bilayer, which is de-coupled from an underlying support by a spacer cushion. Both systems will be reviewed, with an emphasis on the effect that the spacer moiety has on the bilayer properties.
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Affiliation(s)
- Jakob Andersson
- Flinders Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide SA 5001, Australia.
| | - Ingo Köper
- Flinders Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Adelaide SA 5001, Australia.
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4
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Lipid bilayers supported on bare and modified gold – Formation, characterization and relevance of lipid rafts. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2013.07.117] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Liu X, Li L, Mason AJ. High-throughput impedance spectroscopy biosensor array chip. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130107. [PMID: 24567474 DOI: 10.1098/rsta.2013.0107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Impedance spectroscopy is a powerful tool for characterizing materials that exhibit a frequency dependent behaviour to an applied electric field. This paper introduces a fully integrated multi-channel impedance extraction circuit that can both generate AC stimulus signals over a broad frequency range and also measure and digitize the real and imaginary components of the impedance response. The circuit was fabricated in a 0.5 μm complementary metal-oxide semiconductor. Tailored for cellular membrane interface characterization, the signal generator produces sinusoidal waves from 10 mHz to 10 kHz. To suit a variety of applications, the impedance extraction circuit provides a programmable current measurement range from 100 pA to 100 nA with a measured resolution of approximately 100 fA. Occupying only 0.045 mm(2) per measurement channel, the circuit is compact enough to include nearly 200 channels in a 3×3 mm(2) die area.
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Affiliation(s)
- Xiaowen Liu
- Department of Electrical and Computer Engineering, Michigan State University, , East Lansing, MI, USA
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A Comparative Study of α-Hemolysin Expression in Supported Lipid Bilayers of Synthetic and Enriched Complex Bacterial Lipid. BIONANOSCIENCE 2014. [DOI: 10.1007/s12668-014-0127-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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7
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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: 22] [Impact Index Per Article: 2.0] [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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Budvytyte R, Valincius G, Niaura G, Voiciuk V, Mickevicius M, Stauffer H, Goh HZ, Shekhar P, Heinrich F, Shenoy S, Lösche M, Vanderah DJ. Structure and properties of tethered bilayer lipid membranes with unsaturated anchor molecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:8645-56. [PMID: 23745652 PMCID: PMC3753044 DOI: 10.1021/la401132c] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The self-assembled monolayers (SAMs) of new lipidic anchor molecule HC18 [Z-20-(Z-octadec-9-enyloxy)-3,6,9,12,15,18,22-heptaoxatetracont-31-ene-1-thiol] and mixed HC18/β-mercaptoethanol (βME) SAMs were studied by spectroscopic ellipsometry, contact angle measurements, reflection-absorption infrared spectroscopy, and electrochemical impedance spectroscopy (EIS) and were evaluated in tethered bilayer lipid membranes (tBLMs). Our data indicate that HC18, containing a double bond in the alkyl segments, forms highly disordered SAMs up to anchor/βME molar fraction ratios of 80/20 and result in tBLMs that exhibit higher lipid diffusion coefficients relative to those of previous anchor compounds with saturated alkyl chains, as determined by fluorescence correlation spectroscopy. EIS data shows the HC18 tBLMs, completed by rapid solvent exchange or vesicle fusion, form more easily than with saturated lipidic anchors, exhibit excellent electrical insulating properties indicating low defect densities, and readily incorporate the pore-forming toxin α-hemolysin. Neutron reflectivity measurements on HC18 tBLMs confirm the formation of complete tBLMs, even at low tether compositions and high ionic lipid compositions. Our data indicate that HC18 results in tBLMs with improved physical properties for the incorporation of integral membrane proteins (IMPs) and that 80% HC18 tBLMs appear to be optimal for practical applications such as biosensors where high electrical insulation and IMP/peptide reconstitution are imperative.
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Affiliation(s)
- Rima Budvytyte
- Institute of Biochemistry, Vilnius University, Vilnius, LT-08662, Lithuania
| | - Gintaras Valincius
- Institute of Biochemistry, Vilnius University, Vilnius, LT-08662, Lithuania
| | - Gediminas Niaura
- Institute of Biochemistry, Vilnius University, Vilnius, LT-08662, Lithuania
| | - Vladislava Voiciuk
- Institute of Biochemistry, Vilnius University, Vilnius, LT-08662, Lithuania
| | | | - Hilary Stauffer
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Hood College, Frederick, MD 21701
| | - Haw-Zan Goh
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
| | | | - Frank Heinrich
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - Siddharth Shenoy
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Mathias Lösche
- Physics Department, Carnegie Mellon University, Pittsburgh, PA 15213
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - David J. Vanderah
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899
- Institute for Bioscience and Biotechnology Research, Rockville, MD 20850
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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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10
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Jackman JA, Cho NJ. Model membrane platforms for biomedicine: case study on antiviral drug development. Biointerphases 2012; 7:18. [PMID: 22589061 PMCID: PMC7099340 DOI: 10.1007/s13758-011-0018-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 12/29/2011] [Indexed: 01/28/2023] Open
Abstract
As one of the most important interfaces in cellular systems, biological membranes have essential functions in many activities such as cellular protection and signaling. Beyond their direct functions, they also serve as scaffolds to support the association of proteins involved in structural support, adhesion, and transport. Unfortunately, biological processes sometimes malfunction and require therapeutic intervention. For those processes which occur within or upon membranes, it is oftentimes difficult to study the mechanism in a biologically relevant, membranous environment. Therefore, the identification of direct therapeutic targets is challenging. In order to overcome this barrier, engineering strategies offer a new approach to interrogate biological activities at membrane interfaces by analyzing them through the principles of the interfacial sciences. Since membranes are complex biological interfaces, the development of simplified model systems which mimic important properties of membranes can enable fundamental characterization of interaction parameters for such processes. We have selected the hepatitis C virus (HCV) as a model viral pathogen to demonstrate how model membrane platforms can aid antiviral drug discovery and development. Responsible for generating the genomic diversity that makes treating HCV infection so difficult, viral replication represents an ideal step in the virus life cycle for therapeutic intervention. To target HCV genome replication, the interaction of viral proteins with model membrane platforms has served as a useful strategy for target identification and characterization. In this review article, we demonstrate how engineering approaches have led to the discovery of a new functional activity encoded within the HCV nonstructural 5A protein. Specifically, its N-terminal amphipathic, α-helix (AH) can rupture lipid vesicles in a size-dependent manner. While this activity has a number of exciting biotechnology and biomedical applications, arguably the most promising one is in antiviral medicine. Based on the similarities between lipid vesicles and the lipid envelopes of virus particles, experimental findings from model membrane platforms led to the prediction that a range of medically important viruses might be susceptible to rupturing treatment with synthetic AH peptide. This hypothesis was tested and validated by molecular virology studies. Broad-spectrum antiviral activity of the AH peptide has been identified against HCV, HIV, herpes simplex virus, and dengue virus, and many more deadly pathogens. As a result, the AH peptide is the first in class of broad-spectrum, lipid envelope-rupturing antiviral agents, and has entered the drug pipeline. In summary, engineering strategies break down complex biological systems into simplified biomimetic models that recapitulate the most important parameters. This approach is particularly advantageous for membrane-associated biological processes because model membrane platforms provide more direct characterization of target interactions than is possible with other methods. Consequently, model membrane platforms hold great promise for solving important biomedical problems and speeding up the translation of biological knowledge into clinical applications.
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Affiliation(s)
- Joshua A. Jackman
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798 Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, Singapore, 637553 Singapore
| | - Nam-Joon Cho
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798 Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 637551 Singapore
- Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, Singapore, 637553 Singapore
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University, 269 Campus Drive, Stanford, CA 94305 USA
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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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12
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Campos R, Kataky R. Electron Transport in Supported and Tethered Lipid Bilayers Modified with Bioelectroactive Molecules. J Phys Chem B 2012; 116:3909-17. [DOI: 10.1021/jp209772u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rui Campos
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom
| | - Ritu Kataky
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, United Kingdom
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Qureshi WA, Mason AJ. CMOS Amperometric Instrumentation and Packaging for Biosensor Array Applications. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2011; 5:439-448. [PMID: 23852176 DOI: 10.1109/tbcas.2011.2171339] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
An integrated CMOS amperometric instrument with on-chip electrodes and packaging for biosensor arrays is presented. The mixed-signal integrated circuit supports a variety of electrochemical measurement techniques including linear sweep, constant potential, cyclic and pulse voltammetry. Implemented in 0.5 μm CMOS, the 3 × mm(2) chip dissipates 22.5 mW for a 200 kHz clock. The highly programmable chip provides a wide range of user-controlled stimulus rate and amplitude settings with a maximum scan range of 2 V and scan rates between 1 mV/sec and 400 V/sec. The amperometric readout circuit provides ±500 fA linear resolution and supports inputs up to ±47 μA. A 2 × 2 gold electrode array was fabricated on the surface of the CMOS instrumentation chip. An all-parylene packaging scheme was developed for compatibility with liquid test environments as well as a harsh piranha electrode cleaning process. The chip was tested using cyclic voltammetry of different concentrations of potassium ferricyanide at 100 mV/s and 200 mV/s, and results were identical to measurements using commercial instruments.
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15
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Schrems A, Kibrom A, Küpcü S, Kiene E, Sleytr UB, Schuster B. Bilayer lipid membrane formation on a chemically modified S-layer lattice. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:3731-3738. [PMID: 21401053 DOI: 10.1021/la104238e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The present paper describes the generation of a biomimetic model lipid membrane on bacterial surface (S-)layer which covered the entire surface of various sensors. The S-layer lattice allows one to be independent from the underlying solid material and provides a biological surface and anchoring structure for lipid membranes. S-layer proteins were chemically modified via binding of two amine-terminated phospholipids. Subsequently, a bimolecular lipid membrane anchored to the previously generated viscoelastic lipid monolayer was generated by the rapid solvent exchange technique. Characterization of the intermediate (monolayer) and final membrane structures (bilayer) was performed by imaging, surface-sensitive, and electrochemical techniques. This bilayer lipid membrane generated on an S-layer lattice revealed a thickness of ∼6 nm and constitutes a stable supported model membrane system with highly isolating properties showing a membrane resistance of 8.5 MΩ × cm(2).
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Affiliation(s)
- A Schrems
- Department for NanoBiotechnology, University of Natural Resources and Life Sciences, Vienna (BOKU), Muthgasse 11, 1190 Vienna, Austria
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16
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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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17
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Largueze JB, Kirat KE, Morandat S. Preparation of an electrochemical biosensor based on lipid membranes in nanoporous alumina. Colloids Surf B Biointerfaces 2010; 79:33-40. [DOI: 10.1016/j.colsurfb.2010.03.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 03/17/2010] [Accepted: 03/17/2010] [Indexed: 12/25/2022]
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Greiner AJ, Pillman HA, Worden RM, Blanchard GJ, Ofoli RY. Effect of hydrogen bonding on the rotational and translational dynamics of a headgroup-bound chromophore in bilayer lipid membranes. J Phys Chem B 2009; 113:13263-8. [PMID: 19761197 DOI: 10.1021/jp9057862] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have studied the interactions of the chromophore 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-7-nitro-2-1,3-benzoxadiazol-4-yl (18:1 NBD-PE) imbedded in the headgroup region of bilayer lipid membranes consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DOPG). We have examined the molecular and mesoscale dynamics of the chromophore using time-correlated single photon counting (TCSPC) to measure rotational diffusion dynamics in lipid vesicles and fluorescence recovery after pattern photobleaching (FRAPP) to determine translational diffusion coefficients and mobile fractions in supported lipid bilayers. TCSPC data reveal that chromophore rotational diffusion rates in DOPG vesicles are statistically the same as in DOPC and mixed DOPC/DOPG vesicles, suggesting that the NBD-PE chromophore does not interact strongly with the headgroup region of these bilayers; however, FRAPP experiments show that lateral diffusion is statistically lower in mixed DOPC/DOPG-supported bilayers than in DOPC-supported bilayers. These results suggest that bilayers containing DOPG likely undergo interlipid headgroup hydrogen bonding interactions that suppress translational diffusion.
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Affiliation(s)
- Aaron J Greiner
- Department of Chemical Engineering and Materials Science and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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19
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Hassler BL, Worden RM, Mason AJ. Amperometric electrochemical microsystem for a miniaturized protein biosensor array. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2009; 3:160-168. [PMID: 23853217 DOI: 10.1109/tbcas.2009.2015650] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Protein-based bioelectrochemical interfaces offer great potential for rapid detection, continuous use, and miniaturized sensor arrays. This paper introduces a microsystem platform that enables multiple bioelectrochemical interfaces to be interrogated simultaneously by an onchip amperometric readout system. A post-complementary metal-oxide semiconductor (CMOS) fabrication procedure is described that permits the formation of planar electrode arrays and self assembly of biosensor interfaces on the electrodes. The onchip, 0.5-mum CMOS readout electronics include a compact potentiostat that supports a very broad range of input currents-6 pA to 10 muA-to accommodate diverse biosensor interfaces. The 2.3 times 2.2-mm chip operates from a 5-V supply at 0.6 mA. A prototype electrochemical sensor platform, including an onchip potentiostat and miniaturized biosensor array, was characterized by using cyclic voltammetry. The linear relationship between the oxidization peak values and the concentrations of target analytes in the solution verifies functionality of the system and demonstrates the potential for future implementations of this platform in high sensitivity, low cost, and onchip protein-based sensor arrays.
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Characterization of cytochrome bo3 activity in a native-like surface-tethered membrane. Biochem J 2009; 417:555-60. [PMID: 18821852 DOI: 10.1042/bj20081345] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have developed a simple native-like surface-tethered membrane system to investigate the activity of cbo(3) (cytochrome bo(3)), a terminal oxidase in Escherichia coli. The tethered membranes consist of E. coli inner-membrane extracts mixed with additional E. coli lipids containing various amounts of the cbo(3) substrate UQ-10 (ubiquinol-10). Tethered membranes are formed by self-assembly from vesicles on to gold electrodes functionalized with cholesterol derivatives. cbo(3) activity was monitored using CV (cyclic voltammetry) with electron transfer to cbo(3) mediated by UQ-10. The apparent K(m) for oxygen with this system is 1.1+/-0.4 microM, in good agreement with values reported in the literature for whole-cell experiments and for purified cbo(3). Increasing the concentration of lipophilic UQ-10 in the membrane leads to an increase in cbo(3) activity. The activity of cbo(3) with long-chain ubiquinones appears to be different from previous reports using short-chain substrate analogues such as UQ-1 in that typical Michaelis-Menten kinetics are not observed using UQ-10. This native-like membrane model thus provides new insights into the interaction of transmembrane enzymes with hydrophobic substrates which contrasts with studies using hydrophilic UQ analogues.
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Current awareness on yeast. Yeast 2008. [DOI: 10.1002/yea.1559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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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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