1
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Huang Y, Fuller G, Chandran Suja V. Physicochemical characteristics of droplet interface bilayers. Adv Colloid Interface Sci 2022; 304:102666. [PMID: 35429720 DOI: 10.1016/j.cis.2022.102666] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 11/01/2022]
Abstract
Droplet interface bilayer (DIB) is a lipid bilayer formed when two lipid monolayer-coated aqueous droplets are brought in contact within an oil phase. DIBs, especially post functionalization, are a facile model system to study the biophysics of the cell membrane. Continued advances in enhancing and functionalizing DIBs to be a faithful cell membrane mimetic requires a deep understanding of the physicochemical characteristics of droplet interface bilayers. In this review, we provide a comprehensive overview of the current scientific understanding of DIB characteristics starting with the key experimental frameworks for DIB generation, visualization and functionalization. Subsequently we report experimentally measured physical, electrical and transport characteristics of DIBs across physiologically relevant lipids. Advances in simulations and mathematical modelling of DIBs are also discussed, with an emphasis on revealing principles governing the key physicochemical characteristics. Finally, we conclude the review with important outstanding questions in the field.
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2
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Development of an automated system to measure ion channel currents using a surface-modified gold probe. Sci Rep 2021; 11:17934. [PMID: 34504175 PMCID: PMC8429628 DOI: 10.1038/s41598-021-97237-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 08/18/2021] [Indexed: 11/08/2022] Open
Abstract
Artificial lipid bilayer single-channel recording technique has been employed to determine the biophysical and pharmacological properties of various ion channels. However, its measurement efficiency is very low, as it requires two time-consuming processes: preparation of lipid bilayer membranes and incorporation of ion channels into the membranes. In order to address these problems, we previously developed a technique based on hydrophilically modified gold probes on which are immobilized ion channels that can be promptly incorporated into the bilayer membrane at the same time as the membrane is formed on the probes' hydrophilic area. Here, we improved further this technique by optimizing the gold probe and developed an automated channel current measurement system. We found that use of probes with rounded tips enhanced the efficiency of channel current measurements, and introducing a hydrophobic area on the probe surface, beside the hydrophilic one, further increased measurement efficiency by boosting membrane stability. Moreover, we developed an automated measurement system using the optimized probes; it enabled us to automatically measure channel currents and analyze the effects of a blocker on channel activity. Our study will contribute to the development of high-throughput devices to identify drug candidates affecting ion channel activity.
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3
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Hirano M, Yamamoto D, Asakura M, Hayakawa T, Mise S, Matsumoto A, Ide T. A Lipid Bilayer Formed on a Hydrogel Bead for Single Ion Channel Recordings. MICROMACHINES 2020; 11:mi11121070. [PMID: 33271761 PMCID: PMC7759777 DOI: 10.3390/mi11121070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 11/28/2020] [Accepted: 11/29/2020] [Indexed: 02/05/2023]
Abstract
Ion channel proteins play important roles in various cell functions, making them attractive drug targets. Artificial lipid bilayer recording is a technique used to measure the ion transport activities of channel proteins with high sensitivity and accuracy. However, the measurement efficiency is low. In order to improve the efficiency, we developed a method that allows us to form bilayers on a hydrogel bead and record channel currents promptly. We tested our system by measuring the activities of various types of channels, including gramicidin, alamethicin, α-hemolysin, a voltage-dependent anion channel 1 (VDAC1), a voltage- and calcium-activated large conductance potassium channel (BK channel), and a potassium channel from Streptomyces lividans (KcsA channel). We confirmed the ability for enhanced measurement efficiency and measurement system miniaturizion.
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Affiliation(s)
- Minako Hirano
- Bio Photonics Laboratory, The Graduate School for the Creation of New Photonics Industries, Shizuoka 431-1202, Japan;
| | - Daiki Yamamoto
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, Okayama 700-8530, Japan; (D.Y.); (M.A.); (T.H.)
| | - Mami Asakura
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, Okayama 700-8530, Japan; (D.Y.); (M.A.); (T.H.)
| | - Tohru Hayakawa
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, Okayama 700-8530, Japan; (D.Y.); (M.A.); (T.H.)
| | - Shintaro Mise
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan; (S.M.); (A.M.)
| | - Akinobu Matsumoto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan; (S.M.); (A.M.)
| | - Toru Ide
- Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, Okayama 700-8530, Japan; (D.Y.); (M.A.); (T.H.)
- Correspondence: ; Tel.: +81-86-251-8203
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4
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Recent Advances in Droplet-based Microfluidic Technologies for Biochemistry and Molecular Biology. MICROMACHINES 2019; 10:mi10060412. [PMID: 31226819 PMCID: PMC6631694 DOI: 10.3390/mi10060412] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/16/2019] [Accepted: 06/18/2019] [Indexed: 12/16/2022]
Abstract
Recently, droplet-based microfluidic systems have been widely used in various biochemical and molecular biological assays. Since this platform technique allows manipulation of large amounts of data and also provides absolute accuracy in comparison to conventional bioanalytical approaches, over the last decade a range of basic biochemical and molecular biological operations have been transferred to drop-based microfluidic formats. In this review, we introduce recent advances and examples of droplet-based microfluidic techniques that have been applied in biochemistry and molecular biology research including genomics, proteomics and cellomics. Their advantages and weaknesses in various applications are also comprehensively discussed here. The purpose of this review is to provide a new point of view and current status in droplet-based microfluidics to biochemists and molecular biologists. We hope that this review will accelerate communications between researchers who are working in droplet-based microfluidics, biochemistry and molecular biology.
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5
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Friddin MS, Elani Y, Trantidou T, Ces O. New Directions for Artificial Cells Using Prototyped Biosystems. Anal Chem 2019; 91:4921-4928. [PMID: 30841694 DOI: 10.1021/acs.analchem.8b04885] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Microfluidics has has enabled the generation of a range of single compartment and multicompartment vesicles and bilayer-delineated droplets that can be assembled in 2D and 3D. These model systems are becoming increasingly used as artificial cell chassis and as biomimetic constructs for assembling tissue models, engineering therapeutic delivery systems, and screening drugs. One bottleneck in developing this technology is the time, expertise, and equipment required for device fabrication. This has led to interest across the microfluidics community in using rapid prototyping to engineer microfluidic devices from computer-aided-design (CAD) drawings. We highlight how this rapid-prototyping revolution is transforming the fabrication of microfluidic devices for artificial cell construction in bottom-up synthetic biology. We provide an outline of the current landscape and present how advances in the field may give rise to the next generation of multifunctional biodevices, particularly with Industry 4.0 on the horizon. Successfully developing this technology and making it open-source could pave the way for a new generation of citizen-led science, fueling the possibility that the next multibillion-dollar start-up could emerge from an attic or a basement.
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Affiliation(s)
- Mark S Friddin
- Department of Chemistry , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom
| | - Yuval Elani
- Department of Chemistry , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom.,Institute of Chemical Biology , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom.,fabriCELL, Molecular Sciences Research Hub , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom
| | - Tatiana Trantidou
- Department of Chemistry , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom
| | - Oscar Ces
- Department of Chemistry , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom.,Institute of Chemical Biology , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom.,fabriCELL, Molecular Sciences Research Hub , Imperial College London , Wood Lane , London , W12 0BZ , United Kingdom
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6
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Okuno D, Hirano M, Yokota H, Onishi Y, Ichinose J, Ide T. A Simple Method for Ion Channel Recordings Using Fine Gold Electrode. ANAL SCI 2018; 32:1353-1357. [PMID: 27941267 DOI: 10.2116/analsci.32.1353] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The artificial bilayer single-channel recording technique is commonly used to observe detailed pharmacological properties of various ion channel proteins. It permits easy control of the solution and membrane lipid composition, and is also compatible with pharmacological screening devices. However, its use is limited due to low measurement efficiency. Here, we develop a novel artificial bilayer single-channel recording technique in which bilayers are made and channels are reconstituted into the membranes by contacting a gold electrode to the lipid-solution interface. Using this technique, we measured the single-channel currents of two channel-forming peptides, gramicidin and alamethicin, and a channel-forming protein, α-hemolysin. This technique requires only one action, allowing the technique to potentially be combined with high-throughput screening devices.
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Affiliation(s)
- Daichi Okuno
- Laboratory for Cell Dynamics Observation, Quantitative Biology Center, Riken
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7
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Booth MJ, Restrepo Schild V, Downs FG, Bayley H. Functional aqueous droplet networks. MOLECULAR BIOSYSTEMS 2018; 13:1658-1691. [PMID: 28766622 DOI: 10.1039/c7mb00192d] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Droplet interface bilayers (DIBs), comprising individual lipid bilayers between pairs of aqueous droplets in an oil, are proving to be a useful tool for studying membrane proteins. Recently, attention has turned to the elaboration of networks of aqueous droplets, connected through functionalized interface bilayers, with collective properties unachievable in droplet pairs. Small 2D collections of droplets have been formed into soft biodevices, which can act as electronic components, light-sensors and batteries. A substantial breakthrough has been the development of a droplet printer, which can create patterned 3D droplet networks of hundreds to thousands of connected droplets. The 3D networks can change shape, or carry electrical signals through defined pathways, or express proteins in response to patterned illumination. We envisage using functional 3D droplet networks as autonomous synthetic tissues or coupling them with cells to repair or enhance the properties of living tissues.
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Affiliation(s)
- Michael J Booth
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
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8
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Okuno D, Hirano M, Yokota H, Ichinose J, Kira T, Hijiya T, Uozumi C, Yamakami M, Ide T. A gold nano-electrode for single ion channel recordings. NANOSCALE 2018; 10:4036-4040. [PMID: 29431813 DOI: 10.1039/c7nr08098k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The artificial bilayer single channel recording technique is commonly used to observe the detailed physiological properties of various ion channel proteins. It permits easy control of the solution and membrane lipid composition, and is also compatible with pharmacological screening devices. However, its use is limited due to low measurement efficiency. Here, we developed a novel artificial bilayer single channel recording technique in which solubilized ion channel proteins immobilized on a gold nano-electrode are directly incorporated into a lipid bilayer at the same time as the bilayer is formed at the tip of it on coming in contact with an aqueous-oil interface. Using this technique, we measured the single channel currents of several types of channels including KcsA, MthK, hBK and P2X4. This technique requires only one action to simultaneously form the bilayers and reconstitute the channels into the membranes. This simplicity greatly increases the measurement efficiency and allows the technique to potentially be combined with high-throughput screening devices.
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Affiliation(s)
- Daichi Okuno
- Laboratory for Cell Dynamics Observation, Quantitative Biology Center, Riken, 6-2-3 Furue-dai Suita, Osaka 565-0874, Japan
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9
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Schmidt J. Membrane platforms for biological nanopore sensing and sequencing. Curr Opin Biotechnol 2016; 39:17-27. [PMID: 26773300 DOI: 10.1016/j.copbio.2015.12.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/18/2015] [Accepted: 12/18/2015] [Indexed: 12/12/2022]
Abstract
In the past two decades, biological nanopores have been developed and explored for use in sensing applications as a result of their exquisite sensitivity and easily engineered, reproducible, and economically manufactured structures. Nanopore sensing has been shown to differentiate between highly similar analytes, measure polymer size, detect the presence of specific genes, and rapidly sequence nucleic acids translocating through the pore. Devices featuring protein nanopores have been limited in part by the membrane support containing the nanopore, the shortcomings of which have been addressed in recent work developing new materials, approaches, and apparatus resulting in membrane platforms featuring automatability and increased robustness, lifetime, and measurement throughput.
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Affiliation(s)
- Jacob Schmidt
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA 90095, USA.
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10
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Vijayvergiya V, Acharya S, Poulos J, Schmidt J. Single channel and ensemble hERG conductance measured in droplet bilayers. Biomed Microdevices 2015; 17:12. [PMID: 25653065 DOI: 10.1007/s10544-014-9919-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The human ether-a-go-go related gene (hERG) encodes the potassium channel Kv11.1, which plays a key role in the cardiac action potential and has been implicated in cardiac disorders as well as a number of off-target pharmaceutical interactions. The electrophysiology of this channel has been predominantly studied using patch clamp, but lipid bilayers have the potential to offer some advantages, including apparatus simplicity, ease of use, and the ability to control the membrane and solution compositions. We made membrane preparations from hERG-expressing cells and measured them using droplet bilayers, allowing measurement of channel ensemble currents and 13.5 pS single channel currents. These currents were ion selective and were blockable by E-4031 and dofetilide in a dose-dependent manner, allowing determination of IC50 values of 17 nM and 9.65 μM for E-4031 and dofetilide, respectively. We also observed time- and voltage- dependent currents following step changes in applied potential that were similar to previously reported patch clamp measurements.
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Affiliation(s)
- Viksita Vijayvergiya
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
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11
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Hirano-Iwata A, Ishinari Y, Yamamoto H, Niwano M. Micro- and Nano-Technologies for Lipid Bilayer-Based Ion-Channel Functional Assays. Chem Asian J 2015; 10:1266-74. [DOI: 10.1002/asia.201403391] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Ayumi Hirano-Iwata
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Yutaka Ishinari
- CREST (Japan) Science and Technology Agency (JST); 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
| | - Hideaki Yamamoto
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Frontier Research Institute for Interdisciplinary Sciences; Tohoku University; 6-3 Aoba Aramaki, Aoba-ku Sendai 980-8578 Japan
| | - Michio Niwano
- Graduate School of Biomedical Engineering; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
- Laboratory for Nanoelectronics and Spintronics; Research Institute of Electrical Communication; Tohoku University; 6-6 Aoba Aramaki, Aoba-ku Sendai 980-8579 Japan
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12
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Wang Y, Montana V, Grubišić V, Stout RF, Parpura V, Gu LQ. Nanopore sensing of botulinum toxin type B by discriminating an enzymatically cleaved Peptide from a synaptic protein synaptobrevin 2 derivative. ACS APPLIED MATERIALS & INTERFACES 2015; 7:184-92. [PMID: 25511125 PMCID: PMC4296922 DOI: 10.1021/am5056596] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Botulinum neurotoxins (BoNTs) are the most lethal toxin known to human. Biodefense requires early and rapid detection of BoNTs. Traditionally, BoNTs can be detected by looking for signs of botulism in mice that receive an injection of human material, serum or stool. While the living animal assay remains the most sensitive approach, it is costly, slow and associated with legal and ethical constrains. Various biochemical, optical and mechanical methods have been developed for BoNTs detection with improved speed, but with lesser sensitivity. Here, we report a novel nanopore-based BoNT type B (BoNT-B) sensor that monitors the toxin's enzymatic activity on its substrate, a recombinant synaptic protein synaptobrevin 2 derivative. By analyzing the modulation of the pore current caused by the specific BoNT-B-digested peptide as a marker, the presence of BoNT-B at a subnanomolar concentration was identified within minutes. The nanopore detector would fill the niche for a much needed rapid and highly sensitive detection of neurotoxins, and provide an excellent system to explore biophysical mechanisms for biopolymer transportation.
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Affiliation(s)
- Yong Wang
- Department
of Bioengineering and Dalton Cardiovascular Research
Center, University of Missouri, Columbia, Missouri 65211, United States
- Dr. Yong Wang. E-mail:
| | - Vedrana Montana
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
| | - Vladimir Grubišić
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Randy F. Stout
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
- Department of Neuroscience, Albert Einstein
College of Medicine, Bronx, New
York, New York 10461, United States
| | - Vladimir Parpura
- Department
of Neurobiology, Center for Glial Biology in Medicine,
Atomic Force Microscopy & Nanotechnology Laboratories, Civitan
International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
- Dr. Vladimir Parpura.
E-mail:
| | - Li-Qun Gu
- Department
of Bioengineering and Dalton Cardiovascular Research
Center, University of Missouri, Columbia, Missouri 65211, United States
- Dr. Li-Qun Gu. E-mail:
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13
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Saha SC, Powl AM, Wallace BA, de Planque MRR, Morgan H. Screening ion-channel ligand interactions with passive pumping in a microfluidic bilayer lipid membrane chip. BIOMICROFLUIDICS 2015; 9:014103. [PMID: 25610515 PMCID: PMC4288537 DOI: 10.1063/1.4905313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 12/19/2014] [Indexed: 05/16/2023]
Abstract
We describe a scalable artificial bilayer lipid membrane platform for rapid electrophysiological screening of ion channels and transporters. A passive pumping method is used to flow microliter volumes of ligand solution across a suspended bilayer within a microfluidic chip. Bilayers are stable at flow rates up to ∼0.5 μl/min. Phospholipid bilayers are formed across a photolithographically defined aperture made in a dry film resist within the microfluidic chip. Bilayers are stable for many days and the low shunt capacitance of the thin film support gives low-noise high-quality single ion channel recording. Dose-dependent transient blocking of α-hemolysin with β-cyclodextrin (β-CD) and polyethylene glycol is demonstrated and dose-dependent blocking studies of the KcsA potassium channel with tetraethylammonium show the potential for determining IC50 values. The assays are fast (30 min for a complete IC50 curve) and simple and require very small amounts of compounds (100 μg in 15 μl). The technology can be scaled so that multiple bilayers can be addressed, providing a screening platform for ion channels, transporters, and nanopores.
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Affiliation(s)
- Shimul C Saha
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Andrew M Powl
- Institute of Structural and Molecular Biology, Birkbeck College, University of London , London WC1E 7HX, United Kingdom
| | - B A Wallace
- Institute of Structural and Molecular Biology, Birkbeck College, University of London , London WC1E 7HX, United Kingdom
| | - Maurits R R de Planque
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Hywel Morgan
- Electronics and Computer Science and Institute for Life Sciences, University of Southampton , Southampton SO17 1BJ, United Kingdom
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14
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Abstract
Artificial lipid bilayers have many uses. They are well established for scientific studies of reconstituted ion channels, used to host engineered pore proteins for sensing, and can potentially be applied in DNA sequencing. Droplet bilayers have significant technological potential for enabling many of these applications due to their compatibility with automation and array platforms. To further develop this potential, we have simplified the formation and electrical measurement of droplet bilayers using an apparatus that only requires fluid dispensation. We achieved simultaneous bilayer formation and measurement over a 32-element array with ~80% yield and no operator input following fluid addition. Cycling these arrays resulted in the formation and measurement of 96 out of 120 possible bilayers in 80 minutes, a sustainable rate that could significantly increase with automation and greater parallelization. This turn-key, high-yield approach to making artificial lipid bilayers requires no training, making the capability of creating and measuring lipid bilayers and ion channels accessible to a much wider audience. In addition, this approach is low-cost, parallelizable, and automatable, allowing high-throughput studies of ion channels and pore proteins in lipid bilayers for sensing or screening applications.
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15
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Hydrogel-stabilized droplet bilayers for high speed solution exchange. Sci Rep 2013; 3:3139. [PMID: 24190577 PMCID: PMC3817439 DOI: 10.1038/srep03139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 10/18/2013] [Indexed: 11/18/2022] Open
Abstract
Many applications utilizing artificial lipid bilayers require the ability to exchange the bilayer's solution environment. However, because of the instability of the bilayer, the rate of solution exchange is limited, which significantly hinders the measurement rate and throughput. We have developed an artificial bilayer system that can withstand high flow speeds, up to 2.1 m/s, by supporting the bilayer with a hydrogel. We demonstrated the ability to measure during flow by measuring the conductance of gramicidin-A channels while switching between solutions of two different compositions, recording a time to measure 90% change in current of approximately 2.7 seconds at a flow rate of 0.1 m/s. We also demonstrated a potential application of this system by measuring the conductance modulation of the rat TRPM8 ion channel by an agonist and antagonist at varying concentrations, obtaining 7-point IC50 and EC50 values in approximately 7 minutes and 4-point values within 4 minutes.
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16
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Portonovo SA, Salazar CS, Schmidt JJ. hERG drug response measured in droplet bilayers. Biomed Microdevices 2013; 15:255-9. [PMID: 23160842 DOI: 10.1007/s10544-012-9725-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We show measurements of the human cardiac potassium ion channel Kv11.1 (hERG) in droplet bilayers incorporated directly from commercial membrane preparations of HEK293 cells. Although we do not obtain ensemble conductance kinetics and rectification observed in patch clamp measurements of hERG, ensemble currents measured in our system showed inhibition dependent on astemizole and E-4031 concentration, with IC50 values similar to those found with patch clamp. The availability of engineered HEK cells expressing a variety of ion channels, combined with the simplicity of the inhibition measurement, suggest that droplet bilayers may have considerable technological potential for determination of ion channel drug potency.
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Affiliation(s)
- Shiva A Portonovo
- Department of Bioengineering, University of California, Los Angeles, 5121 Engineering V, 420 Westwood Plaza, Los Angeles, CA 90095, USA
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17
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Lein M, Huang J, Holden MA. Robust reagent addition and perfusion strategies for droplet-interface bilayers. LAB ON A CHIP 2013; 13:2749-53. [PMID: 23685850 DOI: 10.1039/c3lc41323c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We have designed two novel devices which extend the applications for the droplet-interface bilayer (DIB) as a model membrane system. The add-chip allows successive reagent additions to one side of the lipid bilayer during an experiment while maintaining a simple setup with much lower volumes than in planar bilayer systems. The flow-chip is capable of multiple complete solution perfusions concurrently with electrophysiology measurements. Both devices preserve all of the key advantages that DIBs have relative to planar membranes, including low volume, leaflet asymmetry and the ability to separate the monolayers prior to further analysis of a droplet's contents. As a demonstration, we use these devices to monitor and quantitate molecular transport across DIBs.
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Affiliation(s)
- Max Lein
- Department of Chemistry, University of Massachusetts, 710 North Pleasant St, Amherst, MA 01003, USA
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18
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Leptihn S, Castell OK, Cronin B, Lee EH, Gross LCM, Marshall DP, Thompson JR, Holden M, Wallace MI. Constructing droplet interface bilayers from the contact of aqueous droplets in oil. Nat Protoc 2013; 8:1048-57. [DOI: 10.1038/nprot.2013.061] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Oshima A, Hirano-Iwata A, Mozumi H, Ishinari Y, Kimura Y, Niwano M. Reconstitution of Human Ether-a-go-go-Related Gene Channels in Microfabricated Silicon Chips. Anal Chem 2013; 85:4363-9. [DOI: 10.1021/ac303484k] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Azusa Oshima
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Ayumi Hirano-Iwata
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
- PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho Kawaguchi,
Saitama 332-0012, Japan
| | - Hideki Mozumi
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Yutaka Ishinari
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
| | - Yasuo Kimura
- Laboratory
for Nanoelectronics
and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai,
Miyagi 980-8577, Japan
| | - Michio Niwano
- Graduate School of Biomedical
Engineering, Tohoku University, 6-6 Aoba,
Aramaki, Aoba-ku, Sendai 980-8579, Japan
- Laboratory
for Nanoelectronics
and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai,
Miyagi 980-8577, Japan
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20
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El-Arabi AM, Salazar CS, Schmidt JJ. Ion channel drug potency assay with an artificial bilayer chip. LAB ON A CHIP 2012; 12:2409-2413. [PMID: 22549308 DOI: 10.1039/c2lc40087a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The potency of pharmaceutical compounds acting on ion channels can be determined through measurements of ion channel conductance as a function of compound concentration. We have developed an artificial lipid bilayer chip for simple, fast, and high-yield measurement of ion channel conductance with simultaneous solution perfusion. Here we show the application of this chip to the measurement of the mammalian cold and menthol receptor TRPM8. Ensemble measurements of TRPM8 as a function of concentration of menthol and 2-aminoethoxydiphenyl borate (2-APB) enabled efficient determination of menthol's EC(50) (111.8 μM ± 2.4 μM) and 2-APB's IC(50) (4.9 μM ± 0.2 μM) in agreement with published values. This validation, coupled with the compatibility of this platform with automation and parallelization, indicates significant potential for large-scale pharmaceutical ion channel screening.
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Affiliation(s)
- Ahmad M El-Arabi
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
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