1
|
Ogishi K, Osaki T, Mimura H, Hashimoto I, Morimoto Y, Miki N, Takeuchi S. Real-time quantitative characterization of ion channel activities for automated control of a lipid bilayer system. Biosens Bioelectron 2023; 237:115490. [PMID: 37393766 DOI: 10.1016/j.bios.2023.115490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/16/2023] [Accepted: 06/19/2023] [Indexed: 07/04/2023]
Abstract
This paper describes a novel signal processing method to characterize the activity of ion channels on a lipid bilayer system in a real-time and quantitative manner. Lipid bilayer systems, which enable single-channel level recordings of ion channel activities against physiological stimuli in vitro, are gaining attention in various research fields. However, the characterization of ion channel activities has heavily relied on time-consuming analyses after recording, and the inability to return the quantitative results in real time has long been a bottleneck to incorporating the system into practical products. Herein, we report a lipid bilayer system that integrates real-time characterization of ion channel activities and real-time response based on the characterization result. Unlike conventional batch processing, an ion channel signal is divided into short segments and processed during the recording. After optimizing the system to maintain the same characterization accuracy as conventional operation, we demonstrated the usability of the system with two applications. One is quantitative control of a robot based on ion channel signals. The velocity of the robot was controlled every second, which was around tens of times faster than the conventional operation, in proportion to the stimulus intensity estimated from changes in ion channel activities. The other is the automation of data collection and characterization of ion channels. By constantly monitoring and maintaining the functionality of a lipid bilayer, our system enabled continuous recording of ion channels over 2 h without human intervention, and the time of manual labor has been reduced from conventional 3 h to 1 min at a minimum. We believe the accelerated characterization and response in the lipid bilayer systems presented in this work will facilitate the transformation of lipid bilayer technology toward a practical level, finally leading to its industrialization.
Collapse
Affiliation(s)
- Kazuto Ogishi
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Toshihisa Osaki
- Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan
| | - Hisatoshi Mimura
- Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan
| | - Izumi Hashimoto
- Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan; Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa, 223-8522, Japan
| | - Yuya Morimoto
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Norihisa Miki
- Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan; Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa, 223-8522, Japan
| | - Shoji Takeuchi
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan; Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa, 213-0012, Japan; Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
| |
Collapse
|
2
|
Baxani DK, Jamieson WD, Barrow DA, Castell OK. Encapsulated droplet interface bilayers as a platform for high-throughput membrane studies. SOFT MATTER 2022; 18:5089-5096. [PMID: 35766018 PMCID: PMC9277618 DOI: 10.1039/d1sm01111a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Whilst it is highly desirable to produce artificial lipid bilayer arrays allowing for systematic high-content screening of membrane conditions, it remains a challenge due to the combined requirements of scaled membrane production, simple measurement access, and independent control over individual bilayer experimental conditions. Here, droplet bilayers encapsulated within a hydrogel shell are output individually into multi-well plates for simple, arrayed quantitative measurements. The afforded experimental throughput is used to conduct a 2D concentration screen characterising the synergistic pore-forming peptides Magainin2 and PGLa. Maximal enhanced activity is revealed at equimolar peptide concentrations via a membrane dye leakage assay, a finding consistent with models proposed from NMR data. The versatility of the platform is demonstrated by performing in situ electrophysiology, revealing low conductance pore activity (∼15 to 20 pA with 4.5 pA sub-states). In conclusion, this array platform addresses the aforementioned challenges and provides new and flexible opportunities for high-throughput membrane studies. Furthermore, the ability to engineer droplet networks within each construct paves the way for "lab-in-a-capsule" approaches accommodating multiple assays per construct and allowing for communicative reaction pathways.
Collapse
Affiliation(s)
- D K Baxani
- College of Biomedical and Life Sciences, School of Pharmacy and Pharmaceutical Sciences, Cardiff University Redwood Building, King Edward VII Avenue, CF10 3NB Cardiff, UK.
| | - W D Jamieson
- College of Biomedical and Life Sciences, School of Pharmacy and Pharmaceutical Sciences, Cardiff University Redwood Building, King Edward VII Avenue, CF10 3NB Cardiff, UK.
| | - D A Barrow
- School of Engineering, Cardiff University, 14-17 The Parade, CF4 3AA Cardiff, UK
| | - O K Castell
- College of Biomedical and Life Sciences, School of Pharmacy and Pharmaceutical Sciences, Cardiff University Redwood Building, King Edward VII Avenue, CF10 3NB Cardiff, UK.
| |
Collapse
|
3
|
Han WB, Kang DH, Kim TS. 3D Artificial Cell Membranes as Versatile Platforms for Biological Applications. BIOCHIP JOURNAL 2022. [DOI: 10.1007/s13206-022-00066-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
4
|
Du X, Wang Y, Zhang S, Fan P, Yan S, Zhang P, Chen HY, Huang S. Microscopic Screening of Cyclodextrin Channel Blockers by DiffusiOptoPhysiology. Anal Chem 2021; 93:14161-14168. [PMID: 34641671 DOI: 10.1021/acs.analchem.1c02775] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Blockers of pore-forming toxins (PFTs) limit bacterial virulence by blocking relevant channel proteins. However, screening of desired blockers from a large pool of candidate molecules is not a trivial task. Acknowledging its advantages of low cost, high throughput, and multiplicity, DiffusiOptoPhysiology (DOP), an emerging nanopore technique that visually monitors the states of individual channel proteins without using any electrodes, has shown its potential use in the screening of channel blockers. By taking different α-hemolysin (α-HL) mutants as model PFTs and different cyclodextrins as model blockers, we report direct screening of pore blockers solely by using fluorescence microscopy. Different combinations of pores and blockers were simultaneously evaluated on the same DOP chip and a single-molecule resolution is directly achieved. The entire chip is composed of low-cost and biocompatible materials, which is fully disposable after each use. Though only demonstrated with cyclodextrin derivatives and α-HL mutants, this proof of concept has also suggested its generality to investigate other pore-forming proteins.
Collapse
Affiliation(s)
- Xiaoyu Du
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Yuqin Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Shanyu Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Pingping Fan
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Shuanghong Yan
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing 210023, China
| |
Collapse
|
5
|
Novikova OD, Naberezhnykh GA, Sergeev AA. Nanostructured Biosensors Based on Components of Bacterial Membranes. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921040187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
|
6
|
Misawa N, Osaki T, Takeuchi S. Membrane protein-based biosensors. J R Soc Interface 2019; 15:rsif.2017.0952. [PMID: 29669891 DOI: 10.1098/rsif.2017.0952] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/19/2018] [Indexed: 01/09/2023] Open
Abstract
This review highlights recent development of biosensors that use the functions of membrane proteins. Membrane proteins are essential components of biological membranes and have a central role in detection of various environmental stimuli such as olfaction and gustation. A number of studies have attempted for development of biosensors using the sensing property of these membrane proteins. Their specificity to target molecules is particularly attractive as it is significantly superior to that of traditional human-made sensors. In this review, we classified the membrane protein-based biosensors into two platforms: the lipid bilayer-based platform and the cell-based platform. On lipid bilayer platforms, the membrane proteins are embedded in a lipid bilayer that bridges between the protein and a sensor device. On cell-based platforms, the membrane proteins are expressed in a cultured cell, which is then integrated in a sensor device. For both platforms we introduce the fundamental information and the recent progress in the development of the biosensors, and remark on the outlook for practical biosensing applications.
Collapse
Affiliation(s)
- Nobuo Misawa
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu, Kawasaki 213-0012, Japan
| | - Toshihisa Osaki
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu, Kawasaki 213-0012, Japan.,Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan
| | - Shoji Takeuchi
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu, Kawasaki 213-0012, Japan .,Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505, Japan
| |
Collapse
|
7
|
Mei J, Fu Y, Zhao J. Analysis and prediction of ion channel inhibitors by using feature selection and Chou's general pseudo amino acid composition. J Theor Biol 2018; 456:41-48. [DOI: 10.1016/j.jtbi.2018.07.040] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 07/20/2018] [Accepted: 07/29/2018] [Indexed: 12/23/2022]
|
8
|
Guiselin B, Law JO, Chakrabarti B, Kusumaatmaja H. Dynamic Morphologies and Stability of Droplet Interface Bilayers. PHYSICAL REVIEW LETTERS 2018; 120:238001. [PMID: 29932701 DOI: 10.1103/physrevlett.120.238001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 01/24/2018] [Indexed: 06/08/2023]
Abstract
We develop a theoretical framework for understanding dynamic morphologies and stability of droplet interface bilayers (DIBs), accounting for lipid kinetics in the monolayers and bilayer, and droplet evaporation due to imbalance between osmotic and Laplace pressures. Our theory quantitatively describes distinct pathways observed in experiments when DIBs become unstable. We find that when the timescale for lipid desorption is slow compared to droplet evaporation, the lipid bilayer will grow and the droplets approach a hemispherical shape. In contrast, when lipid desorption is fast, the bilayer area will shrink and the droplets eventually detach. Our model also suggests there is a critical size below which DIBs can become unstable, which may explain experimental difficulties in miniaturizing the DIB platform.
Collapse
Affiliation(s)
- Benjamin Guiselin
- Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - Jack O Law
- Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| | - Buddhapriya Chakrabarti
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom
| | - Halim Kusumaatmaja
- Department of Physics, Durham University, Durham DH1 3LE, United Kingdom
| |
Collapse
|
9
|
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.
Collapse
Affiliation(s)
- Michael J Booth
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | | | | | | |
Collapse
|
10
|
Mazur F, Bally M, Städler B, Chandrawati R. Liposomes and lipid bilayers in biosensors. Adv Colloid Interface Sci 2017; 249:88-99. [PMID: 28602208 DOI: 10.1016/j.cis.2017.05.020] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/30/2017] [Indexed: 10/19/2022]
Abstract
Biosensors for the rapid, specific, and sensitive detection of analytes play a vital role in healthcare, drug discovery, food safety, and environmental monitoring. Although a number of sensing concepts and devices have been developed, many longstanding challenges to obtain inexpensive, easy-to-use, and reliable sensor platforms remain largely unmet. Nanomaterials offer exciting possibilities for enhancing the assay sensitivity and for lowering the detection limits down to single-molecule resolution. In this review, we present an overview of liposomes and lipid bilayers in biosensing applications. Lipid assemblies in the form of spherical liposomes or two-dimensional planar membranes have been widely used in the design of biosensing assays; in particular, we highlight a number of recent promising developments of biosensors based on liposomes in suspension, liposome arrays, and lipid bilayers arrays. Assay sensitivity and specificity are discussed, advantages and drawbacks are reviewed, and possible further developments are outlined.
Collapse
|
11
|
Agasid MT, Comi TJ, Saavedra SS, Aspinwall CA. Enhanced Temporal Resolution with Ion Channel-Functionalized Sensors Using a Conductance-Based Measurement Protocol. Anal Chem 2017; 89:1315-1322. [PMID: 27981836 PMCID: PMC5862562 DOI: 10.1021/acs.analchem.6b04226] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The binding of a target analyte to an ion channel (IC), which is readily detected electrochemically in a label-free manner with single-molecule selectivity and specificity, has generated widespread interest in using natural and engineered ICs as transducers in biosensing platforms. To date, the majority of developments in IC-functionalized sensing have focused on IC selectivity or sensitivity or development of suitable membrane environments and aperture geometries. Comparatively little work has addressed analytical performance criteria, particularly criteria required for temporal measurements of dynamic processes. We report a measurement protocol suitable for rapid, time-resolved monitoring (≤30 ms) of IC-modulated membrane conductance. Key features of this protocol include the reduction of membrane area and the use of small voltage steps (10 mV) and short duration voltage pulses (10 ms), which have the net effect of reducing the capacitive charging and decreasing the time required to achieve steady state currents. Application of a conductance protocol employing three sequential, 10 ms voltage steps (-10 mV, -20 mV, -30 mV) in an alternating, pyramid-like arrangement enabled sampling of membrane conductance every 30 ms. Using this protocol, dynamic IC measurements on black lipid membranes (BLMs) functionalized with gramicidin A were conducted using a fast perfusion system. BLM conductance decreased by 76 ± 7.5% within 30 ms of switching from solutions containing 0 to 1 M Ca2+, which demonstrates the feasibility of using this approach to monitor rapid, dynamic chemical processes. Rapid conductance measurements will be broadly applicable to IC-based sensors that undergo analyte-specific gating.
Collapse
Affiliation(s)
- Mark T. Agasid
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - Troy J. Comi
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - S. Scott Saavedra
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
- BIO5 Institute, University of Arizona, Tucson, AZ 85721
| | - Craig A. Aspinwall
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
- BIO5 Institute, University of Arizona, Tucson, AZ 85721
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ 85721
| |
Collapse
|
12
|
Affiliation(s)
- Toshihisa Osaki
- Artificial Cell
Membrane
Systems Group, Kanagawa Academy of Science and Technology, 3-2-1
Sakado, Takatsu, 213-0012 Kawasaki, Japan
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, 153-8505 Tokyo, Japan
| | - Shoji Takeuchi
- Artificial Cell
Membrane
Systems Group, Kanagawa Academy of Science and Technology, 3-2-1
Sakado, Takatsu, 213-0012 Kawasaki, Japan
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, 153-8505 Tokyo, Japan
| |
Collapse
|
13
|
Walsh E, Feuerborn A, Cook PR. Formation of droplet interface bilayers in a Teflon tube. Sci Rep 2016; 6:34355. [PMID: 27681313 PMCID: PMC5041184 DOI: 10.1038/srep34355] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/09/2016] [Indexed: 02/08/2023] Open
Abstract
Droplet-interface bilayers (DIBs) have applications in disciplines ranging from biology to computing. We present a method for forming them manually using a Teflon tube attached to a syringe pump; this method is simple enough it should be accessible to those without expertise in microfluidics. It exploits the properties of interfaces between three immiscible liquids, and uses fluid flow through the tube to pack together drops coated with lipid monolayers to create bilayers at points of contact. It is used to create functional nanopores in DIBs composed of phosphocholine using the protein α-hemolysin (αHL), to demonstrate osmotically-driven mass transfer of fluid across surfactant-based DIBs, and to create arrays of DIBs. The approach is scalable, and thousands of DIBs can be prepared using a robot in one hour; therefore, it is feasible to use it for high throughput applications.
Collapse
Affiliation(s)
- Edmond Walsh
- Osney Thermo-Fluids Laboratory, Department of Engineering Science, University of Oxford, Southwell Building, Osney Mead, Oxford OX2 0ES, UK
| | - Alexander Feuerborn
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Peter R Cook
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| |
Collapse
|
14
|
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.
Collapse
Affiliation(s)
- Jacob Schmidt
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
15
|
|
16
|
Vijayvergiya V, Acharya S, Wilson SP, Schmidt JJ. Measurement of Ensemble TRPV1 Ion Channel Currents Using Droplet Bilayers. PLoS One 2015; 10:e0141366. [PMID: 26513481 PMCID: PMC4626236 DOI: 10.1371/journal.pone.0141366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 10/06/2015] [Indexed: 11/18/2022] Open
Abstract
Electrophysiological characterization of ion channels is useful for elucidation of channel function as well as quantitative assessment of pharmaceutical effects on ion channel conductance. We used droplet bilayers to measure ensemble ion channel currents from membrane preparations made from TRPV1-expressing HEK cells. Conductance measurements showed rectification, activation by acid and capsaicin, and inhibition by capsazepine, SB 452533, and JNJ 17293212. We also quantitatively measured concentration-dependent inhibition of channel conductance through determination of capsazepine IC50 in agreement with previously published studies using patch clamp. These results, combined with the reduced apparatus and material requirements of droplet bilayers, indicate that this platform could be used for study of other physiologically relevant ion channels.
Collapse
Affiliation(s)
- Viksita Vijayvergiya
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Shiv Acharya
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sidney P. Wilson
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jacob J. Schmidt
- Department of Bioengineering, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
| |
Collapse
|
17
|
Taylor GJ, Venkatesan GA, Collier CP, Sarles SA. Direct in situ measurement of specific capacitance, monolayer tension, and bilayer tension in a droplet interface bilayer. SOFT MATTER 2015; 11:7592-605. [PMID: 26289743 DOI: 10.1039/c5sm01005e] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Thickness and tension are important physical parameters of model cell membranes. However, traditional methods to measure these quantities require multiple experiments using separate equipment. This work introduces a new multi-step procedure for directly accessing in situ multiple physical properties of droplet interface bilayers (DIB), including specific capacitance (related to thickness), lipid monolayer tension in the Plateau-Gibbs border, and bilayer tension. The procedure employs a combination of mechanical manipulation of bilayer area followed by electrowetting of the capacitive interface to examine the sensitivities of bilayer capacitance to area and contact angle to voltage, respectively. These data allow for determining the specific capacitance of the membrane and surface tension of the lipid monolayer, which are then used to compute bilayer thickness and tension, respectively. The use of DIBs affords accurate optical imaging of the connected droplets in addition to electrical measurements of bilayer capacitance, and it allows for reversibly varying bilayer area. After validating the accuracy of the technique with diphytanoyl phosphatidylcholine (DPhPC) DIBs in hexadecane, the method is applied herein to quantify separately the effects on membrane thickness and tension caused by varying the solvent in which the DIB is formed and introducing cholesterol into the bilayer. Because the technique relies only on capacitance measurements and optical images to determine both thickness and tension, this approach is specifically well-suited for studying the effects of peptides, biomolecules, natural and synthetic nanoparticles, and other species that accumulate within membranes without altering bilayer conductance.
Collapse
Affiliation(s)
- Graham J Taylor
- Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, 1512 Middle Drive, 414 Dougherty Engineering Building, Knoxville, TN 37996, USA.
| | | | | | | |
Collapse
|
18
|
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
| |
Collapse
|
19
|
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.
Collapse
|
20
|
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]
|
21
|
Boreyko JB, Polizos G, Datskos PG, Sarles SA, Collier CP. Air-stable droplet interface bilayers on oil-infused surfaces. Proc Natl Acad Sci U S A 2014; 111:7588-93. [PMID: 24821774 PMCID: PMC4040577 DOI: 10.1073/pnas.1400381111] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Droplet interface bilayers are versatile model membranes useful for synthetic biology and biosensing; however, to date they have always been confined to fluid reservoirs. Here, we demonstrate that when two or more water droplets collide on an oil-infused substrate, they exhibit noncoalescence due to the formation of a thin oil film that gets squeezed between the droplets from the bottom up. We show that when phospholipids are included in the water droplets, a stable droplet interface bilayer forms between the noncoalescing water droplets. As with traditional oil-submerged droplet interface bilayers, we were able to characterize ion channel transport by incorporating peptides into each droplet. Our findings reveal that droplet interface bilayers can function in ambient environments, which could potentially enable biosensing of airborne matter.
Collapse
Affiliation(s)
| | - Georgios Polizos
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831; and
| | - Panos G Datskos
- Energy and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831; and
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996
| | | |
Collapse
|
22
|
Kredics L, Szekeres A, Czifra D, Vágvölgyi C, Leitgeb B. Recent results in alamethicin research. Chem Biodivers 2013; 10:744-71. [PMID: 23681724 DOI: 10.1002/cbdv.201200390] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Indexed: 12/20/2022]
Affiliation(s)
- László Kredics
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, H-6726 Szeged.
| | | | | | | | | |
Collapse
|
23
|
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.
Collapse
|
24
|
Baker CA, Bright LK, Aspinwall CA. Photolithographic fabrication of microapertures with well-defined, three-dimensional geometries for suspended lipid membrane studies. Anal Chem 2013; 85:9078-86. [PMID: 23987300 DOI: 10.1021/ac401639n] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Robust and high-density biosensors incorporating suspended lipid membranes require microfabricated apertures that can be readily integrated into complex analysis systems. Apertures with well-defined, three-dimensional geometries enable the formation of suspended lipid membranes and facilitate reduced aperture size compared to vertical-walled apertures. Unfortunately, existing methods of producing apertures with well-defined, three-dimensional geometries are based on complex and expensive fabrication procedures, some of which yield apertures in excessively fragile thin-film materials. Here, we describe a microfabrication method utilizing incline and rotate lithography that achieves sloped-wall microapertures in SU-8 polymer substrates with precision control of the aperture diameter, substrate thickness, and wall angle. This approach is simple, is of low cost, and is readily scaled up to allow highly reproducible parallel fabrication. The effect of the incident angle of UV exposure and the size of photomask features on the aperture geometry were investigated, yielding aperture diameters as small as 7 μm and aperture wall angles ranging from 8° to 36° measured from the normal axis. Black lipid membranes were suspended across the apertures and showed normalized conductance values of 0.02-0.05 pS μm(-2) and breakdown voltages of 400-600 mV. The functionality of the resulting sloped-wall microapertures was validated via measurement of reconstituted α-hemolysin activity and the voltage-gated channel activity of alamethicin.
Collapse
Affiliation(s)
- Christopher A Baker
- Department of Chemistry and Biochemistry, University of Arizona , 1306 East University Boulevard, Tucson, Arizona 85721, United States
| | | | | |
Collapse
|
25
|
Costa JA, Nguyen DA, Leal-Pinto E, Gordon RE, Hanss B. Wicking: a rapid method for manually inserting ion channels into planar lipid bilayers. PLoS One 2013; 8:e60836. [PMID: 23717384 PMCID: PMC3662662 DOI: 10.1371/journal.pone.0060836] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 03/03/2013] [Indexed: 11/18/2022] Open
Abstract
The planar lipid bilayer technique has a distinguished history in electrophysiology but is arguably the most technically difficult and time-consuming method in the field. Behind this is a lack of experimental consistency between laboratories, the challenges associated with painting unilamellar bilayers, and the reconstitution of ion channels into them. While there has be a trend towards automation of this technique, there remain many instances where manual bilayer formation and subsequent membrane protein insertion is both required and advantageous. We have developed a comprehensive method, which we have termed “wicking”, that greatly simplifies many experimental aspects of the lipid bilayer system. Wicking allows one to manually insert ion channels into planar lipid bilayers in a matter of seconds, without the use of a magnetic stir bar or the addition of other chemicals to monitor or promote the fusion of proteoliposomes. We used the wicking method in conjunction with a standard membrane capacitance test and a simple method of proteoliposome preparation that generates a heterogeneous mixture of vesicle sizes. To determine the robustness of this technique, we selected two ion channels that have been well characterized in the literature: CLIC1 and α-hemolysin. When reconstituted using the wicking technique, CLIC1 showed biophysical characteristics congruent with published reports from other groups; and α-hemolysin demonstrated Type A and B events when threading single stranded DNA through the pore. We conclude that the wicking method gives the investigator a high degree of control over many aspects of the lipid bilayer system, while greatly reducing the time required for channel reconstitution.
Collapse
Affiliation(s)
- Justin A. Costa
- Division of Nephrology, Department of Medicine and Graduate School of Biomedical Sciences, The Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Department of Systems Biology of Disease and Therapeutics, Graduate School of Biomedical Sciences, The Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Dac A. Nguyen
- Division of Nephrology, Department of Medicine and Graduate School of Biomedical Sciences, The Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- NIH Medical Scientist Training Program, The Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Systems Biology of Disease and Therapeutics, Graduate School of Biomedical Sciences, The Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Edgar Leal-Pinto
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Ronald E. Gordon
- Department of Pathology, The Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Basil Hanss
- Division of Nephrology, Department of Medicine and Graduate School of Biomedical Sciences, The Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
26
|
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]
|
27
|
Nano bioresearch approach by microtechnology. Drug Discov Today 2013; 18:552-9. [PMID: 23402847 DOI: 10.1016/j.drudis.2013.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2012] [Revised: 12/15/2012] [Accepted: 02/01/2013] [Indexed: 11/20/2022]
Abstract
To progress in basic science and drug development, convenient methodology for detecting specific biological molecules and their interaction in living organism is in high demand. After more than 20 years of increasing research efforts, micro and nanotechnologies are now mature to propose a new class of miniature devices and principles enabling compartmentalized bioassays. Among them, this review proposes various examples that include array of electro-active microwells for highly parallel single cell analysis, cost-effective nanofluidic for DNA separation, parallel enzymatic reaction in 100pL droplet and high-throughput platform for membrane proteins assays. The micro devices are presented with relevant experiments to foresee their future contribution to translational research and drug discovery.
Collapse
|
28
|
Shim JS, Geng J, Ahn CH, Guo P. Formation of lipid bilayers inside microfluidic channel array for monitoring membrane-embedded nanopores of phi29 DNA packaging nanomotor. Biomed Microdevices 2013; 14:921-8. [PMID: 22773160 DOI: 10.1007/s10544-012-9671-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An efficient method to form lipid bilayers inside an array of microfluidic channels has been developed and applied to monitor the membrane-embedded phi29 DNA packaging motor with an electrochemical characterization on a lab-on-a-chip (LOC) platform. A push-pull junction capturing approach was applied to confine a small amount of the lipid solution inside a microchannel. The selective permeability between solvents and water in PDMS was utilized to extract the solvent from the lipid solution, resulting in a self-formation of the lipid bilayer in the microchannel array. Each microchannel was independently connected to a silver/silver chloride (Ag/AgCl) electrode array, leading to a high-throughput monitoring of the nanopore insertion in the formed lipid bilayers. The formation of multiple lipid bilayers inside an array of microchannels and the simultaneous electrical and optical monitoring of multiple bilayer provides an efficient LOC platform for the further development of single phi29 motor pore sensing and high throughput single pore dsDNA sequencing.
Collapse
Affiliation(s)
- Joon S Shim
- College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH 45221, USA
| | | | | | | |
Collapse
|
29
|
Friddin MS, Smithers NP, Beaugrand M, Marcotte I, Williamson PTF, Morgan H, de Planque MRR. Single-channel electrophysiology of cell-free expressed ion channels by direct incorporation in lipid bilayers. Analyst 2013; 138:7294-8. [DOI: 10.1039/c3an01540h] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
|
30
|
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.
Collapse
|
31
|
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.
Collapse
Affiliation(s)
- Ahmad M El-Arabi
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | | | | |
Collapse
|
32
|
Castell OK, Berridge J, Wallace MI. Quantification of Membrane Protein Inhibition by Optical Ion Flux in a Droplet Interface Bilayer Array. Angew Chem Int Ed Engl 2012; 51:3134-8. [DOI: 10.1002/anie.201107343] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 01/24/2012] [Indexed: 01/01/2023]
|
33
|
Castell OK, Berridge J, Wallace MI. Quantification of Membrane Protein Inhibition by Optical Ion Flux in a Droplet Interface Bilayer Array. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
34
|
Steller L, Kreir M, Salzer R. Natural and artificial ion channels for biosensing platforms. Anal Bioanal Chem 2011; 402:209-30. [PMID: 22080413 DOI: 10.1007/s00216-011-5517-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 10/14/2011] [Accepted: 10/18/2011] [Indexed: 10/15/2022]
Abstract
The single-molecule selectivity and specificity of the binding process together with the expected intrinsic gain factor obtained when utilizing flow through a channel have attracted the attention of analytical chemists for two decades. Sensitive and selective ion channel biosensors for high-throughput screening are having an increasing impact on modern medical care, drug screening, environmental monitoring, food safety, and biowarefare control. Even virus antigens can be detected by ion channel biosensors. The study of ion channels and other transmembrane proteins is expected to lead to the development of new medications and therapies for a wide range of illnesses. From the first attempts to use membrane proteins as the receptive part of a sensor, ion channels have been engineered as chemical sensors. Several other types of peptidic or nonpeptidic channels have been investigated. Various gating mechanisms have been implemented in their pores. Three technical problems had to be solved to achieve practical biosensors based on ion channels: the fabrication of stable lipid bilayer membranes, the incorporation of a receptor into such a structure, and the marriage of the modified membrane to a transducer. The current status of these three areas of research, together with typical applications of ion-channel biosensors, are discussed in this review.
Collapse
Affiliation(s)
- L Steller
- Department of Magnetic and Acoustic Resonances, Leibniz Institute for Solid State and Materials Research, Dresden, Germany.
| | | | | |
Collapse
|
35
|
Baaken G, Ankri N, Schuler AK, Rühe J, Behrends JC. Nanopore-based single-molecule mass spectrometry on a lipid membrane microarray. ACS NANO 2011; 5:8080-8. [PMID: 21932787 DOI: 10.1021/nn202670z] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We report on parallel high-resolution electrical single-molecule analysis on a chip-based nanopore microarray. Lipid bilayers of <20 μm diameter containing single alpha-hemolysin pores were formed on arrays of subpicoliter cavities containing individual microelectrodes (microelectrode cavity array, MECA), and ion conductance-based single molecule mass spectrometry was performed on mixtures of poly(ethylene glycol) molecules of different length. We thereby demonstrate the function of the MECA device as a chip-based platform for array-format nanopore recordings with a resolution at least equal to that of established single microbilayer supports. We conclude that devices based on MECAs may enable more widespread analytical use of nanopores by providing the high throughput and ease of operation of a high-density array format while maintaining or exceeding the precision of state-of-the-art microbilayer recordings.
Collapse
Affiliation(s)
- Gerhard Baaken
- Laboratory for Electrophysiology and Biotechnology, Department of Physiology, University of Freiburg, Hermann-Herder-Strasse 7, 79104 Freiburg, Germany
| | | | | | | | | |
Collapse
|
36
|
Portonovo SA, Schmidt J. Masking apertures enabling automation and solution exchange in sessile droplet lipid bilayers. Biomed Microdevices 2011; 14:187-91. [DOI: 10.1007/s10544-011-9596-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
37
|
Jung SH, Choi S, Kim YR, Jeon TJ. Storable droplet interface lipid bilayers for cell-free ion channel studies. Bioprocess Biosyst Eng 2011; 35:241-6. [PMID: 21909672 DOI: 10.1007/s00449-011-0602-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/16/2011] [Indexed: 11/24/2022]
Abstract
An artificially created lipid bilayer is an important platform in studying ion channels and engineered biosensor applications. However, a lipid bilayer created using conventional techniques is fragile and short-lived, and the measurement of ion channels requires expertise and laborious procedures, precluding practical applications. Here, we demonstrate a storable droplet lipid bilayer precursor frozen with ion channels, resulting in a droplet interface bilayer upon thawing. A small vial with an aqueous droplet in organic solution was flash frozen in -80 °C methanol immediately after an aqueous droplet was introduced into the organic solution and gravity draws the droplet down to the interface upon thawing. A lipid bilayer created along the interface using this method had giga-ohm resistance and typical specific capacitance values. The noise level of this system is favorably comparable to the conventional system. The subsequent incorporation of ion channels, alpha-hemolysin and gramicidin A, showed typical conductance values consistent with those in previous literatures. This novel system to create a lipid bilayer as a whole can be automated from its manufacture to use and indefinitely stored when frozen. As a result, ion channel measurements can be carried out in any place, increasing the accessibility of ion channel studies as well as a number of applications, such as biosensors, ion channel drug screening, and biophysical studies.
Collapse
Affiliation(s)
- Sung-Ho Jung
- Department of Biological Engineering, Inha University, Incheon, Korea
| | | | | | | |
Collapse
|
38
|
Self-Assembly in Micro- and Nanofluidic Devices: A Review of Recent Efforts. MICROMACHINES 2011. [DOI: 10.3390/mi2010017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
39
|
Thapliyal T, Poulos JL, Schmidt JJ. Automated lipid bilayer and ion channel measurement platform. Biosens Bioelectron 2011; 26:2651-4. [DOI: 10.1016/j.bios.2010.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 01/16/2010] [Accepted: 01/19/2010] [Indexed: 10/19/2022]
|
40
|
Poulos JL, Portonovo SA, Bang H, Schmidt JJ. Automatable lipid bilayer formation and ion channel measurement using sessile droplets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:454105. [PMID: 21339593 DOI: 10.1088/0953-8984/22/45/454105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Artificial lipid bilayer membranes have been used to reconstitute ion channels for scientific and technological applications. Membrane formation has traditionally involved slow, labor intensive processes best suited to small scale laboratory experimentation. We have recently demonstrated a high throughput method of membrane formation using automated liquid-handling robotics. We describe here the integration of membrane formation and measurement with two methods compatible with automation and high throughput liquid-handling robotics. Both of these methods create artificial lipid bilayers by joining lipid monolayers self-assembled at the interface of aqueous and organic phases using sessile aqueous droplets in contact with a measurement electrode; one using a pin tool, commonly employed in high throughput fluid handling assays, and the other using a positive displacement pipette. Membranes formed with both methods were high quality and supported measurement of ion channels at the single molecule level. Full automation of bilayer production and measurement with the positive displacement pipette was demonstrated by integrating it with a motion control platform.
Collapse
|
41
|
Majd S, Yusko EC, Billeh YN, Macrae MX, Yang J, Mayer M. Applications of biological pores in nanomedicine, sensing, and nanoelectronics. Curr Opin Biotechnol 2010; 21:439-76. [PMID: 20561776 PMCID: PMC3121537 DOI: 10.1016/j.copbio.2010.05.002] [Citation(s) in RCA: 239] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 05/03/2010] [Accepted: 05/06/2010] [Indexed: 12/29/2022]
Abstract
Biological protein pores and pore-forming peptides can generate a pathway for the flux of ions and other charged or polar molecules across cellular membranes. In nature, these nanopores have diverse and essential functions that range from maintaining cell homeostasis and participating in cell signaling to activating or killing cells. The combination of the nanoscale dimensions and sophisticated - often regulated - functionality of these biological pores make them particularly attractive for the growing field of nanobiotechnology. Applications range from single-molecule sensing to drug delivery and targeted killing of malignant cells. Potential future applications may include the use of nanopores for single strand DNA sequencing and for generating bio-inspired, and possibly, biocompatible visual detection systems and batteries. This article reviews the current state of applications of pore-forming peptides and proteins in nanomedicine, sensing, and nanoelectronics.
Collapse
Affiliation(s)
- Sheereen Majd
- Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, Michigan 48109-2110, USA
| | | | | | | | | | | |
Collapse
|
42
|
Studer A, Demarche S, Langenegger D, Tiefenauer L. Integration and recording of a reconstituted voltage-gated sodium channel in planar lipid bilayers. Biosens Bioelectron 2010; 26:1924-8. [PMID: 20609576 DOI: 10.1016/j.bios.2010.06.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 06/07/2010] [Accepted: 06/07/2010] [Indexed: 11/29/2022]
Abstract
Functional assays for membrane proteins become increasingly important in biosciences. We demonstrate the integration of reconstituted bacterial voltage-gated sodium channels (NaChBac) into preformed free-standing lipid bilayers by using the nystatin-ergosterol method to promote proteoliposome fusion. Vesicle delivery and subsequent NaChBac activity were monitored, the orientation of the transferred ion channels was assessed measuring at both, positive and negative holding potentials and the channel specificity was demonstrated by adding the blocker nimodipine. A conductance of 120 pS per channel and an opening time in the range of seconds have been observed. Interestingly, we found that fusion of proteoliposomes into preformed free-standing bilayers is limited, if hydrophobically silanized silicon nitride membranes are used as the supporting material. In this case the diameter of the liposome had to be at least 20 times smaller compared to that of the pore to render fusion possible.
Collapse
Affiliation(s)
- A Studer
- Paul Scherrer Institut, Department of Biology and Chemistry, Biomolecular Research Laboratory, CH-5232 Villigen PSI, Switzerland.
| | | | | | | |
Collapse
|
43
|
Sarles SA, Leo DJ. Regulated attachment method for reconstituting lipid bilayers of prescribed size within flexible substrates. Anal Chem 2010; 82:959-66. [PMID: 20058855 DOI: 10.1021/ac902555z] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new method called the regulated attachment method (RAM) for reproducibly forming lipid bilayers within flexible substrates has been developed that enables precise control over the size of the bilayer. This technique uses a deformable flexible substrate to open and close an aperture that subdivides aqueous volumes submersed in an organic solvent. Phospholipids incorporated as vesicles in the aqueous phase self-assemble at the oil/water interface to form lipid monolayers that encapsulate each aqueous volume. Controlled attachment of opposing lipid monolayers is achieved by regulating the dimensions of the aperture in the substrate that separates the adjacent aqueous volumes. In this manner, the size of a lipid bilayer formed within a flexible substrate is a function of the substrate and aperture dimensions, and not determined by the sizes or shapes of the aqueous volumes. Lipid bilayers formed within the prototype flexible substrate exhibit DC resistances consistently higher than 10 GOmega and can survive 20-30x changes in area without rupture. Furthermore, RAM permits lipid bilayers to be completely unzipped after thinning by applying sufficient force to fully close the dividing aperture and even allows the introduction of species, such as alamethicin channels, into preformed lipid bilayers via controlled injection through an intersecting channel within the substrate. Controlling the size of the interface through indirect interactions with the supporting substrate offers a new platform for assembling durable lipid bilayers. We envision that this technology can be scaled to higher dimensions consisting of multiple apertures required for creating aqueous networks partitioned by functional lipid bilayers and to smaller length scales to produce very small lipid bilayers capable of hosting single proteins.
Collapse
Affiliation(s)
- Stephen A Sarles
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, USA
| | | |
Collapse
|
44
|
Stanley CE, Elvira KS, Niu XZ, Gee AD, Ces O, Edel JB, deMello AJ. A microfluidic approach for high-throughput droplet interface bilayer (DIB) formation. Chem Commun (Camb) 2010; 46:1620-2. [DOI: 10.1039/b924897h] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
45
|
Maglia G, Heron AJ, Hwang WL, Holden MA, Mikhailova E, Li Q, Cheley S, Bayley H. Droplet networks with incorporated protein diodes show collective properties. NATURE NANOTECHNOLOGY 2009; 4:437-40. [PMID: 19581896 DOI: 10.1038/nnano.2009.121] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 04/28/2009] [Indexed: 05/02/2023]
Abstract
Recently, we demonstrated that submicrolitre aqueous droplets submerged in an apolar liquid containing lipid can be tightly connected by means of lipid bilayers to form networks. Droplet interface bilayers have been used for rapid screening of membrane proteins and to form asymmetric bilayers with which to examine the fundamental properties of channels and pores. Networks, meanwhile, have been used to form microscale batteries and to detect light. Here, we develop an engineered protein pore with diode-like properties that can be incorporated into droplet interface bilayers in droplet networks to form devices with electrical properties including those of a current limiter, a half-wave rectifier and a full-wave rectifier. The droplet approach, which uses unsophisticated components (oil, lipid, salt water and a simple pore), can therefore be used to create multidroplet networks with collective properties that cannot be produced by droplet pairs.
Collapse
Affiliation(s)
- Giovanni Maglia
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Bilayer lipid membranes from falling droplets. Anal Bioanal Chem 2009; 393:1601-5. [DOI: 10.1007/s00216-008-2588-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 11/20/2008] [Accepted: 12/17/2008] [Indexed: 11/26/2022]
|