1
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Zhang Y, Riexinger J, Yang X, Mikhailova E, Jin Y, Zhou L, Bayley H. A microscale soft ionic power source modulates neuronal network activity. Nature 2023; 620:1001-1006. [PMID: 37648756 PMCID: PMC10468398 DOI: 10.1038/s41586-023-06295-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/07/2023] [Indexed: 09/01/2023]
Abstract
Bio-integrated devices need power sources to operate1,2. Despite widely used technologies that can provide power to large-scale targets, such as wired energy supplies from batteries or wireless energy transduction3, a need to efficiently stimulate cells and tissues on the microscale is still pressing. The ideal miniaturized power source should be biocompatible, mechanically flexible and able to generate an ionic current for biological stimulation, instead of using electron flow as in conventional electronic devices4-6. One approach is to use soft power sources inspired by the electrical eel7,8; however, power sources that combine the required capabilities have not yet been produced, because it is challenging to obtain miniaturized units that both conserve contained energy before usage and are easily triggered to produce an energy output. Here we develop a miniaturized soft power source by depositing lipid-supported networks of nanolitre hydrogel droplets that use internal ion gradients to generate energy. Compared to the original eel-inspired design7, our approach can shrink the volume of a power unit by more than 105-fold and it can store energy for longer than 24 h, enabling operation on-demand with a 680-fold greater power density of about 1,300 W m-3. Our droplet device can serve as a biocompatible and biological ionic current source to modulate neuronal network activity in three-dimensional neural microtissues and in ex vivo mouse brain slices. Ultimately, our soft microscale ionotronic device might be integrated into living organisms.
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Affiliation(s)
- Yujia Zhang
- Department of Chemistry, University of Oxford, Oxford, UK.
| | | | - Xingyun Yang
- Department of Chemistry, University of Oxford, Oxford, UK
| | | | - Yongcheng Jin
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Linna Zhou
- Department of Chemistry, University of Oxford, Oxford, UK.
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, Oxford, UK.
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2
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Hartmann D, Chowdhry R, Smith JM, Booth MJ. Orthogonal Light-Activated DNA for Patterned Biocomputing within Synthetic Cells. J Am Chem Soc 2023; 145:9471-9480. [PMID: 37125650 PMCID: PMC10161232 DOI: 10.1021/jacs.3c02350] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Cell-free gene expression is a vital research tool to study biological systems in defined minimal environments and has promising applications in biotechnology. Developing methods to control DNA templates for cell-free expression will be important for precise regulation of complex biological pathways and use with synthetic cells, particularly using remote, nondamaging stimuli such as visible light. Here, we have synthesized blue light-activatable DNA parts that tightly regulate cell-free RNA and protein synthesis. We found that this blue light-activated DNA could initiate expression orthogonally to our previously generated ultraviolet (UV) light-activated DNA, which we used to generate a dual-wavelength light-controlled cell-free AND-gate. By encapsulating these orthogonal light-activated DNAs into synthetic cells, we used two overlapping patterns of blue and UV light to provide precise spatiotemporal control over the logic gate. Our blue and UV orthogonal light-activated DNAs will open the door for precise control of cell-free systems in biology and medicine.
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Affiliation(s)
- Denis Hartmann
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Razia Chowdhry
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Jefferson M Smith
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Michael J Booth
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K
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3
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Koner S, Tawfik J, Mashali F, Kennison KB, McClintic WT, Heberle FA, Tu YM, Kumar M, Sarles SA. Homogeneous hybrid droplet interface bilayers assembled from binary mixtures of DPhPC phospholipids and PB-b-PEO diblock copolymers. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183997. [PMID: 35718208 DOI: 10.1016/j.bbamem.2022.183997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 06/09/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Hybrid membranes built from phospholipids and amphiphilic block copolymers seek to capitalize on the benefits of both constituents for constructing biomimetic interfaces with improved performance. However, hybrid membranes have not been formed or studied using the droplet interface bilayer (DIB) method, an approach that offers advantages for revealing nanoscale changes in membrane structure and mechanics and offers a path toward assembling higher-order tissues. We report on hybrid droplet interface bilayers (hDIBs) formed in hexadecane from binary mixtures of synthetic diphytanoyl phosphatidylcholine (DPhPC) lipids and low molecular weight 1,2 polybutadiene-b-polyethylene oxide (PBPEO) amphiphilic block copolymers and use electrophysiology measurements and imaging to assess the effects of PBPEO in the membrane. This work reveals that hDIBs containing up to 15 mol% PBPEO plus DPhPC are homogeneously mixtures of lipids and polymers, remain highly resistive to ion transport, and are stable-including under applied voltage. Moreover, they exhibit hydrophobic thicknesses similar to DPhPC-only bilayers, but also have significantly lower values of membrane tension. These characteristics coincide with reduced energy of adhesion between droplets and the formation of alamethicin ion channels at significantly lower threshold voltages, demonstrating that even moderate amounts of amphiphilic block copolymers in a lipid bilayer provide a route for tuning the physical properties of a biomimetic membrane.
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Affiliation(s)
- Subhadeep Koner
- Department of Mechanical Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Joseph Tawfik
- Department of Mechanical Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Farzin Mashali
- Department of Mechanical Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Kristen B Kennison
- Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA
| | | | | | - Yu-Ming Tu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Manish Kumar
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, USA; Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Stephen A Sarles
- Department of Mechanical Aerospace and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996, USA.
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4
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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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5
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Makhoul-Mansour MM, Challita EJ, Chaurasia A, Leo DJ, Sukharev S, Freeman EC. A skin-inspired soft material with directional mechanosensation. BIOINSPIRATION & BIOMIMETICS 2021; 16:046014. [PMID: 33848998 DOI: 10.1088/1748-3190/abf746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 04/13/2021] [Indexed: 06/12/2023]
Abstract
Lessons about artificial sensor design may be taken from evolutionarily perfected physiological systems. Mechanosensory cells in human skin are exquisitely sensitive to gentle touch and enable us to distinguish objects of different stiffnesses and textures. These cells are embedded in soft epidermal layers of gel-like consistency. Reproducing these mechanosensing capabilities in new soft materials may lead to the development of adaptive mechanosensors which will further enhance the abilities of engineered membrane-based structures with bioinspired sensing strategies. This strategy is explored here using droplet interface bilayers embedded within a thermoreversible organogel. The interface between two lipid-coated aqueous inclusions contained within a soft polymeric matrix forms a lipid bilayer resembling the lipid matrix of cell membranes. These interfaces are functionalized with bacterial mechanosensitive channels (V23T MscL) which convert membrane tension into changes in membrane conductance, mimicking mechanosensitive channel activation in mammalian mechanosensory cells. The distortion of encapsulated adhered droplets by cyclical external forces are first explored using a finite element composite model illustrating the directional propagation of mechanical disturbances imposed by a piston. The model predicts that the orientation of the droplet pair forming the membrane relative to the direction of the compression plays a role in the membrane response. The directional dependence of mechanosensitive channel activation in response to gel compression is confirmed experimentally and shows that purely compressive perturbations normal to the interface invoke different channel activities as compared to shearing displacement along a plane of the membrane. The developed system containing specially positioned pairs of droplets functionalized with bacterial mechanosensitive channels and embedded in a gel creates a skin-inspired soft material with a directional response to mechanical perturbation.
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Affiliation(s)
| | - Elio J Challita
- College of Engineering, University of Georgia, Athens, GA, United States of America
- George W. Woodruff School of Mechanical Engineering, Georgia Tech, Atlanta, GA, United States of America
- School of Chemical & Biomolecular Engineering, Georgia Tech, Atlanta, GA, United States of America
| | | | - Donald J Leo
- College of Engineering, University of Georgia, Athens, GA, United States of America
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, MD, United States of America
| | - Eric C Freeman
- College of Engineering, University of Georgia, Athens, GA, United States of America
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6
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Makhoul-Mansour MM, Freeman EC. Droplet-Based Membranous Soft Materials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3231-3247. [PMID: 33686860 DOI: 10.1021/acs.langmuir.0c03289] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Inspired by the structure and functionality of natural cellular tissues, droplet interface bilayer (DIB)-based materials strategically combine model membrane assembly techniques and droplet microfluidics. These structures have shown promising results in applications ranging from biological computing to chemical microrobots. This Feature Article briefly explores recent advances in the areas of construction, manipulation, and functionalization of DIB networks; discusses their unique mechanics; and focuses on the contributions of our lab in the advancement of this platform. We also reflect on some of the limitations facing DIB-based materials and how they might be addressed, highlighting promising applications made possible through the refinement of the material concept.
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Affiliation(s)
- Michelle M Makhoul-Mansour
- School of Environmental, Civil, Agricultural and Mechanical Engineering, University of Georgia, Athens, Georgia 30602, United States
| | - Eric C Freeman
- School of Environmental, Civil, Agricultural and Mechanical Engineering, University of Georgia, Athens, Georgia 30602, United States
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7
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Ito Y, Izawa Y, Osaki T, Kamiya K, Misawa N, Fujii S, Mimura H, Miki N, Takeuchi S. A Lipid-Bilayer-On-A-Cup Device for Pumpless Sample Exchange. MICROMACHINES 2020; 11:mi11121123. [PMID: 33352964 PMCID: PMC7767076 DOI: 10.3390/mi11121123] [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: 11/30/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 01/12/2023]
Abstract
Lipid-bilayer devices have been studied for on-site sensors in the fields of diagnosis, food and environmental monitoring, and safety/security inspection. In this paper, we propose a lipid-bilayer-on-a-cup device for serial sample measurements using a pumpless solution exchange procedure. The device consists of a millimeter-scale cylindrical cup with vertical slits which is designed to steadily hold an aqueous solution and exchange the sample by simply fusing and splitting the solution with an external solution. The slit design was experimentally determined by the capabilities of both the retention and exchange of the solution. Using the optimized slit, a planar lipid bilayer was reconstituted with a nanopore protein at a microaperture allocated to the bottom of the cup, and the device was connected to a portable amplifier. The solution exchangeability was demonstrated by observing the dilution process of a blocker molecule of the nanopore dissolved in the cup. The pumpless solution exchange by the proposed cup-like device presents potential as a lipid-bilayer system for portable sensing applications.
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Affiliation(s)
- Yoshihisa Ito
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
- School of Integrated Design Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Yusuke Izawa
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
- School of Integrated Design Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Toshihisa Osaki
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Koki Kamiya
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
| | - Nobuo Misawa
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
| | - Satoshi Fujii
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
| | - Hisatoshi Mimura
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
| | - Norihisa Miki
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
- Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Shoji Takeuchi
- Artificial Cell Membrane Systems Group, Kanagawa Institute of Industrial Science and Technology, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan; (Y.I.); (Y.I.); (T.O.); (K.K.); (N.M.); (S.F.); (H.M.); (N.M.)
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
- 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
- Correspondence: ; Tel.: +81-3-5841-7056; Fax: +81-3-5841-7104
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8
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Ohashi T, Kuyama H. Magnetic particle transport through organogel - an application to DNA extraction. Anal Biochem 2020; 611:113932. [PMID: 32891594 DOI: 10.1016/j.ab.2020.113932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/18/2020] [Accepted: 08/26/2020] [Indexed: 12/23/2022]
Abstract
An observation that magnetic particles are transported through organogel encouraged us to investigate its feasibility of liquid-phase displacement in DNA extraction using magnetic particles. Organogel for this study was prepared from a gelator, 12-hydroxystearic acid (12-HSA), and an apolar solvent, methylphenylsilicone oil. The organogel is a gel-like solid material with hydrophobic and elastic properties. These properties, hydrophobicity, and elasticity were demonstrated to be advantageous for liquid compartmentalization and efficient liquid-phase displacement. The extracted DNA with using the organogel device was successfully detected off-chip by conventional real-time PCR.
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Affiliation(s)
- Tetsuo Ohashi
- Technology Research Laboratory, Shimadzu Corporation, 3-9-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto, 619-0237, Japan.
| | - Hiroki Kuyama
- Technology Research Laboratory, Shimadzu Corporation, 3-9-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto, 619-0237, Japan
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9
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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.
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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
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10
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Nau M, Trosien S, Seelinger D, Boehm AK, Biesalski M. Spatially Resolved Crosslinking of Hydroxypropyl Cellulose Esters for the Generation of Functional Surface-Attached Organogels. Front Chem 2019; 7:367. [PMID: 31179272 PMCID: PMC6543898 DOI: 10.3389/fchem.2019.00367] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/03/2019] [Indexed: 11/13/2022] Open
Abstract
Chemistry, geometric shape and swelling behavior are the key parameters that determine any successful use of man-made polymeric networks (gels). While understanding of the swelling behavior of both water-swellable hydrogels and organogels that swell in organic solvents can be considered well-advanced with respect to fossil fuel-based polymer networks, the understanding, in particular, of wood-derived polymers in such a network architecture is still lacking. In this work, we focus on organogels derived from hydroxypropyl cellulose (HPC) ester. The latter polymer was functionalized with saturated and unsaturated fatty acids, respectively. Due to their tailored chemical constitution, we demonstrated that such polysaccharide can be crosslinked and simultaneously surface-bound by using a photo-induced radical reaction using a photo-initiator. Based on the choice of fatty acid used in the design of the HPC ester, and by controlling the degree of substitution (DS) obtained during the esterification of the polysaccharide, modular manipulation of the physical properties (e.g., polarity) of the resulting gel is possible. Depending on the initiator employed, different wavelengths of light, from UV to visible, can be utilized for the crosslinking reaction, which facilitates the deployment of a range of light sources and different lithographic methods. Additionally, we showed that altering of the illumination time allows to tailor the netpoint density, and thus, the degree of linear deformation in equilibrium and the swelling kinetics. Finally, we performed a proof-of-principle experiment to demonstrate the application of our material for the generation of spatially resolved polymer patches to enrich organic molecules from a solution within a microfluidic channel.
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Affiliation(s)
| | | | | | | | - Markus Biesalski
- Laboratory of Macromolecular Chemistry and Paper Chemistry, Ernst-Berl Institute of Chemistry, Technische Universität Darmstadt, Darmstadt, Germany
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11
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Challita EJ, Freeman EC. Hydrogel Microelectrodes for the Rapid, Reliable, and Repeatable Characterization of Lipid Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:15166-15173. [PMID: 30468580 DOI: 10.1021/acs.langmuir.8b02867] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Model lipid bilayer membranes provide approximations of natural cellular membranes that may be formed in the laboratory to study their mechanics and interactions with the surrounding environment. A new approach for their formation is proposed here based on the self-assembly of lipid monolayers at oil-water interfaces, creating a lipid-coated hydrogel-tipped electrode that produces a stable lipid membrane on the surface when introduced to a lipid-coated aqueous droplet. Membrane formation using the hydrogel microelectrode is tested for a variety of lipids and oils. The channel-forming peptide alamethicin is added to the membrane, and its functionality is verified. Finally, asymmetric membranes are created using varying lipid compositions, and the capacity for repeated quantification of membrane structure is demonstrated. The proposed hydrogel microelectrodes are compatible with multiple oils and lipids, simple to use, and suitable for detecting the presence of both biomolecular transporters and dissolved lipid compositions within aqueous droplets.
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Affiliation(s)
- Elio J Challita
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, College of Engineering , University of Georgia , 110 Riverbend Road , Athens , Georgia 30605 , United States
| | - Eric C Freeman
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, College of Engineering , University of Georgia , 110 Riverbend Road , Athens , Georgia 30605 , United States
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12
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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: 42] [Impact Index Per Article: 7.0] [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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13
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Encapsulating Networks of Droplet Interface Bilayers in a Thermoreversible Organogel. Sci Rep 2018; 8:6494. [PMID: 29691447 PMCID: PMC5915452 DOI: 10.1038/s41598-018-24720-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/04/2018] [Indexed: 02/08/2023] Open
Abstract
The development of membrane-based materials that exhibit the range and robustness of autonomic functions found in biological systems remains elusive. Droplet interface bilayers (DIBs) have been proposed as building blocks for such materials, owing to their simplicity, geometry, and capability for replicating cellular phenomena. Similar to how individual cells operate together to perform complex tasks and functions in tissues, networks of functionalized DIBs have been assembled in modular/scalable networks. Here we present the printing of different configurations of picoliter aqueous droplets in a bath of thermoreversible organogel consisting of hexadecane and SEBS triblock copolymers. The droplets are connected by means of lipid bilayers, creating a network of aqueous subcompartments capable of communicating and hosting various types of chemicals and biomolecules. Upon cooling, the encapsulating organogel solidifies to form self-supported liquid-in-gel, tissue-like materials that are robust and durable. To test the biomolecular networks, we functionalized the network with alamethicin peptides and alpha-hemolysin (αHL) channels. Both channels responded to external voltage inputs, indicating the assembly process does not damage the biomolecules. Moreover, we show that the membrane properties may be regulated through the deformation of the surrounding gel.
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14
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Venkatesan GA, Taylor GJ, Basham CM, Brady NG, Collier CP, Sarles SA. Evaporation-induced monolayer compression improves droplet interface bilayer formation using unsaturated lipids. BIOMICROFLUIDICS 2018; 12:024101. [PMID: 29576833 PMCID: PMC5832467 DOI: 10.1063/1.5016523] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/13/2018] [Indexed: 05/25/2023]
Abstract
In this article, we report on a new experimental methodology to enable reliable formation of droplet interface bilayer (DIB) model membranes with two types of unsaturated lipids that have proven difficult for creating stable DIBs. Through the implementation of a simple evaporation technique to condition the spontaneously assembled lipid monolayer around each droplet, we increased the success rates of DIB formation for two distinct unsaturated lipids, namely 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), from less than 10% to near 100%. Separately, using a pendant drop tensiometer, we learned that: (a) DOPC and POPC monolayers do not spontaneously assemble into their tightest possible configurations at an oil-water interface, and (b) reducing the surface area of a water droplet coated with a partially packed monolayer leads to a more tightly packed monolayer with an interfacial tension lower than that achieved by spontaneous assembly alone. We also estimated from Langmuir compression isotherms obtained for both lipids that the brief droplet evaporation procedure prior to DIB formation resulted in a 6%-16% reduction in area per lipid for DOPC and POPC, respectively. Finally, the increased success rates of formation for DOPC and POPC DIBs enabled quantitative characterization of unsaturated lipid membrane properties including electrical resistance, rupture potential, and specific capacitance.
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Affiliation(s)
- Guru A Venkatesan
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | - Colin M Basham
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Nathan G Brady
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
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15
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Booth MJ, Restrepo Schild V, Box SJ, Bayley H. Light-patterning of synthetic tissues with single droplet resolution. Sci Rep 2017; 7:9315. [PMID: 28839174 PMCID: PMC5570938 DOI: 10.1038/s41598-017-09394-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/26/2017] [Indexed: 11/18/2022] Open
Abstract
Synthetic tissues can be generated by forming networks of aqueous droplets in lipid-containing oil. Each droplet contains a cell-free expression system and is connected to its neighbor through a lipid bilayer. In the present work, we have demonstrated precise external control of such networks by activating protein expression within single droplets, by using light-activated DNA to encode either a fluorescent or a pore-forming protein. By controlling the extent of activation, synthetic tissues were generated with graded levels of protein expression in patterns of single droplets. Further, we have demonstrated reversible activation within individual compartments in synthetic tissues by turning a fluorescent protein on-and-off. This is the first example of the high-resolution patterning of droplet networks, following their formation. Single-droplet control will be essential to power subsets of compartments within synthetic tissues or to stimulate subsets of cells when synthetic tissues are interfaced with living tissues.
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Affiliation(s)
- Michael J Booth
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK.
| | | | - Stuart J Box
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Hagan Bayley
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK.
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16
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Bayoumi M, Bayley H, Maglia G, Sapra KT. Multi-compartment encapsulation of communicating droplets and droplet networks in hydrogel as a model for artificial cells. Sci Rep 2017; 7:45167. [PMID: 28367984 PMCID: PMC5377250 DOI: 10.1038/srep45167] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 02/20/2017] [Indexed: 01/20/2023] Open
Abstract
Constructing a cell mimic is a major challenge posed by synthetic biologists. Efforts to this end have been primarily focused on lipid- and polymer-encapsulated containers, liposomes and polymersomes, respectively. Here, we introduce a multi-compartment, nested system comprising aqueous droplets stabilized in an oil/lipid mixture, all encapsulated in hydrogel. Functional capabilities (electrical and chemical communication) were imparted by protein nanopores spanning the lipid bilayer formed at the interface of the encapsulated aqueous droplets and the encasing hydrogel. Crucially, the compartmentalization enabled the formation of two adjoining lipid bilayers in a controlled manner, a requirement for the realization of a functional protocell or prototissue.
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Affiliation(s)
- Mariam Bayoumi
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium
| | - Hagan Bayley
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - Giovanni Maglia
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.,Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - K Tanuj Sapra
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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17
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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
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18
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Baxani DK, Morgan AJL, Jamieson WD, Allender CJ, Barrow DA, Castell OK. Bilayer Networks within a Hydrogel Shell: A Robust Chassis for Artificial Cells and a Platform for Membrane Studies. Angew Chem Int Ed Engl 2016; 55:14240-14245. [PMID: 27726260 PMCID: PMC5129564 DOI: 10.1002/anie.201607571] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Indexed: 11/07/2022]
Abstract
The ability to make artificial lipid bilayers compatible with a wide range of environments, and with sufficient structural rigidity for manual handling, would open up a wealth of opportunities for their more routine use in real‐world applications. Although droplet interface bilayers (DIBs) have been demonstrated in a host of laboratory applications, from chemical logic to biosynthesis reaction vessels, their wider use is hampered by a lack of mechanical stability and the largely manual methods employed in their production. Multiphase microfluidics has enabled us to construct hierarchical triple emulsions with a semipermeable shell, in order to form robust, bilayer‐bound, droplet networks capable of communication with their external surroundings. These constructs are stable in air, water, and oil environments and overcome a critical obstacle of achieving structural rigidity without compromising environmental interaction. This paves the way for practical application of artificial membranes or droplet networks in diverse areas such as medical applications, drug testing, biophysical studies and their use as synthetic cells.
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Affiliation(s)
- Divesh 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
| | - Alex J L Morgan
- School of Engineering, Cardiff University, 14-17 The Parade, CF4 3AA, Cardiff, UK
| | - William 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
| | - Christopher J Allender
- College of Biomedical and Life Sciences, School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, CF10 3NB, Cardiff, UK
| | - David A Barrow
- School of Engineering, Cardiff University, 14-17 The Parade, CF4 3AA, Cardiff, UK
| | - Oliver 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.
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19
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Baxani DK, Morgan AJL, Jamieson WD, Allender CJ, Barrow DA, Castell OK. Bilayer Networks within a Hydrogel Shell: A Robust Chassis for Artificial Cells and a Platform for Membrane Studies. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Divesh 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
| | - Alex J. L. Morgan
- School of Engineering; Cardiff University; 14-17 The Parade CF4 3AA Cardiff UK
| | - William 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
| | - Christopher J. Allender
- College of Biomedical and Life Sciences, School of Pharmacy and Pharmaceutical Sciences; Cardiff University; Redwood Building, King Edward VII Avenue CF10 3NB Cardiff UK
| | - David A. Barrow
- School of Engineering; Cardiff University; 14-17 The Parade CF4 3AA Cardiff UK
| | - Oliver 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
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20
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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.
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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
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