1
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Salter LC, Wojciechowski JP, McLean B, Charchar P, Barnes PRF, Creamer A, Doutch J, Barriga HMG, Holme MN, Yarovsky I, Stevens MM. 3,4-Ethylenedioxythiophene Hydrogels: Relating Structure and Charge Transport in Supramolecular Gels. Chem Mater 2024; 36:3092-3106. [PMID: 38617802 PMCID: PMC11007859 DOI: 10.1021/acs.chemmater.3c01360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 03/05/2024] [Accepted: 03/05/2024] [Indexed: 04/16/2024]
Abstract
Ionic charge transport is a ubiquitous language of communication in biological systems. As such, bioengineering is in constant need of innovative, soft, and biocompatible materials that facilitate ionic conduction. Low molecular weight gelators (LMWGs) are complex self-assembled materials that have received increasing attention in recent years. Beyond their biocompatible, self-healing, and stimuli responsive facets, LMWGs can be viewed as a "solid" electrolyte solution. In this work, we investigate 3,4-ethylenedioxythiophene (EDOT) as a capping group for a small peptide library, which we use as a system to understand the relationship between modes of assembly and charge transport in supramolecular gels. Through a combination of techniques including small-angle neutron scattering (SANS), NMR-based Van't Hoff analysis, atomic force microscopy (AFM), rheology, four-point probe, and electrochemical impedance spectroscopy (EIS), we found that modifications to the peptide sequence result in distinct assembly pathways, thermodynamic parameters, mechanical properties, and ionic conductivities. Four-point probe conductivity measurements and electrochemical impedance spectroscopy suggest that ionic conductivity is approximately doubled by programmable gel assemblies with hollow cylinder morphologies relative to gels containing solid fibers or a control electrolyte. More broadly, it is hoped this work will serve as a platform for those working on charge transport of aqueous soft materials in general.
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Affiliation(s)
- Luke C.
B. Salter
- Department
of Materials and Department of Bioengineering, Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jonathan P. Wojciechowski
- Department
of Materials and Department of Bioengineering, Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Ben McLean
- School
of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- ARC
Research Hub for Australian Steel Innovation, https://www.rmit.edu.au/research/centres-collaborations/multi-partner-collaborations/arc-research-hub-aus-steel-manufacturing
| | - Patrick Charchar
- School
of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Piers R. F. Barnes
- Department
of Physics, Imperial College London, London SW7 2AZ, United
Kingdom
| | - Adam Creamer
- Department
of Materials and Department of Bioengineering, Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - James Doutch
- ISIS
Muon and Neutron Source, Rutherford Appleton
Laboratory, Harwell Campus, Oxfordshire OX11 0QX, United Kingdom
| | - Hanna M. G. Barriga
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Margaret N. Holme
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Irene Yarovsky
- School
of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Molly M. Stevens
- Department
of Materials and Department of Bioengineering, Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden
- Department
of Physiology, Anatomy and Genetics, Department of Engineering Science,
and Kavli Institute for Nanoscience Discovery, University of Oxford, OX1
3QU, Oxford, United Kingdom
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2
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Sych T, Schlegel J, Barriga HMG, Ojansivu M, Hanke L, Weber F, Beklem Bostancioglu R, Ezzat K, Stangl H, Plochberger B, Laurencikiene J, El Andaloussi S, Fürth D, Stevens MM, Sezgin E. High-throughput measurement of the content and properties of nano-sized bioparticles with single-particle profiler. Nat Biotechnol 2024; 42:587-590. [PMID: 37308687 PMCID: PMC11021190 DOI: 10.1038/s41587-023-01825-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 05/10/2023] [Indexed: 06/14/2023]
Abstract
We introduce a method, single-particle profiler, that provides single-particle information on the content and biophysical properties of thousands of particles in the size range 5-200 nm. We use our single-particle profiler to measure the messenger RNA encapsulation efficiency of lipid nanoparticles, the viral binding efficiencies of different nanobodies, and the biophysical heterogeneity of liposomes, lipoproteins, exosomes and viruses.
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Affiliation(s)
- Taras Sych
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Jan Schlegel
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
| | - Hanna M G Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Miina Ojansivu
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Leo Hanke
- Division of Infectious Diseases, Department of Medicine Solna and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Florian Weber
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden
- Department Medical Engineering, University of Applied Sciences Upper Austria, Linz, Austria
| | | | - Kariem Ezzat
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Herbert Stangl
- Medical University of Vienna, Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Vienna, Austria
| | - Birgit Plochberger
- Department Medical Engineering, University of Applied Sciences Upper Austria, Linz, Austria
- LBG Ludwig Boltzmann Institute for Traumatology, Nanoscopy, Vienna, Austria
| | - Jurga Laurencikiene
- Lipid Laboratory, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden
| | | | - Daniel Fürth
- Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Molly M Stevens
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, UK
| | - Erdinc Sezgin
- Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Solna, Sweden.
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3
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Saunders C, Foote JEJ, Wojciechowski JP, Cammack A, Pedersen SV, Doutch JJ, Barriga HMG, Holme MN, Penders J, Chami M, Najer A, Stevens MM. Revealing Population Heterogeneity in Vesicle-Based Nanomedicines Using Automated, Single Particle Raman Analysis. ACS Nano 2023; 17:11713-11728. [PMID: 37279338 PMCID: PMC10311594 DOI: 10.1021/acsnano.3c02452] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/30/2023] [Indexed: 06/08/2023]
Abstract
The intrinsic heterogeneity of many nanoformulations is currently challenging to characterize on both the single particle and population level. Therefore, there is great opportunity to develop advanced techniques to describe and understand nanomedicine heterogeneity, which will aid translation to the clinic by informing manufacturing quality control, characterization for regulatory bodies, and connecting nanoformulation properties to clinical outcomes to enable rational design. Here, we present an analytical technique to provide such information, while measuring the nanocarrier and cargo simultaneously with label-free, nondestructive single particle automated Raman trapping analysis (SPARTA). We first synthesized a library of model compounds covering a range of hydrophilicities and providing distinct Raman signals. These compounds were then loaded into model nanovesicles (polymersomes) that can load both hydrophobic and hydrophilic cargo into the membrane or core regions, respectively. Using our analytical framework, we characterized the heterogeneity of the population by correlating the signal per particle from the membrane and cargo. We found that core and membrane loading can be distinguished, and we detected subpopulations of highly loaded particles in certain cases. We then confirmed the suitability of our technique in liposomes, another nanovesicle class, including the commercial formulation Doxil. Our label-free analytical technique precisely determines cargo location alongside loading and release heterogeneity in nanomedicines, which could be instrumental for future quality control, regulatory body protocols, and development of structure-function relationships to bring more nanomedicines to the clinic.
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Affiliation(s)
- Catherine Saunders
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - James E. J. Foote
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jonathan P. Wojciechowski
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Ana Cammack
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Simon V. Pedersen
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - James J. Doutch
- ISIS
Neutron and Muon Source, Rutherford Appleton Laboratory, Science and Technology Facilities Council, Didcot OX11 ODE, United Kingdom
| | - Hanna M. G. Barriga
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Margaret N. Holme
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Jelle Penders
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Mohamed Chami
- BioEM
Lab, Biozentrum, University of Basel, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Adrian Najer
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Molly M. Stevens
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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4
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Øvrebø Ø, Ojansivu M, Kartasalo K, Barriga HMG, Ranefall P, Holme MN, Stevens MM. RegiSTORM: channel registration for multi-color stochastic optical reconstruction microscopy. BMC Bioinformatics 2023; 24:237. [PMID: 37277712 DOI: 10.1186/s12859-023-05320-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/04/2023] [Indexed: 06/07/2023] Open
Abstract
BACKGROUND Stochastic optical reconstruction microscopy (STORM), a super-resolution microscopy technique based on single-molecule localizations, has become popular to characterize sub-diffraction limit targets. However, due to lengthy image acquisition, STORM recordings are prone to sample drift. Existing cross-correlation or fiducial marker-based algorithms allow correcting the drift within each channel, but misalignment between channels remains due to interchannel drift accumulating during sequential channel acquisition. This is a major drawback in multi-color STORM, a technique of utmost importance for the characterization of various biological interactions. RESULTS We developed RegiSTORM, a software for reducing channel misalignment by accurately registering STORM channels utilizing fiducial markers in the sample. RegiSTORM identifies fiducials from the STORM localization data based on their non-blinking nature and uses them as landmarks for channel registration. We first demonstrated accurate registration on recordings of fiducials only, as evidenced by significantly reduced target registration error with all the tested channel combinations. Next, we validated the performance in a more practically relevant setup on cells multi-stained for tubulin. Finally, we showed that RegiSTORM successfully registers two-color STORM recordings of cargo-loaded lipid nanoparticles without fiducials, demonstrating the broader applicability of this software. CONCLUSIONS The developed RegiSTORM software was demonstrated to be able to accurately register multiple STORM channels and is freely available as open-source (MIT license) at https://github.com/oystein676/RegiSTORM.git and https://doi.org/10.5281/zenodo.5509861 (archived), and runs as a standalone executable (Windows) or via Python (Mac OS, Linux).
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Affiliation(s)
- Øystein Øvrebø
- Department of Materials, Imperial College London, London, SW7 2AZ, UK
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK
- Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Miina Ojansivu
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77, Stockholm, Sweden
| | - Kimmo Kartasalo
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 171 77, Stockholm, Sweden
| | - Hanna M G Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77, Stockholm, Sweden
| | - Petter Ranefall
- SciLifeLab BioImage Informatics Facility, and Department of Information Technology, Uppsala University, 751 05, Uppsala, Sweden
| | - Margaret N Holme
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77, Stockholm, Sweden
| | - Molly M Stevens
- Department of Materials, Imperial College London, London, SW7 2AZ, UK.
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK.
- Institute of Biomedical Engineering, Imperial College London, London, SW7 2AZ, UK.
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77, Stockholm, Sweden.
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5
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Najer A, Blight J, Ducker CB, Gasbarri M, Brown JC, Che J, Høgset H, Saunders C, Ojansivu M, Lu Z, Lin Y, Yeow J, Rifaie-Graham O, Potter M, Tonkin R, Penders J, Doutch JJ, Georgiadou A, Barriga HMG, Holme MN, Cunnington AJ, Bugeon L, Dallman MJ, Barclay WS, Stellacci F, Baum J, Stevens MM. Potent Virustatic Polymer-Lipid Nanomimics Block Viral Entry and Inhibit Malaria Parasites In Vivo. ACS Cent Sci 2022; 8:1238-1257. [PMID: 36188342 PMCID: PMC9092191 DOI: 10.1021/acscentsci.1c01368] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Infectious diseases continue to pose a substantial burden on global populations, requiring innovative broad-spectrum prophylactic and treatment alternatives. Here, we have designed modular synthetic polymer nanoparticles that mimic functional components of host cell membranes, yielding multivalent nanomimics that act by directly binding to varied pathogens. Nanomimic blood circulation time was prolonged by reformulating polymer-lipid hybrids. Femtomolar concentrations of the polymer nanomimics were sufficient to inhibit herpes simplex virus type 2 (HSV-2) entry into epithelial cells, while higher doses were needed against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Given their observed virustatic mode of action, the nanomimics were also tested with malaria parasite blood-stage merozoites, which lose their invasive capacity after a few minutes. Efficient inhibition of merozoite invasion of red blood cells was demonstrated both in vitro and in vivo using a preclinical rodent malaria model. We envision these nanomimics forming an adaptable platform for developing pathogen entry inhibitors and as immunomodulators, wherein nanomimic-inhibited pathogens can be secondarily targeted to sites of immune recognition.
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Affiliation(s)
- Adrian Najer
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
- Department
of Life Sciences, Imperial College London, London, SW7 2AZ, U.K.
| | - Joshua Blight
- Department
of Life Sciences, Imperial College London, London, SW7 2AZ, U.K.
| | | | - Matteo Gasbarri
- Institute
of Materials, Ecole Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jonathan C. Brown
- Department
of Infectious Disease, Imperial College
London, London, W2 1PG, U.K.
| | - Junyi Che
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Håkon Høgset
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Catherine Saunders
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Miina Ojansivu
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Zixuan Lu
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Yiyang Lin
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Jonathan Yeow
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Omar Rifaie-Graham
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Michael Potter
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Renée Tonkin
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - Jelle Penders
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | - James J. Doutch
- Rutherford
Appleton Laboratory, ISIS Neutron and Muon
Source, STFC, Didcot OX11 ODE, U.K.
| | - Athina Georgiadou
- Department
of Infectious Disease, Imperial College
London, London, W2 1PG, U.K.
| | - Hanna M. G. Barriga
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Margaret N. Holme
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | | | - Laurence Bugeon
- Department
of Life Sciences, Imperial College London, London, SW7 2AZ, U.K.
| | | | - Wendy S. Barclay
- Department
of Infectious Disease, Imperial College
London, London, W2 1PG, U.K.
| | - Francesco Stellacci
- Institute
of Materials, Ecole Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute
of Bioengineering, Ecole Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jake Baum
- Department
of Life Sciences, Imperial College London, London, SW7 2AZ, U.K.
| | - Molly M. Stevens
- Department
of Materials, Department of Bioengineering, and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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6
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Utterström J, Barriga HMG, Holme MN, Selegård R, Stevens MM, Aili D. Peptide-Folding Triggered Phase Separation and Lipid Membrane Destabilization in Cholesterol-Rich Lipid Vesicles. Bioconjug Chem 2022; 33:736-746. [PMID: 35362952 PMCID: PMC9026255 DOI: 10.1021/acs.bioconjchem.2c00115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Liposome-based drug
delivery systems are widely used to improve
drug pharmacokinetics but can suffer from slow and unspecific release
of encapsulated drugs. Membrane-active peptides, based on sequences
derived or inspired from antimicrobial peptides (AMPs), could offer
means to trigger and control the release. Cholesterol is used in most
liposomal drug delivery systems (DDS) to improve the stability of
the formulation, but the activity of AMPs on cholesterol-rich membranes
tends to be very low, complicating peptide-triggered release strategies.
Here, we show a de novo designed AMP-mimetic peptide that efficiently
triggers content release from cholesterol-containing lipid vesicles
when covalently conjugated to headgroup-functionalized lipids. Binding
to vesicles induces peptide folding and triggers a lipid phase separation,
which in the presence of cholesterol results in high local peptide
concentrations at the lipid bilayer surface and rapid content release.
We anticipate that these results will facilitate the development of
peptide-based strategies for controlling and triggering drug release
from liposomal drug delivery systems.
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Affiliation(s)
- Johanna Utterström
- Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology, SE-581 83 Linköping, Sweden
| | - Hanna M G Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Margaret N Holme
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Robert Selegård
- Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology, SE-581 83 Linköping, Sweden
| | - Molly M Stevens
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.,Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Daniel Aili
- Laboratory of Molecular Materials, Division of Biophysics and Bioengineering, Department of Physics, Chemistry and Biology, SE-581 83 Linköping, Sweden
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7
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Nele V, Holme MN, Rashid MH, Barriga HMG, Le TC, Thomas MR, Doutch JJ, Yarovsky I, Stevens MM. Design of Lipid-Based Nanocarriers via Cation Modulation of Ethanol-Interdigitated Lipid Membranes. Langmuir 2021; 37:11909-11921. [PMID: 34581180 DOI: 10.1021/acs.langmuir.1c02076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Short-chain alcohols (i.e., ethanol) can induce membrane interdigitation in saturated-chain phosphatidylcholines (PCs). In this process, alcohol molecules intercalate between phosphate heads, increasing lateral separation and favoring hydrophobic interactions between opposing acyl chains, which interpenetrate forming an interdigitated phase. Unraveling mechanisms underlying the interactions between ethanol and model lipid membranes has implications for cell biology, biochemistry, and for the formulation of lipid-based nanocarriers. However, investigations of ethanol-lipid membrane systems have been carried out in deionized water, which limits their applicability. Here, using a combination of small- and wide-angle X-ray scattering, small-angle neutron scattering, and all-atom molecular dynamics simulations, we analyzed the effect of varying CaCl2 and NaCl concentrations on ethanol-induced interdigitation. We observed that while ethanol addition leads to the interdigitation of bulk phase 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers in the presence of CaCl2 and NaCl regardless of the salt concentration, the ethanol-induced interdigitation of vesicular DPPC depends on the choice of cation and its concentration. These findings unravel a key role for cations in the ethanol-induced interdigitation of lipid membranes in either bulk phase or vesicular form.
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Affiliation(s)
- Valeria Nele
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
| | - Margaret N Holme
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - M Harunur Rashid
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- Department of Mathematics and Physics, North South University, Bashundhara, Dhaka 1229, Bangladesh
| | - Hanna M G Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Tu C Le
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Michael R Thomas
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
- London Centre for Nanotechnology and Department of Biochemical Engineering, University College London, 17-19 Gordon Street, London WC1H 0AH, U.K
| | - James J Doutch
- ISIS Neutron and Muon Source, STFC, Rutherford Appleton Laboratory, Didcot OX11 ODE, U.K
| | - Irene Yarovsky
- School of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Molly M Stevens
- Department of Materials, Department of Bioengineering and Institute of Biomedical Engineering, Imperial College London, London SW7 2AZ, U.K
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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8
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Abstract
Dispersions of nonlamellar lipid membrane assemblies are gaining increasing interest for drug delivery and protein therapeutic application. A key bottleneck has been the lack of rational design rules for these systems linking different lipid species and conditions to defined lattice parameters and structures. We have developed robust methods to form cubosomes (nanoparticles with porous internal structures) with water channel diameters of up to 171 Å, which are over 4 times larger than archetypal cubosome structures. The water channel diameter can be tuned via the incorporation of cholesterol and the charged lipid DOPA, DOPG, or DOPS. We have found that large molecules can be incorporated into the porous cubosome structure and that these molecules can interact with the internal cubosome membrane. This offers huge potential for accessible encapsulation and protection of biomolecules and development of confined interfacial reaction environments.
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Affiliation(s)
- Hanna M G Barriga
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub, White City Campus, Wood Lane , London W12 0BZ , U.K
| | - Oscar Ces
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub, White City Campus, Wood Lane , London W12 0BZ , U.K
| | - Robert V Law
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub, White City Campus, Wood Lane , London W12 0BZ , U.K
| | - John M Seddon
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub, White City Campus, Wood Lane , London W12 0BZ , U.K
| | - Nicholas J Brooks
- Department of Chemistry , Imperial College London , Molecular Sciences Research Hub, White City Campus, Wood Lane , London W12 0BZ , U.K
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9
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Barriga HMG, Holme MN, Stevens MM. Cubosomes: The Next Generation of Smart Lipid Nanoparticles? Angew Chem Int Ed Engl 2019; 58:2958-2978. [PMID: 29926520 PMCID: PMC6606436 DOI: 10.1002/anie.201804067] [Citation(s) in RCA: 237] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/12/2018] [Indexed: 12/13/2022]
Abstract
Cubosomes are highly stable nanoparticles formed from the lipid cubic phase and stabilized by a polymer based outer corona. Bicontinuous lipid cubic phases consist of a single lipid bilayer that forms a continuous periodic membrane lattice structure with pores formed by two interwoven water channels. Cubosome composition can be tuned to engineer pore sizes or include bioactive lipids, the polymer outer corona can be used for targeting and they are highly stable under physiological conditions. Compared to liposomes, the structure provides a significantly higher membrane surface area for loading of membrane proteins and small drug molecules. Owing to recent advances, they can be engineered in vitro in both bulk and nanoparticle formats with applications including drug delivery, membrane bioreactors, artificial cells, and biosensors. This review outlines recent advances in cubosome technology enabling their application and provides guidelines for the rational design of new systems for biomedical applications.
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Affiliation(s)
- Hanna M. G. Barriga
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Margaret N. Holme
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Molly M. Stevens
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
- Departments of Materials and Bioengineering and Institute of Biomedical Engineering, Imperial College London, London, UK
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Affiliation(s)
- Hanna M. G. Barriga
- Department of Medical Biochemistry and BiophysicsKarolinska Institute Stockholm Schweden
| | - Margaret N. Holme
- Department of Medical Biochemistry and BiophysicsKarolinska Institute Stockholm Schweden
| | - Molly M. Stevens
- Department of Medical Biochemistry and BiophysicsKarolinska Institute Stockholm Schweden
- Departments of Materials and Bioengineering and Institute of Biomedical EngineeringImperial College London London Großbritannien
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Holme M, Rana S, Barriga HMG, Kauscher U, Brooks NJ, Stevens MM. A Robust Liposomal Platform for Direct Colorimetric Detection of Sphingomyelinase Enzyme and Inhibitors. ACS Nano 2018; 12:8197-8207. [PMID: 30080036 PMCID: PMC6117748 DOI: 10.1021/acsnano.8b03308] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/20/2018] [Indexed: 05/23/2023]
Abstract
The enzyme sphingomyelinase (SMase) is an important biomarker for several diseases such as Niemann Pick's, atherosclerosis, multiple sclerosis, and HIV. We present a two-component colorimetric SMase activity assay that is more sensitive and much faster than currently available commercial assays. Herein, SMase-triggered release of cysteine from a sphingomyelin (SM)-based liposome formulation with 60 mol % cholesterol causes gold nanoparticle (AuNP) aggregation, enabling colorimetric detection of SMase activities as low as 0.02 mU/mL, corresponding to 1.4 pM concentration. While the lipid composition offers a stable, nonleaky liposome platform with minimal background signal, high specificity toward SMase avoids cross-reactivity of other similar phospholipases. Notably, use of an SM-based liposome formulation accurately mimics the natural in vivo substrate: the cell membrane. We studied the physical rearrangement process of the lipid membrane during SMase-mediated hydrolysis of SM to ceramide using small- and wide-angle X-ray scattering. A change in lipid phase from a liquid to gel state bilayer with increasing concentration of ceramide accounts for the observed increase in membrane permeability and consequent release of encapsulated cysteine. We further demonstrated the effectiveness of the sensor in colorimetric screening of small-molecule drug candidates, paving the way for the identification of novel SMase inhibitors in minutes. Taken together, the simplicity, speed, sensitivity, and naked-eye readout of this assay offer huge potential in point-of-care diagnostics and high-throughput drug screening.
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Affiliation(s)
- Margaret
N. Holme
- Department
of Materials, Imperial College London, London, SW7 2AZ, U.K.
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Subinoy Rana
- Department
of Materials, Imperial College London, London, SW7 2AZ, U.K.
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
- School
of Engineering, Newcastle University, Newcastle upon Tyne, NE1
7RU, U.K.
| | - Hanna M. G. Barriga
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Ulrike Kauscher
- Department
of Materials, Imperial College London, London, SW7 2AZ, U.K.
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
| | | | - Molly M. Stevens
- Department
of Materials, Imperial College London, London, SW7 2AZ, U.K.
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London, SW7 2AZ, U.K.
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Holme M, Rashid MH, Thomas MR, Barriga HMG, Herpoldt K, Heenan RK, Dreiss CA, Bañuelos JL, Xie HN, Yarovsky I, Stevens MM. Fate of Liposomes in the Presence of Phospholipase C and D: From Atomic to Supramolecular Lipid Arrangement. ACS Cent Sci 2018; 4:1023-1030. [PMID: 30159399 PMCID: PMC6107861 DOI: 10.1021/acscentsci.8b00286] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Indexed: 05/04/2023]
Abstract
Understanding the origins of lipid membrane bilayer rearrangement in response to external stimuli is an essential component of cell biology and the bottom-up design of liposomes for biomedical applications. The enzymes phospholipase C and D (PLC and PLD) both cleave the phosphorus-oxygen bonds of phosphate esters in phosphatidylcholine (PC) lipids. The atomic position of this hydrolysis reaction has huge implications for the stability of PC-containing self-assembled structures, such as the cell wall and lipid-based vesicle drug delivery vectors. While PLC converts PC to diacylglycerol (DAG), the interaction of PC with PLD produces phosphatidic acid (PA). Here we present a combination of small-angle scattering data and all-atom molecular dynamics simulations, providing insights into the effects of atomic-scale reorganization on the supramolecular assembly of PC membrane bilayers upon enzyme-mediated incorporation of DAG or PA. We observed that PC liposomes completely disintegrate in the presence of PLC, as conversion of PC to DAG progresses. At lower concentrations, DAG molecules within fluid PC bilayers form hydrogen bonds with backbone carbonyl oxygens in neighboring PC molecules and burrow into the hydrophobic region. This leads initially to membrane thinning followed by a swelling of the lamellar phase with increased DAG. At higher DAG concentrations, localized membrane tension causes a change in lipid phase from lamellar to the hexagonal and micellar cubic phases. Molecular dynamics simulations show that this destabilization is also caused in part by the decreased ability of DAG-containing PC membranes to coordinate sodium ions. Conversely, PLD-treated PC liposomes remain stable up to extremely high conversions to PA. Here, the negatively charged PA headgroup attracts significant amounts of sodium ions from the bulk solution to the membrane surface, leading to a swelling of the coordinated water layer. These findings are a vital step toward a fundamental understanding of the degradation behavior of PC lipid membranes in the presence of these clinically relevant enzymes, and toward the rational design of diagnostic and drug delivery technologies for phospholipase-dysregulation-based diseases.
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Affiliation(s)
- Margaret
N. Holme
- Department
of Materials, Imperial College London, London SW7 2AZ, United Kingdom
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - M. Harunur Rashid
- School
of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
| | - Michael R. Thomas
- Department
of Materials, Imperial College London, London SW7 2AZ, United Kingdom
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Hanna M. G. Barriga
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Karla−Luise Herpoldt
- Department
of Materials, Imperial College London, London SW7 2AZ, United Kingdom
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Richard K. Heenan
- STFC ISIS
Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
| | - Cécile A. Dreiss
- School
of Cancer and Pharmaceutical Sciences, King’s
College London, London SE1 9NH, United Kingdom
| | - José Leobardo Bañuelos
- STFC ISIS
Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom
- Department
of Physics, The University of Texas at El
Paso, El Paso, Texas 79968, United States
| | - Hai-nan Xie
- Department
of Materials, Imperial College London, London SW7 2AZ, United Kingdom
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Irene Yarovsky
- School
of Engineering, RMIT University, Melbourne, Victoria 3001, Australia
- E-mail:
| | - Molly M. Stevens
- Department
of Materials, Imperial College London, London SW7 2AZ, United Kingdom
- Department of Bioengineering and Institute of Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
- Department
of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
- E-mail:
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Gonzalez MA, Barriga HMG, Richens JL, Law RV, O'Shea P, Bresme F. How does ytterbium chloride interact with DMPC bilayers? A computational and experimental study. Phys Chem Chem Phys 2017; 19:9199-9209. [DOI: 10.1039/c7cp01400g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Lanthanide salts have been studied for many years, primarily in Nuclear Magnetic Resonance (NMR) experiments of mixed lipid–protein systems and more recently to study lipid flip-flop in model membrane systems.
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Affiliation(s)
| | | | | | - Robert V. Law
- Department of Chemistry
- Imperial College London
- London
- UK
| | - Paul O'Shea
- Department of Chemistry
- Imperial College London
- London
- UK
- School of Life Sciences
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Tyler AII, Barriga HMG, Parsons ES, McCarthy NLC, Ces O, Law RV, Seddon JM, Brooks NJ. Electrostatic swelling of bicontinuous cubic lipid phases. Soft Matter 2015; 11:3279-86. [PMID: 25790335 DOI: 10.1039/c5sm00311c] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Lipid bicontinuous cubic phases have attracted enormous interest as bio-compatible scaffolds for use in a wide range of applications including membrane protein crystallisation, drug delivery and biosensing. One of the major bottlenecks that has hindered exploitation of these structures is an inability to create targeted highly swollen bicontinuous cubic structures with large and tunable pore sizes. In contrast, cubic structures found in vivo have periodicities approaching the micron scale. We have been able to engineer and control highly swollen bicontinuous cubic phases of spacegroup Im3m containing only lipids by (a) increasing the bilayer stiffness by adding cholesterol and (b) inducing electrostatic repulsion across the water channels by addition of anionic lipids to monoolein. By controlling the composition of the ternary mixtures we have been able to achieve lattice parameters up to 470 Å, which is 5 times that observed in pure monoolein and nearly twice the size of any lipidic cubic phase reported previously. These lattice parameters significantly exceed the predicted maximum swelling for bicontinuous cubic lipid structures, which suggest that thermal fluctuations should destroy such phases for lattice parameters larger than 300 Å.
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Affiliation(s)
- Arwen I I Tyler
- Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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Barriga HMG, Parsons ES, McCarthy NLC, Ces O, Seddon JM, Law RV, Brooks NJ. Pressure-temperature phase behavior of mixtures of natural sphingomyelin and ceramide extracts. Langmuir 2015; 31:3678-3686. [PMID: 25742392 DOI: 10.1021/la504935c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ceramides are a group of sphingolipids that act as highly important signaling molecules in a variety of cellular processes including differentiation and apoptosis. The predominant in vivo synthetic pathway for ceramide formation is via sphingomyelinase catalyzed hydrolysis of sphingomyelin. The biochemistry of this essential pathway has been studied in detail; however, there is currently a lack of information on the structural behavior of sphingomyelin- and ceramide-rich model membrane systems, which is essential for developing a bottom-up understanding of ceramide signaling and platform formation. We have studied the lyotropic phase behavior of sphingomyelin-ceramide mixtures in excess water as a function of temperature (30-70 °C) and pressure (1-200 MPa) by small- and wide-angle X-ray scattering. At low ceramide concentrations the mixtures form the ripple gel phase (P(β)') below the gel transition temperature for sphingomyelin, and this observation has been confirmed by atomic force microscopy. Formation of the ripple gel phase can also be induced at higher temperatures via the application of hydrostatic pressure. At high ceramide concentration an inverse hexagonal phase (HII) is formed coexisting with a cubic phase.
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Affiliation(s)
- Hanna M G Barriga
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
| | - Edward S Parsons
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
| | - Nicola L C McCarthy
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
| | - Oscar Ces
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
| | - John M Seddon
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
| | - Robert V Law
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
| | - Nicholas J Brooks
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, United Kingdom
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Barriga HMG, Bazin R, Templer RH, Law RV, Ces O. Buffer-induced swelling and vesicle budding in binary lipid mixtures of dioleoylphosphatidylcholine:dioleoylphosphatidylethanolamine and dioleoylphosphatidylcholine:lysophosphatidylcholine using small-angle X-ray scattering and ³¹P static NMR. Langmuir 2015; 31:2979-2987. [PMID: 25738977 DOI: 10.1021/la5047996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A large variety of data exists on lipid phase behavior; however, it is mostly in nonbuffered systems over nonbiological temperature ranges. We present biophysical data on lipid mixtures of dioleoylphosphatidylcholine (DOPC), dioleoylphosphatidylethanolamine (DOPE), and lysophosphatidylcholine (LysoPC) examining their behaviors in excess water and buffer systems over the temperature range 4-34 °C. These mixtures are commonly used to investigate the effects of spontaneous curvature on integral membrane proteins. Using small-angle X-ray scattering (SAXS) and (31)P NMR, we observed lamellar and vesicle phases, with the buffer causing an increase in the layer spacing. Increasing amounts of DOPE in a DOPC bilayer decreased the layer spacing of the mesophase, while the opposite trend was observed for increasing amounts of LysoPC. (31)P static NMR was used to analyze the DOPC:LysoPC samples to investigate the vesicle sizes present, with evidence of vesicle budding observed at LysoPC concentrations above 30 mol %. NMR line shapes were fitted using an adapted program accounting for the distortion of the lipids within the magnetic field. The distortion of the vesicle, because of magnetic susceptibility, varied with LysoPC content, and a discontinuity was found in both the water and buffer samples. Generally, the distortion increased with LysoPC content; however, at a ratio of DOPC:LysoPC 60:40, the sample showed a level of distortion of the vesicle similar to that of pure DOPC. This implies an increased flexibility in the membrane at this point. Commonly, the assumption is that for increasing LysoPC concentration there is a reduction in membrane tension, implying that estimations of membrane tension based on spontaneous curvature assumptions may not be accurate.
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Affiliation(s)
- Hanna M G Barriga
- †Department of Chemistry, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Richard Bazin
- ‡Pfizer Global Research and Development, Sandwich, Kent CT13 9NJ, United Kingdom
| | - Richard H Templer
- †Department of Chemistry, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Robert V Law
- †Department of Chemistry, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Oscar Ces
- †Department of Chemistry, Imperial College London, London, SW7 2AZ, United Kingdom
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Barriga HMG, Booth P, Haylock S, Bazin R, Templer RH, Ces O. Droplet interface bilayer reconstitution and activity measurement of the mechanosensitive channel of large conductance from Escherichia coli. J R Soc Interface 2015; 11:20140404. [PMID: 25008079 PMCID: PMC4233688 DOI: 10.1098/rsif.2014.0404] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Droplet interface bilayers (DIBs) provide an exciting new platform for the study of membrane proteins in stable bilayers of controlled composition. To date, the successful reconstitution and activity measurement of membrane proteins in DIBs has relied on the use of the synthetic lipid 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC). We report the functional reconstitution of the mechanosensitive channel of large conductance (MscL) into DIBs composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), a lipid of significantly greater biological relevance than DPhPC. MscL functionality has been demonstrated using a fluorescence-based assay, showing that dye flow occurs across the DIB when MscL is gated by the cysteine reactive chemical 2-(trimethylammonium)ethyl methane thiosulfonate bromide (MTSET). MscL has already been the subject of a number of studies investigating its interaction with the membrane. We propose that this method will pave the way for future MscL studies looking in detail at the effects of controlled composition or membrane asymmetry on MscL activity using biologically relevant lipids and will also be applicable to other lipid–protein systems, paving the way for the study of membrane proteins in DIBs with biologically relevant lipids.
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Affiliation(s)
- Hanna M G Barriga
- Membrane Biophysics Platform, Institute of Chemical Biology and Department of Chemistry, Imperial College London, South Kensington, London SW7 2AX, UK
| | - Paula Booth
- Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Stuart Haylock
- Membrane Biophysics Platform, Institute of Chemical Biology and Department of Chemistry, Imperial College London, South Kensington, London SW7 2AX, UK
| | - Richard Bazin
- Pfizer Global Research and Development, Sandwich CT13 9NJ, UK
| | - Richard H Templer
- Membrane Biophysics Platform, Institute of Chemical Biology and Department of Chemistry, Imperial College London, South Kensington, London SW7 2AX, UK
| | - Oscar Ces
- Membrane Biophysics Platform, Institute of Chemical Biology and Department of Chemistry, Imperial College London, South Kensington, London SW7 2AX, UK
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Barriga HMG, Tyler AII, McCarthy NLC, Parsons ES, Ces O, Law RV, Seddon JM, Brooks NJ. Temperature and pressure tuneable swollen bicontinuous cubic phases approaching nature's length scales. Soft Matter 2015; 11:600-607. [PMID: 25430049 DOI: 10.1039/c4sm02343a] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Bicontinuous cubic structures offer enormous potential in applications ranging from protein crystallisation to drug delivery systems and have been observed in cellular membrane structures. One of the current bottlenecks in understanding and exploiting these structures is that cubic scaffolds produced in vitro are considerably smaller in size than those observed in biological systems, differing by almost an order of magnitude in some cases. We have addressed this technological bottleneck and developed a methodology capable of manufacturing highly swollen bicontinuous cubic membranes with length scales approaching those seen in vivo. Crucially, these cubic systems do not require the presence of proteins. We have generated highly swollen Im3m symmetry bicontinuous cubic phases with lattice parameters of up to 480 Å, composed of ternary mixtures of monoolein, cholesterol and negatively charged lipid (DOPS or DOPG) and we have been able to tune their lattice parameters. The swollen cubic phases are highly sensitive to both temperature and pressure; these structural changes are likely to be controlled by a fine balance between lipid headgroup repulsions and lateral pressure in the hydrocarbon chain region.
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Affiliation(s)
- H M G Barriga
- Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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