Publications
220 results found
Elani Y, Purushothaman S, Booth PJ, et al., 2015, Measurements of the effect of membrane asymmetry on the mechanical properties of lipid bilayers, CHEMICAL COMMUNICATIONS, Vol: 51, Pages: 6976-6979, ISSN: 1359-7345
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- Citations: 76
Tyler AII, Clarke JA, Seddon JM, et al., 2015, Solid State NMR of Lipid Model Membranes, METHODS IN MEMBRANE LIPIDS, SECOND EDITION, Vol: 1232, Pages: 227-253, ISSN: 1064-3745
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- Citations: 7
Karamdad K, Law RV, Seddon JM, et al., 2014, Preparation and mechanical characterisation of giant unilamellar vesicles by a microfluidic method, Lab on a Chip, Vol: 15, Pages: 557-562, ISSN: 1473-0197
Giant unilamellar vesicles (GUVs) have a wide range of applications in biology and synthetic biology. As a result, new approaches for constructing GUVs using microfluidic techniques are emerging but there are still significant shortcomings in the control of fundamental vesicle structural parameters such as size, lamellarity, membrane composition and internal contents. We have developed a novel microfluidic platform to generate compositionally-controlled GUVs. Water-in-oil (W/O) droplets formed in a lipid-containing oil flow are transferred across an oil- water interface, facilitating the self-assembly of a phospholipid bilayer. In addition, for the first time we have studied the mechanical properties of the resultant lipid bilayers of the microfluidic GUVs. Using fluctuation analysis we were able to calculate the values for bending rigidity of giant vesicles assembled on chip and demonstrate that these correlate strongly with those of traditional low throughput strategies such as electroformation.
Brooks NJ, Seddon JM, 2014, High Pressure X-ray Studies of Lipid Membranes and Lipid Phase Transitions, Zeitschrift für Physikalische Chemie, Vol: 228, Pages: 987-1004, ISSN: 0942-9352
Hydrostatic pressure has dramatic effects on biomembrane structure and stability and is a key thermodynamic parameter in the context of the biology of deep sea organisms. Furthermore, high-pressure and pressure-jump studies are very useful tools in biophysics and biotechnology, where they can be used to study the mechanism and kinetics of lipid phase transitions, biomolecular transforma- tions, and protein folding/unfolding. Here, we first give an overview of the tech- nology currently available for X-ray scattering studies of soft matter systems under pressure. We then illustrate the use of this technology to study a variety of lipid membrane systems.
Carreras P, Elani Y, Law R, et al., 2014, A droplet trapping microfluidic device for the study of mass-transport across droplet interface bilayers, MicroTAS 2014
Carreras P, Law RV, Brooks NJ, et al., 2014, Microfluidic generation of droplet interface bilayer networks incorporating real-time size sorting in linear and non-linear configurations, Biomicrofluidics, Vol: 8, ISSN: 1932-1058
In this study, a novel droplet based microfluidic method for the generation of different sized droplet interface bilayers is reported. A microfluidic platform was designed, which allows the generation and packing of picoliter lipid coated water droplets. Droplets were generated by hydrodynamic focusing coupled with selective transport along grooves according to their size. A trapping structure at the end of the groove and a fine control of the flow pressures allowed for the droplets to be successfully trapped and aligned on demand. This technology facilitates the fine control of droplet size production as well as the generation of extended networks from a variety of lipids including 1,2-diphytanoyl-sn-glycero-3- phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine in linear and non- linear configurations, which is vital to the application of Droplet Interface Bilayers to biological network construction on-chip.
Sennoga CA, Seddon JM, Frueh JA, et al., 2014, DYNAMICS OF TARGETED MICROBUBBLE ADHESION UNDER PULSATILE COMPARED WITH STEADY FLOW, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 40, Pages: 2445-2457, ISSN: 0301-5629
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- Citations: 1
Ces O, Seddon J, Law R, et al., 2014, Novel Insights into the Mechanistic Routes of Lyotropic Phase Transitions, Publisher: INT UNION CRYSTALLOGRAPHY, Pages: C1187-C1187, ISSN: 2053-2733
Hamid HAA, Hashim R, Seddon JM, et al., 2014, Lyotropic phase behaviour and structural parameters of monosaccharide and disaccharide guerbet branched-chain β-D-glycosides, Advanced Materials Research, Vol: 895, Pages: 111-115, ISSN: 1022-6680
The phase behaviour and self-assembly structural parameters of a pair of monosaccharide and disaccharide Guerbet branched-chain β-D-glycosides, namely 2-octyldodecyl β-D-glucoside (β-Glc- C12C8) and 2-octyldodecyl β-D-maltoside (β-Mal- C12C8), have been studied by means of optical polarizing microscopy (OPM) and small-angle X-ray diffraction at room temperature (25°C). These compounds are sugar-based glycolipid surfactants having a total chain length of C20, and differ based on the increasing number of hydroxyl groups of the sugar headgroup (glucose and maltose). The repeat spacings obtained by X-ray diffraction as a function of water content have been used to determine the limiting hydration for the two glycosides. At room temperature, β-Glc-12C8 and β- Mal- C12C8 have limiting hydrations of 22 wt% and 25 wt%, corresponding to 8 - 10 and 10 - 12 water molecules per glycoside, respectively. At all water contents between 5 and 29 wt % water, these compounds adopt inverse hexagonal (HII) or fluid lamellar (Lα) phases. The structural parameters of these phases have been determined from the diffraction data, from the X-ray repeat spacings, densities and concentration of the glycosides. © (2014) Trans Tech Publications, Switzerland.
Conn CE, Seddon JM, 2014, Nonlamellar Lipid Aggregates, Liposomes, Lipid Bilayers and Model Membranes: From Basic Research to Application, Pages: 31-47, ISBN: 9781466507111
Amphiphilic molecules such as phospholipids, glycolipids, and monoacylglycerols (Figure 2.1) can spontaneously self-assemble into a wide range of ordered lyotropic liquid-crystalline mesophases (Shearman et al., 2006, 2010). The structural ordering within such phases can extend from the nanoscale (2-3 nm), up to much larger values (>100 nm), although locally the molecules are liquid-like.* Such lyotropic phases, in addition to their great relevance to understanding biological membrane structures, also have great potential in applications such as nanoencapsulation, nanoreactors, drug delivery, gene transfer, and delivery of Si-RNA to cells (Fong and Drummond, 2012, Leal et al., 2010). Apart from the bilayer lamellar Lα phase, all other fluid lyotropic mesophases are based upon ordered arrangements of curved interfaces, separating the amphiphiles from the water regions. These ordered curved phases may be divided into three main structural classes: 2D packings of cylindrical interfaces (discontinuous phases), 3D packings of saddle surfaces (bicontinuous phases), and 3D packings of spherical/ellipsoidal interfaces (discontinuous phases). Furthermore, each of these three classes occurs in two variants, either oil-in-water (type I), where the interfaces have net mean curvature toward the lipid hydrocarbon chain regions, or water-in-oil (inverse, type II), where the interfaces curve toward the water regions and away from the hydrocarbon chains (Figure 2.2). Type I curved mesophases generally break up into disordered micellar solutions upon high dilution in water. Type II mesophases, on the other hand, are usually stable in the presence of an excess water phase, and are therefore much more suitable for any applications where stable ordered self-assembled structures are required.
Gordon VD, Beales PA, Shearman GC, et al., 2014, Solid-Like Domains in Mixed Lipid Bilayers: Effect of Membrane Lamellarity and Transition Pathway, ADVANCES IN PLANAR LIPID BILAYERS AND LIPOSOMES, VOL 20, Vol: 20, Pages: 137-154, ISSN: 1554-4516
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- Citations: 3
Tang T-YD, Seddon AM, Jeworrek C, et al., 2014, The effects of pressure and temperature on the energetics and pivotal surface in a monoacylglycerol/water gyroid inverse bicontinuous cubic phase, SOFT MATTER, Vol: 10, Pages: 3009-3015, ISSN: 1744-683X
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- Citations: 10
Conn CE, Seddon JM, 2014, Nonlamellar Lipid Aggregates, LIPOSOMES, LIPID BILAYERS AND MODEL MEMBRANES: FROM BASIC RESEARCH TO APPLICATION, Editors: Pabst, Kucerka, Nieh, Katsaras, Publisher: CRC PRESS-TAYLOR & FRANCIS GROUP, Pages: 31-47, ISBN: 978-1-4665-0709-8
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- Citations: 1
Cook AG, Martinez-Felipe A, Brooks NJ, et al., 2013, New insights into the transitional behaviour of methyl-6-O-(<i>n</i>-dodecanoyl)-α-D-glucopyranoside using variable temperature FTIR spectroscopy and X-ray diffraction, LIQUID CRYSTALS, Vol: 40, Pages: 1817-1827, ISSN: 0267-8292
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- Citations: 27
Zahid NI, Conn CE, Brooks NJ, et al., 2013, Investigation of the Effect of Sugar Stereochemistry on Biologically Relevant Lyotropic Phases from Branched-Chain Synthetic Glycolipids by Small-Angle X-Ray Scattering, Langmuir
Synthetic branched-chain glycolipids are suitable as model systems to understand biological cell membranes, particularly since certain natural lipids possess chain branching. Herein, four branched-chain glycopyranosides namely 2-hexyl-decyl-α-D-glucopyranoside (α-Glc-OC10C6), 2-hexyl-decyl-β-D-glucopyranoside (β-Glc-OC10C6), 2-hexyl-decyl-α-D-galactopyranoside (α-Gal-OC10C6) and 2-hexyl-decyl-β-D-galactopyranoside (β-Gal-OC10C6) with a total alkyl chain length of 16 carbon atoms have been synthesized and their phase behaviour studied. The partial binary phase diagrams of these non-ionic surfactants in water were investigated by optical polarizing microscopy (OPM) and small-angle X-ray scattering (SAXS). The introduction of chain branching in the hydrocarbon chain region is shown to result in the formation of inverse structures such as the inverse hexagonal and inverse bicontinuous cubic phases. Comparison of the four compounds showed that they exhibited different polymorphism, especially in the thermotropic state, due to contributions from anomeric and epimeric effects according to their stereochemistry. The neat compound of α-Glc-OC10C6 exhibited a lamellar (Lα) phase whereas dry α-Gal-OC10C6formed an inverse bicontinuous cubic Ia3d (QIIG) phase. Both β-anomers of glucoside and galactoside adopted the inverse hexagonal phase (HII) in the dry state. Generally, in the presence of water, all four glycolipids formed inverse bicontinuous cubic Ia3d (QIIG) and Pn3m (QIID) phases over a wide temperature and concentration range. The formation of inverse non-lamellar phases by these Guerbet branched-chain glycosides confirms their potential as materials for novel biotechnological applications such as drug-delivery and crystallization of membrane proteins.
Miller D, Booth PJ, Seddon JM, et al., 2013, Protocell design through modular compartmentalization, JOURNAL OF THE ROYAL SOCIETY INTERFACE, Vol: 10, ISSN: 1742-5689
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- Citations: 16
Brooks N, Barriga H, McCarthy N, et al., 2013, Dynamic membrane structures at high pressure, 9th European-Biophysical-Societies-Association Congress, Publisher: SPRINGER, Pages: S118-S118, ISSN: 0175-7571
Tyler AII, Shearman GC, Parsons ES, et al., 2013, Tuning curvature in inverse micellar and bicontinuous cubic phases, 9th European-Biophysical-Societies-Association Congress, Publisher: SPRINGER, Pages: S140-S140, ISSN: 0175-7571
Zahid IN, Conn CE, Brooks NJ, et al., 2013, Effects of sugar stereochemistry on lyotropic mesophases of branched-chain synthetic glycolipids, 9th European-Biophysical-Societies-Association Congress, Publisher: SPRINGER, Pages: S132-S132, ISSN: 0175-7571
Seddon JM, 2013, Preface, FARADAY DISCUSSIONS, Vol: 161, Pages: 9-10, ISSN: 1359-6640
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- Citations: 15
Kulkarni CV, Ces O, Templer RH, et al., 2013, Pressure effects on a protein-lipid model membrane, SOFT MATTER, Vol: 9, Pages: 6525-6531, ISSN: 1744-683X
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- Citations: 8
Tang TYD, Brooks NJ, Jeworrek C, et al., 2012, Hydrostatic Pressure Effects on the Lamellar to Gyroid Cubic Phase Transition of Monolinolein at Limited Hydration, Langmuir
Cook AG, Wardell JL, Brooks NJ, et al., 2012, Non-symmetric liquid crystal dimer containing a carbohydrate-based moiety, Carbohydrate Research, Vol: 360, Pages: 78-83
The synthesis and characterisation of a novel non-symmetric liquid crystal dimer, 1-[3-O-(D-glucopyranos-3-yl)]-8-[(4-methoxyazobenzene-40-oxy)]octane is reported. This exhibits glassy behaviour and a highly interdigitated smectic A phase in which the aromatic and alkyl structural fragments overlap. Variable temperature infrared spectroscopy reveals that the strength and extent of hydrogen bonding within the system does not show a marked change at either the glass transition or at the smectic A-isotropic transition. This observation indicates that the smectic A-isotropic transition is driven by changes in the van der Waals interactions between the molecules while hydrogen bonded aggregates persist into the isotropic phase.
Sennoga CA, Yeh JSM, Alter J, et al., 2012, EVALUATION OF METHODS FOR SIZING AND COUNTING OF ULTRASOUND CONTRAST AGENTS, ULTRASOUND IN MEDICINE AND BIOLOGY, Vol: 38, Pages: 834-845, ISSN: 0301-5629
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- Citations: 39
Charalambous K, Booth PJ, Woscholski R, et al., 2012, Engineering <i>de Novo</i> Membrane-Mediated Protein-Protein Communication Networks, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: 5746-5749, ISSN: 0002-7863
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- Citations: 31
Shaw KP, Brooks NJ, Clarke JA, et al., 2012, Pressure – temperature phase behaviour of natural sphingomyelin extracts, Soft Matter, Vol: 8, Pages: 1070-1078
Sphingomyelin is the only sphingolipid occurring naturally in mammalian cells and can form up to 50% of the total phospholipid content of the myelin sheath which surrounds nerves. Having predominantly long, saturated acyl chains, it has a relatively high chain melting temperature and has been strongly associated with formation of lipid microdomains. Here, the lyotropic phase behaviour of sphingomyelin from three different natural sources (bovine brain, egg yolk and milk) in excess water is studied as a function of temperature and pressure by small- and wide-angle X-ray scattering, and solid state NMR. The different hydrocarbon chain length distributions of the three lipid extracts results in significant differences in their gel phase structure; both the bovine brain and egg yolk sphingomyelins can form a ripple gel phase but milk sphingomyelin forms an interdigitated gel phase due to the high degree of chain mismatch in its longer hydrocarbon chain components.
Brooks NJ, Ces O, Templer RH, et al., 2011, Pressure effects on lipid membrane structure and dynamics, CHEMISTRY AND PHYSICS OF LIPIDS, Vol: 164, Pages: 89-98, ISSN: 0009-3084
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- Citations: 54
Brooks NJ, Hamid HAA, Hashim R, et al., 2011, Thermotropic and lyotropic liquid crystalline phases of Guerbet branched-chain β-D-glucosides, Liquid Crystals, Vol: 38, Pages: 1725-1734
The effect of chain branching on glycolipid thermotropic and lyotropic phases was investigated for a series ofsynthetic β-D-glucosides derived from Guerbet alcohols, whose total hydrocarbon chain length ranged from C8 toC24. The compounds, which can be viewed as isosteric mimics for glycoglycerolipids, were synthesised in high purityand their liquid crystalline phases were studied using optical polarising microscopy (OPM), and small-angle X-raydiffraction.When dry, the shortest compound (total C8) exhibits a monotropic Lα phase while longer ones (C16 andC20) adopt inverse hexagonal HII phases. The C24 compound forms an ordered lamellar phase at room temperature,but exhibits a metastable HII phase upon cooling. Curiously the intermediate chain length homologue (C12) adoptsan isotropic inverse micellar (L2) phase in the dry state over the range of temperatures studied. Upon hydration,the C8 compound dissolves, and the C12 compound forms a fluid lamellar Lα phase. The C16 Guerbet glucoside (i.e.β-Glc-C10C6) exhibits an inverse bicontinuous cubic phase of space group Ia3d in excess water, never previouslyobserved in branched-chain lipids, and very seldom observed in excess water. The C20 compound remains in theHII phase upon hydrating, with the lattice parameter swelling substantially.
Shearman GC, Brooks NJ, Tiddy GJT, et al., 2011, A lyotropic inverse ribbon phase in a branched-chain polyoxyethylene surfactant: pressure effects, SOFT MATTER, Vol: 7, Pages: 4386-4390, ISSN: 1744-683X
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- Citations: 10
Tyler AII, Shearman GC, Brooks NJ, et al., 2011, Hydrostatic pressure effects on a hydrated lipid inverse micellar <i>Fd</i>3<i>m</i> cubic phase, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 13, Pages: 3033-3038, ISSN: 1463-9076
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- Citations: 15
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