1
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Dimitriou P, Li J, Jamieson WD, Schneider JJ, Castell OK, Barrow DA. Manipulation of encapsulated artificial phospholipid membranes using sub-micellar lysolipid concentrations. Commun Chem 2024; 7:120. [PMID: 38824266 PMCID: PMC11144220 DOI: 10.1038/s42004-024-01209-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/24/2024] [Indexed: 06/03/2024] Open
Abstract
Droplet Interface Bilayers (DIBs) constitute a commonly used model of artificial membranes for synthetic biology research applications. However, their practical use is often limited by their requirement to be surrounded by oil. Here we demonstrate in-situ bilayer manipulation of submillimeter, hydrogel-encapsulated droplet interface bilayers (eDIBs). Monolithic, Cyclic Olefin Copolymer/Nylon 3D-printed microfluidic devices facilitated the eDIB formation through high-order emulsification. By exposing the eDIB capsules to varying lysophosphatidylcholine (LPC) concentrations, we investigated the interaction of lysolipids with three-dimensional DIB networks. Micellar LPC concentrations triggered the bursting of encapsulated droplet networks, while at lower concentrations the droplet network endured structural changes, precisely affecting the membrane dimensions. This chemically-mediated manipulation of enclosed, 3D-orchestrated membrane mimics, facilitates the exploration of readily accessible compartmentalized artificial cellular machinery. Collectively, the droplet-based construct can pose as a chemically responsive soft material for studying membrane mechanics, and drug delivery, by controlling the cargo release from artificial cell chassis.
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Affiliation(s)
- Pantelitsa Dimitriou
- School of Engineering, Cardiff University, Queen's Buildings, Cardiff, CF24 3AA, UK.
| | - Jin Li
- School of Engineering, Cardiff University, Queen's Buildings, Cardiff, CF24 3AA, UK.
| | - William David Jamieson
- School of Pharmacy and Pharmaceutical Sciences, College of Biomedical and Life Sciences, Cardiff University, Redwood Building, Kind Edward VII Avenue, Cardiff, CF10 3NB, UK
| | - Johannes Josef Schneider
- Institute of Applied Mathematics and Physics, School of Engineering, Zurich University of Applied Sciences, Technikumstr. 9, 8401, Winterthur, Switzerland
| | - Oliver Kieran Castell
- School of Pharmacy and Pharmaceutical Sciences, College of Biomedical and Life Sciences, Cardiff University, Redwood Building, Kind Edward VII Avenue, Cardiff, CF10 3NB, UK
| | - David Anthony Barrow
- School of Engineering, Cardiff University, Queen's Buildings, Cardiff, CF24 3AA, UK
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2
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Schafer EA, Maraj JJ, Kenney C, Sarles SA, Rivnay J. Droplet Polymer Bilayers for Bioelectronic Membrane Interfacing. J Am Chem Soc 2024; 146:14391-14396. [PMID: 38748513 DOI: 10.1021/jacs.4c01591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Model membranes interfaced with bioelectronics allow for the exploration of fundamental cell processes and the design of biomimetic sensors. Organic conducting polymers are an attractive surface on which to study the electrical properties of membranes because of their low impedance, high biocompatibility, and hygroscopic nature. However, establishing supported lipid bilayers (SLBs) on conducting polymers has lagged significantly behind other substrate materials, namely, for challenges in membrane electrical sealing and stability. Unlike SLBs that are highly dependent on surface interactions, droplet interface bilayers (DIBs) and droplet hydrogel bilayers (DHBs) leverage the energetically favorable organization of phospholipids at atomically smooth liquid interfaces to build high-integrity membranes. For the first time, we report the formation of droplet polymer bilayers (DPBs) between a lipid-coated aqueous droplet and the high-performing conducting polymer poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS). The resulting bilayers can be produced from a range of lipid compositions and demonstrate strong electrical sealing that outcompetes SLBs. DPBs are subsequently translated to patterned and planar microelectrode arrays to ease barriers to implementation and improve the reliability of membrane formation. This platform enables more reproducible and robust membranes on conducting polymers to further the mission of merging bioelectronics and synthetic, natural, or hybrid bilayer membranes.
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Affiliation(s)
- Emily A Schafer
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Joshua J Maraj
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37916, United States
| | - Camryn Kenney
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, Tennessee 37916, United States
| | - Jonathan Rivnay
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
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3
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Hsu YY, Hwang SW, Chen SJ, Alsberg E, Liu AP. Development of mechanosensitive synthetic cells for biomedical applications. SLAS Technol 2024; 29:100095. [PMID: 37385542 DOI: 10.1016/j.slast.2023.06.004] [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: 04/21/2023] [Revised: 06/08/2023] [Accepted: 06/22/2023] [Indexed: 07/01/2023]
Abstract
The ability of cells to sense and respond to their physical environment plays a fundamental role in a broad spectrum of biological processes. As one of the most essential molecular force sensors and transducers found in cell membranes, mechanosensitive (MS) ion channels can convert mechanical inputs into biochemical or electrical signals to mediate a variety of sensations. The bottom-up construction of cell-sized compartments displaying cell-like organization, behaviors, and complexity, also known as synthetic cells, has gained popularity as an experimental platform to characterize biological functions in isolation. By reconstituting MS channels in the synthetic lipid bilayers, we envision using mechanosensitive synthetic cells for several medical applications. Here, we describe three different concepts for using ultrasound, shear stress, and compressive stress as mechanical stimuli to activate drug release from mechanosensitive synthetic cells for disease treatments.
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Affiliation(s)
- Yen-Yu Hsu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sung-Won Hwang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Samuel J Chen
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Eben Alsberg
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL 60612, USA; Departments of Mechanical & Industrial Engineering, Orthopaedic Surgery, and Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA.
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4
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Escoubet N, Brette R, Pontani LL, Prevost AM. Interaction of the mechanosensitive microswimmer Paramecium with obstacles. ROYAL SOCIETY OPEN SCIENCE 2023; 10:221645. [PMID: 37234495 PMCID: PMC10206458 DOI: 10.1098/rsos.221645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023]
Abstract
In this work, we report investigations of the swimming behaviour of Paramecium tetraurelia, a unicellular microorganism, in micro-engineered pools that are decorated with thousands of cylindrical pillars. Two types of contact interactions are measured, either passive scattering of Paramecium along the obstacle or avoiding reactions (ARs), characterized by an initial backward swimming upon contact, followed by a reorientation before resuming forward motion. We find that ARs are only mechanically triggered approximately 10% of the time. In addition, we observe that only a third of all ARs triggered by contact are instantaneous while two-thirds are delayed by approximately 150 ms. These measurements are consistent with a simple electrophysiological model of mechanotransduction composed of a strong transient current followed by a persistent one upon prolonged contact. This is in apparent contrast with previous electrophysiological measurements where immobilized cells were stimulated with thin probes, which showed instantaneous behavioural responses and no persistent current. Our findings highlight the importance of ecologically relevant approaches to unravel the motility of mechanosensitive microorganisms in complex environments.
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Affiliation(s)
- Nicolas Escoubet
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Jean Perrin, 4 place Jussieu, Paris 75005, France
| | - Romain Brette
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, Paris 75012, France
| | - Lea-Laetitia Pontani
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Jean Perrin, 4 place Jussieu, Paris 75005, France
| | - Alexis Michel Prevost
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, Laboratoire Jean Perrin, 4 place Jussieu, Paris 75005, France
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5
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Tosaka T, Kamiya K. Function Investigations and Applications of Membrane Proteins on Artificial Lipid Membranes. Int J Mol Sci 2023; 24:ijms24087231. [PMID: 37108393 PMCID: PMC10138308 DOI: 10.3390/ijms24087231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Membrane proteins play an important role in key cellular functions, such as signal transduction, apoptosis, and metabolism. Therefore, structural and functional studies of these proteins are essential in fields such as fundamental biology, medical science, pharmacology, biotechnology, and bioengineering. However, observing the precise elemental reactions and structures of membrane proteins is difficult, despite their functioning through interactions with various biomolecules in living cells. To investigate these properties, methodologies have been developed to study the functions of membrane proteins that have been purified from biological cells. In this paper, we introduce various methods for creating liposomes or lipid vesicles, from conventional to recent approaches, as well as techniques for reconstituting membrane proteins into artificial membranes. We also cover the different types of artificial membranes that can be used to observe the functions of reconstituted membrane proteins, including their structure, number of transmembrane domains, and functional type. Finally, we discuss the reconstitution of membrane proteins using a cell-free synthesis system and the reconstitution and function of multiple membrane proteins.
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Affiliation(s)
- Toshiyuki Tosaka
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Gunma 376-8515, Japan
| | - Koki Kamiya
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, Gunma 376-8515, Japan
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6
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Abstract
Plasma membrane tension functions as a global physical organizer of cellular activities. Technical limitations of current membrane tension measurement techniques have hampered in-depth investigation of cellular membrane biophysics and the role of plasma membrane tension in regulating cellular processes. Here, we develop an optical membrane tension reporter by repurposing an E. coli mechanosensitive channel via insertion of circularly permuted GFP (cpGFP), which undergoes a large conformational rearrangement associated with channel activation and thus fluorescence intensity changes under increased membrane tension.
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Affiliation(s)
- Yen-Yu Hsu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Agnes M Resto Irizarry
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jianping Fu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Cell & Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan 48109, United States
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7
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Go S, Eun Suk M. Stretch-activated ionic currents through Ti3C2(OH)2 MXene nanopores. Electrochem commun 2023. [DOI: 10.1016/j.elecom.2023.107434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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8
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Li J, Jamieson WD, Dimitriou P, Xu W, Rohde P, Martinac B, Baker M, Drinkwater BW, Castell OK, Barrow DA. Building programmable multicompartment artificial cells incorporating remotely activated protein channels using microfluidics and acoustic levitation. Nat Commun 2022; 13:4125. [PMID: 35840619 PMCID: PMC9287423 DOI: 10.1038/s41467-022-31898-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 07/06/2022] [Indexed: 01/25/2023] Open
Abstract
Intracellular compartments are functional units that support the metabolism within living cells, through spatiotemporal regulation of chemical reactions and biological processes. Consequently, as a step forward in the bottom-up creation of artificial cells, building analogous intracellular architectures is essential for the expansion of cell-mimicking functionality. Herein, we report the development of a droplet laboratory platform to engineer complex emulsion-based, multicompartment artificial cells, using microfluidics and acoustic levitation. Such levitated models provide free-standing, dynamic, definable droplet networks for the compartmentalisation of chemical species. Equally, they can be remotely operated with pneumatic, heating, and magnetic elements for post-processing, including the incorporation of membrane proteins; alpha-hemolysin; and mechanosensitive channel of large-conductance. The assembly of droplet networks is three-dimensionally patterned with fluidic input configurations determining droplet contents and connectivity, whilst acoustic manipulation can be harnessed to reconfigure the droplet network in situ. The mechanosensitive channel can be repeatedly activated and deactivated in the levitated artificial cell by the application of acoustic and magnetic fields to modulate membrane tension on demand. This offers possibilities beyond one-time chemically mediated activation to provide repeated, non-contact, control of membrane protein function. Collectively, this expands our growing capability to program and operate increasingly sophisticated artificial cells as life-like materials.
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Affiliation(s)
- Jin Li
- School of Engineering, Cardiff University, The Parade, Cardiff, CF24 3AA, UK.
| | - William D Jamieson
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Ave, Cardiff, CF10 3NB, UK
| | | | - Wen Xu
- Cardiff Business School, Cardiff University, Aberconway Building, Colum Dr, Cardiff, CF10 3EU, UK
| | - Paul Rohde
- Victor Chang Cardiac Research Institute, Lowy Packer Building, 405 Liverpool St, Darlinhurst, NSW, 2010, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Lowy Packer Building, 405 Liverpool St, Darlinhurst, NSW, 2010, Australia.,School of Clinical Medicine, UNSW, Sydney, NSW, 2052, Australia
| | - Matthew Baker
- School of Biotechnology and Biomolecular Science, UNSW, Sydney, NSW, 2052, Australia
| | - Bruce W Drinkwater
- Department of Mechanical Engineering, University of Bristol, University Walk, Bristol, BS8 1TR, UK.
| | - Oliver K Castell
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, King Edward VII Ave, Cardiff, CF10 3NB, UK.
| | - David A Barrow
- School of Engineering, Cardiff University, The Parade, Cardiff, CF24 3AA, UK.
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9
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Bavi O, Zhou Z, Bavi N, Mehdi Vaez Allaei S, Cox CD, Martinac B. Asymmetric effects of amphipathic molecules on mechanosensitive channels. Sci Rep 2022; 12:9976. [PMID: 35705645 PMCID: PMC9200802 DOI: 10.1038/s41598-022-14446-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/06/2022] [Indexed: 12/30/2022] Open
Abstract
Mechanosensitive (MS) ion channels are primary transducers of mechanical force into electrical and/or chemical intracellular signals. Many diverse MS channel families have been shown to respond to membrane forces. As a result of this intimate relationship with the membrane and proximal lipids, amphipathic compounds exert significant effects on the gating of MS channels. Here, we performed all-atom molecular dynamics (MD) simulations and employed patch-clamp recording to investigate the effect of two amphipaths, Fluorouracil (5-FU) a chemotherapy agent, and the anaesthetic trifluoroethanol (TFE) on structurally distinct mechanosensitive channels. We show that these amphipaths have a profound effect on the bilayer order parameter as well as transbilayer pressure profile. We used bacterial mechanosensitive channels (MscL/MscS) and a eukaryotic mechanosensitive channel (TREK-1) as force-from-lipids reporters and showed that these amphipaths have differential effects on these channels depending on the amphipaths' size and shape as well as which leaflet of the bilayer they incorporate into. 5-FU is more asymmetric in shape and size than TFE and does not penetrate as deep within the bilayer as TFE. Thereby, 5-FU has a more profound effect on the bilayer and channel activity than TFE at much lower concentrations. We postulate that asymmetric effects of amphipathic molecules on mechanosensitive membrane proteins through the bilayer represents a general regulatory mechanism for these proteins.
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Affiliation(s)
- Omid Bavi
- grid.444860.a0000 0004 0600 0546Department of Mechanical and Aerospace Engineering, Shiraz University of Technology, Shiraz, Iran
| | - Zijing Zhou
- grid.1057.30000 0000 9472 3971Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010 Australia
| | - Navid Bavi
- grid.170205.10000 0004 1936 7822Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL USA
| | - S. Mehdi Vaez Allaei
- grid.46072.370000 0004 0612 7950Department of Physics, University of Tehran, 1439955961 Tehran, Iran
| | - Charles D. Cox
- grid.1057.30000 0000 9472 3971Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010 Australia ,grid.1005.40000 0004 4902 0432Faculty of Medicine, St Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW 2010 Australia
| | - B. Martinac
- grid.1057.30000 0000 9472 3971Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010 Australia ,grid.1005.40000 0004 4902 0432Faculty of Medicine, St Vincent’s Clinical School, University of New South Wales, Darlinghurst, NSW 2010 Australia
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10
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Enhancing membrane-based soft materials with magnetic reconfiguration events. Sci Rep 2022; 12:1703. [PMID: 35105905 PMCID: PMC8807651 DOI: 10.1038/s41598-022-05501-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 01/12/2022] [Indexed: 11/08/2022] Open
Abstract
Adaptive and bioinspired droplet-based materials are built using the droplet interface bilayer (DIB) technique, assembling networks of lipid membranes through adhered microdroplets. The properties of these lipid membranes are linked to the properties of the droplets forming the interface. Consequently, rearranging the relative positions of the droplets within the network will also alter the properties of the lipid membranes formed between them, modifying the transmembrane exchanges between neighboring compartments. In this work, we achieved this through the use of magnetic fluids or ferrofluids selectively dispersed within the droplet-phase of DIB structures. First, the ferrofluid DIB properties are optimized for reconfiguration using a coupled experimental-computational approach, exploring the ideal parameters for droplet manipulation through magnetic fields. Next, these findings are applied towards larger, magnetically-heterogeneous collections of DIBs to investigate magnetically-driven reconfiguration events. Activating electromagnets bordering the DIB networks generates rearrangement events by separating and reforming the interfacial membranes bordering the dispersed magnetic compartments. These findings enable the production of dynamic droplet networks capable of modifying their underlying membranous architecture through magnetic forces.
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11
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Sharma B, Moghimianavval H, Hwang SW, Liu AP. Synthetic Cell as a Platform for Understanding Membrane-Membrane Interactions. MEMBRANES 2021; 11:912. [PMID: 34940413 PMCID: PMC8706075 DOI: 10.3390/membranes11120912] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/10/2021] [Accepted: 11/16/2021] [Indexed: 01/27/2023]
Abstract
In the pursuit of understanding life, model membranes made of phospholipids were envisaged decades ago as a platform for the bottom-up study of biological processes. Micron-sized lipid vesicles have gained great acceptance as their bilayer membrane resembles the natural cell membrane. Important biological events involving membranes, such as membrane protein insertion, membrane fusion, and intercellular communication, will be highlighted in this review with recent research updates. We will first review different lipid bilayer platforms used for incorporation of integral membrane proteins and challenges associated with their functional reconstitution. We next discuss different methods for reconstitution of membrane fusion and compare their fusion efficiency. Lastly, we will highlight the importance and challenges of intercellular communication between synthetic cells and synthetic cells-to-natural cells. We will summarize the review by highlighting the challenges and opportunities associated with studying membrane-membrane interactions and possible future research directions.
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Affiliation(s)
- Bineet Sharma
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; (B.S.); (H.M.)
| | - Hossein Moghimianavval
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; (B.S.); (H.M.)
| | - Sung-Won Hwang
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Allen P. Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; (B.S.); (H.M.)
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48105, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48105, USA
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12
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Cyclodextrins increase membrane tension and are universal activators of mechanosensitive channels. Proc Natl Acad Sci U S A 2021; 118:2104820118. [PMID: 34475213 DOI: 10.1073/pnas.2104820118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 07/29/2021] [Indexed: 11/18/2022] Open
Abstract
The bacterial mechanosensitive channel of small conductance (MscS) has been extensively studied to understand how mechanical forces are converted into the conformational changes that underlie mechanosensitive (MS) channel gating. We showed that lipid removal by β-cyclodextrin can mimic membrane tension. Here, we show that all cyclodextrins (CDs) can activate reconstituted Escherichia coli MscS, that MscS activation by CDs depends on CD-mediated lipid removal, and that the CD amount required to gate MscS scales with the channel's sensitivity to membrane tension. Importantly, cholesterol-loaded CDs do not activate MscS. CD-mediated lipid removal ultimately causes MscS desensitization, which we show is affected by the lipid environment. While many MS channels respond to membrane forces, generalized by the "force-from-lipids" principle, their different molecular architectures suggest that they use unique ways to convert mechanical forces into conformational changes. To test whether CDs can also be used to activate other MS channels, we chose to investigate the mechanosensitive channel of large conductance (MscL) and demonstrate that CDs can also activate this structurally unrelated channel. Since CDs can open the least tension-sensitive MS channel, MscL, they should be able to open any MS channel that responds to membrane tension. Thus, CDs emerge as a universal tool for the structural and functional characterization of unrelated MS channels.
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13
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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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14
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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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15
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Strutt R, Hindley JW, Gregg J, Booth PJ, Harling JD, Law RV, Friddin MS, Ces O. Activating mechanosensitive channels embedded in droplet interface bilayers using membrane asymmetry. Chem Sci 2021; 12:2138-2145. [PMID: 34163978 PMCID: PMC8179348 DOI: 10.1039/d0sc03889j] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/03/2020] [Indexed: 11/21/2022] Open
Abstract
Droplet microcompartments linked by lipid bilayers show great promise in the construction of synthetic minimal tissues. Central to controlling the flow of information in these systems are membrane proteins, which can gate in response to specific stimuli in order to control the molecular flux between membrane separated compartments. This has been demonstrated with droplet interface bilayers (DIBs) using several different membrane proteins combined with electrical, mechanical, and/or chemical activators. Here we report the activation of the bacterial mechanosensitive channel of large conductance (MscL) in a dioleoylphosphatidylcholine:dioleoylphosphatidylglycerol DIB by controlling membrane asymmetry. We show using electrical measurements that the incorporation of lysophosphatidylcholine (LPC) into one of the bilayer leaflets triggers MscL gating in a concentration-dependent manner, with partial and full activation observed at 10 and 15 mol% LPC respectively. Our findings could inspire the design of new minimal tissues where flux pathways are dynamically defined by lipid composition.
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Affiliation(s)
- Robert Strutt
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- Institute of Chemical Biology, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
| | - James W Hindley
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- Institute of Chemical Biology, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- FabriCELL, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
| | - Jordan Gregg
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
| | - Paula J Booth
- FabriCELL, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- Department of Chemistry, King's College London SE1 1DB London UK
| | - John D Harling
- Medicinal Chemistry, GSK Gunnels Wood Road, Stevenage SG1 2NY UK
| | - Robert V Law
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- Institute of Chemical Biology, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- FabriCELL, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
| | - Mark S Friddin
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- Dyson School of Design Engineering, Imperial College London Imperial College Road SW7 2AZ UK
| | - Oscar Ces
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- Institute of Chemical Biology, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
- FabriCELL, Imperial College London, Molecular Sciences Research Hub Shepherd's Bush London W12 0BZ UK
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16
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Haylock S, Friddin MS, Hindley JW, Rodriguez E, Charalambous K, Booth PJ, Barter LMC, Ces O. Membrane protein mediated bilayer communication in networks of droplet interface bilayers. Commun Chem 2020; 3:77. [PMID: 34113722 PMCID: PMC7610947 DOI: 10.1038/s42004-020-0322-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Droplet interface bilayers (DIBs) are model membranes formed between lipid monolayer-encased water droplets in oil. Compared to conventional methods, one of the most unique properties of DIBs is that they can be connected together to generate multi-layered ‘tissue-like’ networks, however introducing communication pathways between these compartments typically relies on water-soluble pores that are unable to gate. Here, we show that network connectivity can instead be achieved using a water-insoluble membrane protein by successfully reconstituting a chemically activatable mutant of the mechanosensitive channel MscL into a network of DIBs. Moreover, we also show how the small molecule activator can diffuse through an open channel and across the neighbouring droplet to activate MscL present in an adjacent bilayer. This demonstration of membrane protein mediated bilayer communication could prove key toward developing the next generation of responsive bilayer networks capable of defining information flow inside a minimal tissue.
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Affiliation(s)
- Stuart Haylock
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK.,Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK
| | - Mark S Friddin
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK
| | - James W Hindley
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK.,Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK.,fabriCELL, Imperial College London, 80 Wood Lane, London W12 0BZ, UK
| | - Enrique Rodriguez
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK
| | - Kalypso Charalambous
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK
| | - Paula J Booth
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London SE1 1DB, UK
| | - Laura M C Barter
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK.,Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK
| | - Oscar Ces
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK.,Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 80 Wood Lane, London W12 0BZ, UK.,fabriCELL, Imperial College London, 80 Wood Lane, London W12 0BZ, UK
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17
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Darley E, Singh JKD, Surace NA, Wickham SFJ, Baker MAB. The Fusion of Lipid and DNA Nanotechnology. Genes (Basel) 2019; 10:E1001. [PMID: 31816934 PMCID: PMC6947036 DOI: 10.3390/genes10121001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/18/2019] [Accepted: 11/26/2019] [Indexed: 01/06/2023] Open
Abstract
Lipid membranes form the boundary of many biological compartments, including organelles and cells. Consisting of two leaflets of amphipathic molecules, the bilayer membrane forms an impermeable barrier to ions and small molecules. Controlled transport of molecules across lipid membranes is a fundamental biological process that is facilitated by a diverse range of membrane proteins, including ion-channels and pores. However, biological membranes and their associated proteins are challenging to experimentally characterize. These challenges have motivated recent advances in nanotechnology towards building and manipulating synthetic lipid systems. Liposomes-aqueous droplets enclosed by a bilayer membrane-can be synthesised in vitro and used as a synthetic model for the cell membrane. In DNA nanotechnology, DNA is used as programmable building material for self-assembling biocompatible nanostructures. DNA nanostructures can be functionalised with hydrophobic chemical modifications, which bind to or bridge lipid membranes. Here, we review approaches that combine techniques from lipid and DNA nanotechnology to engineer the topography, permeability, and surface interactions of membranes, and to direct the fusion and formation of liposomes. These approaches have been used to study the properties of membrane proteins, to build biosensors, and as a pathway towards assembling synthetic multicellular systems.
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Affiliation(s)
- Es Darley
- School of Biotechnology and Biomolecular Science, UNSW Sydney, Kensington 2052, Australia;
| | - Jasleen Kaur Daljit Singh
- School of Chemistry, University of Sydney, Camperdown 2006, Australia; (J.K.D.S.); (N.A.S.)
- School of Chemical and Biomolecular Engineering, University of Sydney, Camperdown 2006, Australia
- Sydney Nanoscience Institute, University of Sydney, Camperdown 2006, Australia
| | - Natalie A. Surace
- School of Chemistry, University of Sydney, Camperdown 2006, Australia; (J.K.D.S.); (N.A.S.)
| | - Shelley F. J. Wickham
- School of Chemistry, University of Sydney, Camperdown 2006, Australia; (J.K.D.S.); (N.A.S.)
- Sydney Nanoscience Institute, University of Sydney, Camperdown 2006, Australia
- School of Physics, University of Sydney, Camperdown 2006, Australia
| | - Matthew A. B. Baker
- School of Biotechnology and Biomolecular Science, UNSW Sydney, Kensington 2052, Australia;
- CSIRO Synthetic Biology Future Science Platform, GPO Box 2583, Brisbane, QLD 4001, Australia
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18
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Jaggers OB, Ridone P, Martinac B, Baker MAB. Fluorescence microscopy of piezo1 in droplet hydrogel bilayers. Channels (Austin) 2019; 13:102-109. [PMID: 30885080 PMCID: PMC6527062 DOI: 10.1080/19336950.2019.1586046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Mechanosensitive ion channels are membrane gated pores which are activated by mechanical stimuli. The focus of this study is on Piezo1, a newly discovered, large, mammalian, mechanosensitive ion channel, which has been linked to diseases such as dehydrated hereditary stomatocytosis (Xerocytosis) and lymphatic dysplasia. Here we utilize an established in-vitro artificial bilayer system to interrogate single Piezo1 channel activity. The droplet-hydrogel bilayer (DHB) system uniquely allows the simultaneous recording of electrical activity and fluorescence imaging of labelled protein. We successfully reconstituted fluorescently labelled Piezo1 ion channels in DHBs and verified activity using electrophysiology in the same system. We demonstrate successful insertion and activation of hPiezo1-GFP in bilayers of varying composition. Furthermore, we compare the Piezo1 bilayer reconstitution with measurements of insertion and activation of KcsA channels to reproduce the channel conductances reported in the literature. Together, our results showcase the use of DHBs for future experiments allowing simultaneous measurements of ion channel gating while visualising the channel proteins using fluorescence.
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Affiliation(s)
- Oskar B Jaggers
- a School of Biotechnology and Biomolecular Science , UNSW , Kensington , Australia.,b Victor Chang Cardiac Research Institute , Darlinghurst , Australia
| | - Pietro Ridone
- b Victor Chang Cardiac Research Institute , Darlinghurst , Australia
| | - Boris Martinac
- b Victor Chang Cardiac Research Institute , Darlinghurst , Australia
| | - Matthew A B Baker
- a School of Biotechnology and Biomolecular Science , UNSW , Kensington , Australia
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19
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Murthy SE, Dubin AE, Whitwam T, Jojoa-Cruz S, Cahalan SM, Mousavi SAR, Ward AB, Patapoutian A. OSCA/TMEM63 are an Evolutionarily Conserved Family of Mechanically Activated Ion Channels. eLife 2018; 7:e41844. [PMID: 30382938 PMCID: PMC6235560 DOI: 10.7554/elife.41844] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 10/11/2018] [Indexed: 12/17/2022] Open
Abstract
Mechanically activated (MA) ion channels convert physical forces into electrical signals, and are essential for eukaryotic physiology. Despite their importance, few bona-fide MA channels have been described in plants and animals. Here, we show that various members of the OSCA and TMEM63 family of proteins from plants, flies, and mammals confer mechanosensitivity to naïve cells. We conclusively demonstrate that OSCA1.2, one of the Arabidopsis thaliana OSCA proteins, is an inherently mechanosensitive, pore-forming ion channel. Our results suggest that OSCA/TMEM63 proteins are the largest family of MA ion channels identified, and are conserved across eukaryotes. Our findings will enable studies to gain deep insight into molecular mechanisms of MA channel gating, and will facilitate a better understanding of mechanosensory processes in vivo across plants and animals.
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Affiliation(s)
- Swetha E Murthy
- Department of Neuroscience, Dorris Neuroscience CenterThe Scripps Research InstituteCaliforniaUnited States
| | - Adrienne E Dubin
- Department of Neuroscience, Dorris Neuroscience CenterThe Scripps Research InstituteCaliforniaUnited States
| | - Tess Whitwam
- Department of Neuroscience, Dorris Neuroscience CenterThe Scripps Research InstituteCaliforniaUnited States
| | - Sebastian Jojoa-Cruz
- Department of Integrative Structural and Computational BiologyThe Scripps Research Institute, Howard Hughes Medical InstituteCaliforniaUnited States
| | - Stuart M Cahalan
- Department of Neuroscience, Dorris Neuroscience CenterThe Scripps Research InstituteCaliforniaUnited States
| | - Seyed Ali Reza Mousavi
- Department of Neuroscience, Dorris Neuroscience CenterThe Scripps Research InstituteCaliforniaUnited States
| | - Andrew B Ward
- Department of Integrative Structural and Computational BiologyThe Scripps Research Institute, Howard Hughes Medical InstituteCaliforniaUnited States
| | - Ardem Patapoutian
- Department of Neuroscience, Dorris Neuroscience CenterThe Scripps Research InstituteCaliforniaUnited States
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20
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Nakayama Y, Hashimoto KI, Sawada Y, Sokabe M, Kawasaki H, Martinac B. Corynebacterium glutamicum mechanosensitive channels: towards unpuzzling "glutamate efflux" for amino acid production. Biophys Rev 2018; 10:1359-1369. [PMID: 30209745 PMCID: PMC6233337 DOI: 10.1007/s12551-018-0452-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022] Open
Abstract
Corynebacterium glutamicum has been utilized for industrial amino acid production, especially for monosodium glutamate (MSG), the food-additive for the "UMAMI" category of taste sensation, which is one of the five human basic tastes. Glutamate export from these cells is facilitated by the opening of mechanosensitive channels in the cell membrane within the bacterial cell envelope following specific treatments, such as biotin limitation, addition of Tween 40 or penicillin. A long-unsolved puzzle still remains how and why C. glutamicum mechanosensitive channels are activated by these treatments to export glutamate. Unlike mechanosensitive channels in other bacteria, these channels are not simply osmotic safety valves that prevent these bacteria from bursting upon a hypo-osmotic shock. They also function as metabolic valves to continuously release glutamate as components of a pump-and-leak mechanism regulating the cellular turgor pressure. Recent studies have demonstrated that the opening of the mechanosensitive channel, MscCG, mainly facilitates the efflux of glutamate and not of other amino acids and that the "force-from-lipids" gating mechanism of channels also applies to the MscCG channel. The bacterial types of mechanosensitive channels are found in cell-walled organisms from bacteria to land plants, where their physiological functions have been specialized beyond their basic function in bacterial osmoregulation. In the case of the C. glutamicum MscCG channels, they have evolved to function as specialized glutamate exporters.
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Affiliation(s)
- Yoshitaka Nakayama
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia.
| | - Ken-Ichi Hashimoto
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Yasuyuki Sawada
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Hisashi Kawasaki
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Boris Martinac
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, 2010, Australia
- St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW, 2010, Australia
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21
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Oiki S, Iwamoto M. Lipid Bilayers Manipulated through Monolayer Technologies for Studies of Channel-Membrane Interplay. Biol Pharm Bull 2018; 41:303-311. [PMID: 29491206 DOI: 10.1248/bpb.b17-00708] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fluidity and mosaicity are two critical features of biomembranes, by which membrane proteins function through chemical and physical interactions within a bilayer. To understand this complex and dynamic system, artificial lipid bilayer membranes have served as unprecedented tools for experimental examination, in which some aspects of biomembrane features have been extracted, and to which various methodologies have been applied. Among the lipid bilayers involving liposomes, planar lipid bilayers and nanodiscs, recent developments of lipid bilayer methods and the results of our channel studies are reviewed herein. Principles and techniques of bilayer formation are summarized, which have been extended to the current techniques, where a bilayer is formed from lipid-coated water-in-oil droplets (water-in-oil bilayer). In our newly developed method, termed the contact bubble bilayer (CBB) method, a water bubble is blown from a pipette into a bulk oil phase, and monolayer-lined bubbles are docked to form a bilayer through manipulation by pipette. An asymmetric bilayer can be readily formed, and changes in composition in one leaflet were possible. Taking advantage of the topological configuration of the CBB, such that the membrane's hydrophobic interior is contiguous with the surrounding bulk organic phase, oil-dissolved substances such as cholesterol were delivered directly to the bilayer interior to perfuse around the membrane-embedded channels (membrane perfusion), and current recordings in the single-channel allowed detection of immediate changes in the channels' response to cholesterol. Chemical and mechanical manipulation in each monolayer (monolayer technology) allows the examination of dynamic channel-membrane interplay.
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Affiliation(s)
- Shigetoshi Oiki
- Department of Molecular Physiology & Biophysics, University of Fukui Faculty of Medical Sciences
| | - Masayuki Iwamoto
- Department of Molecular Physiology & Biophysics, University of Fukui Faculty of Medical Sciences
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22
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Ye J, Tang S, Meng L, Li X, Wen X, Chen S, Niu L, Li X, Qiu W, Hu H, Jiang M, Shang S, Shu Q, Zheng H, Duan S, Li Y. Ultrasonic Control of Neural Activity through Activation of the Mechanosensitive Channel MscL. NANO LETTERS 2018; 18:4148-4155. [PMID: 29916253 DOI: 10.1021/acs.nanolett.8b00935] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Externally controlling the excitation of a neuronal subset through ion channels activation can modulate the firing pattern of an entire neural circuit in vivo. As nanovalves in the cell membrane, ion channels can be opened by light (optogenetics) or ultrasonic (sonogenetics) means. A thoroughly analyzed force sensor is the Escherichia coli mechano sensitive channel of large conductance (MscL). Here we expressed MscL in rat hippocampal neurons in a primary culture and showed that it could be activated by low-pressure ultrasound pulses. The gain-of-function mutation, I92L, sensitized MscL's sonic response, triggering action potentials at a peak negative pressure as low as 0.25 MPa. Further, the I92L MscL reliably elicited individual spikes by timed brief pulses, making excitation programmable. Because MscL opens to tension in the lipid bilayer, requiring no other proteins or ligands, it could be developed into a general noninvasive sonogenetic tool to manipulate the activities of neurons or other cells and potential nanodevices.
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Affiliation(s)
- Jia Ye
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Siyang Tang
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Long Meng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Key Laboratory for MRI , Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen , 518005 , China
| | - Xia Li
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Xiaoxu Wen
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Sihan Chen
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Lili Niu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Key Laboratory for MRI , Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen , 518005 , China
| | - Xiangyao Li
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Weibao Qiu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Key Laboratory for MRI , Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen , 518005 , China
| | - Hailan Hu
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Mizu Jiang
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Shiqiang Shang
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Qiang Shu
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Key Laboratory for MRI , Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences , Shenzhen , 518005 , China
| | - Shumin Duan
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
| | - Yuezhou Li
- Children's Hospital and Department of Biophysics, NHC and CAMS Key Laboratory of Medical Neurobiology , Zhejiang University School of Medicine , Hangzhou , Zhejiang 310058 , China
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23
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Challita EJ, Makhoul-Mansour MM, Freeman EC. Reconfiguring droplet interface bilayer networks through sacrificial membranes. BIOMICROFLUIDICS 2018; 12:034112. [PMID: 30867859 PMCID: PMC6404924 DOI: 10.1063/1.5023386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/22/2018] [Indexed: 05/19/2023]
Abstract
The droplet interface bilayer platform allows for the fabrication of stimuli-responsive microfluidic materials, using phospholipids as an organic surfactant in water-in-oil mixtures. In this approach, lipid-coated droplets are adhered together in arranged networks, forming lipid bilayer membranes with embedded transporters and establishing selective exchange pathways between neighboring aqueous subcompartments. The resulting material is a biologically inspired droplet-based material that exhibits emergent properties wherein different droplets accomplish different functions, similar to multicellular organisms. These networks have been successfully applied towards biomolecular sensing and energy harvesting applications. However, unlike their source of inspiration, these droplet structures are often static. This limitation not only renders the networks unable to adapt or modify their structure and function after formation but also limits their long term use as passive ionic exchange between neighboring droplet pairs may initiate immediately after the membranes are established. This work addresses this shortcoming by rupturing selected sacrificial membranes within the collections of droplets to rearrange the remaining droplets into new configurations, redirecting the droplet-droplet exchange pathways. This is accomplished through electrical shocks applied between selected droplets. Experimental outcomes are compared to predictions provided by a coupled mechanical-electrical model for the droplet networks, and then advanced configurations are proposed using this model.
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Affiliation(s)
- Elio J Challita
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, College of Engineering, University of Georgia, Athens, Georgia 30602, USA
| | - Michelle M Makhoul-Mansour
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, College of Engineering, University of Georgia, Athens, Georgia 30602, USA
| | - Eric C Freeman
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, College of Engineering, University of Georgia, Athens, Georgia 30602, USA
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24
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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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25
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Soloperto A, Boccaccio A, Contestabile A, Moroni M, Hallinan GI, Palazzolo G, Chad J, Deinhardt K, Carugo D, Difato F. Mechano-sensitization of mammalian neuronal networks through expression of the bacterial large-conductance mechanosensitive ion channel. J Cell Sci 2018; 131:jcs210393. [PMID: 29361543 PMCID: PMC5897719 DOI: 10.1242/jcs.210393] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/13/2018] [Indexed: 12/11/2022] Open
Abstract
Development of remote stimulation techniques for neuronal tissues represents a challenging goal. Among the potential methods, mechanical stimuli are the most promising vectors to convey information non-invasively into intact brain tissue. In this context, selective mechano-sensitization of neuronal circuits would pave the way to develop a new cell-type-specific stimulation approach. We report here, for the first time, the development and characterization of mechano-sensitized neuronal networks through the heterologous expression of an engineered bacterial large-conductance mechanosensitive ion channel (MscL). The neuronal functional expression of the MscL was validated through patch-clamp recordings upon application of calibrated suction pressures. Moreover, we verified the effective development of in-vitro neuronal networks expressing the engineered MscL in terms of cell survival, number of synaptic puncta and spontaneous network activity. The pure mechanosensitivity of the engineered MscL, with its wide genetic modification library, may represent a versatile tool to further develop a mechano-genetic approach.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Alessandro Soloperto
- Neuroscience and Brain Technologies Dept., Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Anna Boccaccio
- Institute of Biophysics, National Research Council of Italy, 16149 Genoa, Italy
| | - Andrea Contestabile
- Neuroscience and Brain Technologies Dept., Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Monica Moroni
- Center for Neuroscience and Cognitive Systems, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy
| | - Grace I Hallinan
- Biological Sciences and Institute for Life Sciences, University of Southampton, SO17 1BJ Southampton, UK
| | - Gemma Palazzolo
- Neuroscience and Brain Technologies Dept., Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - John Chad
- Biological Sciences and Institute for Life Sciences, University of Southampton, SO17 1BJ Southampton, UK
| | - Katrin Deinhardt
- Biological Sciences and Institute for Life Sciences, University of Southampton, SO17 1BJ Southampton, UK
| | - Dario Carugo
- Faculty of Engineering and the Environment, University of Southampton, SO17 1BJ Southampton, UK
| | - Francesco Difato
- Neuroscience and Brain Technologies Dept., Istituto Italiano di Tecnologia, 16163 Genoa, Italy
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Renauld S, Cortes S, Bersch B, Henry X, De Waard M, Schaack B. Functional reconstitution of cell-free synthesized purified Kv channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2373-2380. [DOI: 10.1016/j.bbamem.2017.09.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/29/2017] [Accepted: 09/05/2017] [Indexed: 12/11/2022]
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Beurg M, Fettiplace R. PIEZO2 as the anomalous mechanotransducer channel in auditory hair cells. J Physiol 2017; 595:7039-7048. [PMID: 28983916 PMCID: PMC5709317 DOI: 10.1113/jp274996] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/01/2017] [Indexed: 12/24/2022] Open
Abstract
Throughout postnatal maturation of the mouse inner ear, cochlear hair cells display at least two types of mechanically gated ion channel: normal mechanotransducer (MT) channels at the tips of the stereocilia, activated by tension in interciliary tip links, and anomalous mechanosensitive (MS) channels on the top surface of the cells. The anomalous MS channels are responsible for the reverse‐polarity current that appears in mutants in which normal transduction is lost. They are also seen in wild‐type hair cells around birth, appearing 2 days earlier than normal MT channels, and being down‐regulated with the emergence of the normal channels. We review the evidence that the normal and anomalous channels are distinct channel types, which includes differences in localization, susceptibility to pharmacological agents, single‐channel conductance and Ca2+ permeability. The dichotomy is reinforced by the observation that the anomalous current is absent in cochlear cells of Piezo2‐null mice, even though the normal MT current persists. The anomalous current is suppressed by high intracellular Ca2+, suggesting that influx of the divalent ion via more Ca2+‐permeable normal MT channels inhibits the anomalous channels, thus explaining the temporal relationship between the two. Piezo2‐null mice have largely normal hearing, exhibiting up to 20 dB elevation in threshold in the acoustic brainstem response, so raising questions about the significance of PIEZO2 in the cochlea. Since the anomalous current declines with postnatal age, PIEZO2 may contribute to hair cell development, but it does not underlie the normal MT current. Its role in the development of hearing is not understood.
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Affiliation(s)
- Maryline Beurg
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Robert Fettiplace
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
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de Bruin A, Friddin MS, Elani Y, Brooks NJ, Law R, Seddon JM, Ces O. A transparent 3D printed device for assembling droplet hydrogel bilayers (DHBs). RSC Adv 2017. [DOI: 10.1039/c7ra09406j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We report a new approach for assembling droplet hydrogel bilayers (DHBs) using a transparent 3D printed device.
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Affiliation(s)
| | - Mark S. Friddin
- Department of Chemistry
- Imperial College London
- London
- UK
- Institute of Chemical Biology
| | - Yuval Elani
- Department of Chemistry
- Imperial College London
- London
- UK
- Institute of Chemical Biology
| | - Nicholas J. Brooks
- Department of Chemistry
- Imperial College London
- London
- UK
- Institute of Chemical Biology
| | - Robert V. Law
- Department of Chemistry
- Imperial College London
- London
- UK
- Institute of Chemical Biology
| | - John M. Seddon
- Department of Chemistry
- Imperial College London
- London
- UK
- Institute of Chemical Biology
| | - Oscar Ces
- Department of Chemistry
- Imperial College London
- London
- UK
- Institute of Chemical Biology
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