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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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Govey-Scotland J, Johnstone L, Myant C, Friddin MS. Towards skin-on-a-chip for screening the dermal absorption of cosmetics. LAB ON A CHIP 2023; 23:5068-5080. [PMID: 37938128 DOI: 10.1039/d3lc00691c] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Over the past few decades, there have been increasing global efforts to limit or ban the use of animals for testing cosmetic products. This ambition has been at the heart of international endeavours to develop new in vitro and animal-free approaches for assessing the safety of cosmetics. While several of these new approach methodologies (NAMs) have been approved for assessing different toxicological endpoints in the UK and across the EU, there remains an absence of animal-free methods for screening for dermal absorption; a measure that assesses the degree to which chemical substances can become systemically available through contact with human skin. Here, we identify some of the major technical barriers that have impacted regulatory recognition of an in vitro skin model for this purpose and propose how these could be overcome on-chip using artificial cells engineered from the bottom-up. As part of our future perspective, we suggest how this could be realised using a digital biomanufacturing pipeline that connects the design, microfluidic generation and 3D printing of artificial cells into user-crafted synthetic tissues. We highlight milestone achievements towards this goal, identify future challenges, and suggest how the ability to engineer animal-free skin models could have significant long-term consequences for dermal absorption screening, as well as for other applications.
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Affiliation(s)
- Jessica Govey-Scotland
- Dyson School of Design Engineering, Imperial College London, Exhibition Road, South Kensington, SW7 2AZ, London, UK.
- Institute for Molecular Sciences and Engineering, Imperial College London, Exhibition Road, South Kensington, SW7 2AZ, London, UK
| | - Liam Johnstone
- Office for Product Safety and Standards, 1 Victoria Street, SW1H 0ET, London, UK
| | - Connor Myant
- Dyson School of Design Engineering, Imperial College London, Exhibition Road, South Kensington, SW7 2AZ, London, UK.
| | - Mark S Friddin
- Dyson School of Design Engineering, Imperial College London, Exhibition Road, South Kensington, SW7 2AZ, London, UK.
- Institute for Molecular Sciences and Engineering, Imperial College London, Exhibition Road, South Kensington, SW7 2AZ, London, UK
- fabriCELL, Imperial College London and Kings College London, London, UK
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El-Beyrouthy J, Makhoul-Mansour M, Gulle J, Freeman E. Morphogenesis-inspired two-dimensional electrowetting in droplet networks. BIOINSPIRATION & BIOMIMETICS 2023; 18. [PMID: 37074106 DOI: 10.1088/1748-3190/acc779] [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: 10/21/2022] [Accepted: 03/24/2023] [Indexed: 05/03/2023]
Abstract
Living tissues dynamically reshape their internal cellular structures through carefully regulated cell-to-cell interactions during morphogenesis. These cellular rearrangement events, such as cell sorting and mutual tissue spreading, have been explained using the differential adhesion hypothesis, which describes the sorting of cells through their adhesive interactions with their neighbors. In this manuscript we explore a simplified form of differential adhesion within a bioinspired lipid-stabilized emulsion approximating cellular tissues. The artificial cellular tissues are created as a collection of aqueous droplets adhered together in a network of lipid membranes. Since this abstraction of the tissue does not retain the ability to locally vary the adhesion of the interfaces through biological mechanisms, instead we employ electrowetting with offsets generated by spatial variations in lipid compositions to capture a simple form of bioelectric control over the tissue characteristics. This is accomplished by first conducting experiments on electrowetting in droplet networks, next creating a model for describing electrowetting in collections of adhered droplets, then validating the model against the experimental measurements. This work demonstrates how the distribution of voltage within a droplet network may be tuned through lipid composition then used to shape directional contraction of the adhered structure using two-dimensional electrowetting events. Predictions from this model were used to explore the governing mechanics for complex electrowetting events in networks, including directional contraction and the formation of new interfaces.
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Affiliation(s)
- Joyce El-Beyrouthy
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
| | - Michelle Makhoul-Mansour
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
- College of Engineering, University of Tennessee Knoxville, Knoxville, TN, United States of America
| | - Jesse Gulle
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
| | - Eric Freeman
- School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, GA, United States of America
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Challenges and opportunities in achieving the full potential of droplet interface bilayers. Nat Chem 2022; 14:862-870. [PMID: 35879442 DOI: 10.1038/s41557-022-00989-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/27/2022] [Indexed: 12/27/2022]
Abstract
Model membranes can be used to elucidate the intricacies of the chemical processes that occur in cell membranes, but the perfectly biomimetic, yet bespoke, model membrane has yet to be built. Droplet interface bilayers are a new type of model membrane able to mimic some features of real cell membranes better than traditional models, such as liposomes and black lipid membranes. In this Perspective, we discuss recent work in the field that is starting to showcase the potential of these model membranes to enable the quantification of membrane processes, such as the behaviour of protein transporters and the prediction of in vivo drug movement, and their use as scaffolds for electrophysiological measurements. We also highlight the challenges that remain to enable droplet interface bilayers to achieve their full potential as artificial cells, and as biological analytical platforms to quantify molecular transport.
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PEG-in-PDMS drops stabilised by soft silicone skins as a model system for elastocapillary emulsions with explicit morphology control. J Colloid Interface Sci 2022; 628:1044-1057. [DOI: 10.1016/j.jcis.2022.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 11/19/2022]
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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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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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Allen ME, Albon J, Elani Y. Layer-by-layer assembly of multi-layered droplet interface bilayers (multi-DIBs). Chem Commun (Camb) 2021; 58:60-63. [PMID: 34877578 DOI: 10.1039/d1cc05155e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Droplet interface bilayers (DIBs) have tremendous promise as platforms for fundamental biomembrane studies and in biotechnology. Being composed of a single bilayer however limits their biomimetic potential, as many cell membrane motifs are composed of multiple aligned bilayers. We describe a technology to manufacture cell-sized multi-layered DIBs (multi-DIBs) by coating giant unilamellar vesicles with a further monolayer, and allowing such structures to make contact with themselves or a monolayer coated droplet. This easily customisable strategy will pave the way for an expanded repertoire of DIB functionality, for example by facilitating the incorporation of multiple-bilayer spanning protein complexes.
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Affiliation(s)
- Matthew E Allen
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub White City, London, W12 0BZ, UK.,Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London, W12 0BZ, UK. .,Department of Chemical Engineering, Imperial College London South Kensington, London, SW7 2AZ, UK
| | - James Albon
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub White City, London, W12 0BZ, UK
| | - Yuval Elani
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, 82 Wood Lane, London, W12 0BZ, UK. .,Department of Chemical Engineering, Imperial College London South Kensington, London, SW7 2AZ, UK
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El-Beyrouthy J, Freeman E. Characterizing the Structure and Interactions of Model Lipid Membranes Using Electrophysiology. MEMBRANES 2021; 11:319. [PMID: 33925756 PMCID: PMC8145864 DOI: 10.3390/membranes11050319] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/22/2021] [Accepted: 04/25/2021] [Indexed: 11/16/2022]
Abstract
The cell membrane is a protective barrier whose configuration determines the exchange both between intracellular and extracellular regions and within the cell itself. Consequently, characterizing membrane properties and interactions is essential for advancements in topics such as limiting nanoparticle cytotoxicity. Characterization is often accomplished by recreating model membranes that approximate the structure of cellular membranes in a controlled environment, formed using self-assembly principles. The selected method for membrane creation influences the properties of the membrane assembly, including their response to electric fields used for characterizing transmembrane exchanges. When these self-assembled model membranes are combined with electrophysiology, it is possible to exploit their non-physiological mechanics to enable additional measurements of membrane interactions and phenomena. This review describes several common model membranes including liposomes, pore-spanning membranes, solid supported membranes, and emulsion-based membranes, emphasizing their varying structure due to the selected mode of production. Next, electrophysiology techniques that exploit these structures are discussed, including conductance measurements, electrowetting and electrocompression analysis, and electroimpedance spectroscopy. The focus of this review is linking each membrane assembly technique to the properties of the resulting membrane, discussing how these properties enable alternative electrophysiological approaches to measuring membrane characteristics and interactions.
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Affiliation(s)
| | - Eric Freeman
- School of Environmental, Civil, Agricultural and Mechanical Engineering, College of Engineering, University of Georgia, Athens, GA 30602, USA;
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