A Novel Framework for In-House High throughput Measurements of Lipid Phase Behaviour

Amphiphilic compounds are used in a variety of applications due to their lyotropic liquid-crystalline phase formation, however only a limited number of compounds, in a potentially limitless field, are currently in use. A library of organic amphiphilic compounds was synthesised consisting of glucose, galactose, lactose, xylose and mannose head groups and double and triple-chain hydrophobic tails. A modular, high-throughput approach was developed, whereby head and tail components were conjugated using the copper-catalysed azide–alkyne cycloaddition (CuAAC) reaction. The tails were synthesised from two core alkyne-tethered intermediates, which were subsequently functionalised with hydrocarbon chains varying in length and degree of unsaturation and branching, while the five sugar head groups were selected with ranging substitution patterns and anomeric linkages. A library of 80 amphiphiles was subsequently produced, using a 24-vial array, with the majority formed in very good to excellent yields. A preliminary assessment of the liquid-crystalline phase behaviour is also presented.

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Lipid phase behaviour under steady state conditions

Faraday Discussions ◽

10.1039/c2fd20079a ◽

2013 ◽

Vol 161 ◽

pp. 151-166 ◽

Cited By ~ 8

Author(s):

Christoffer Åberg ◽

Emma Sparr ◽

Håkan Wennerström

Keyword(s):

Steady State ◽

Phase Behaviour ◽

Lipid Phase

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Differential scanning calorimetry and X-ray diffraction studies of a series of synthetic β-D-galactosyl diacylglycerols

Biochemistry and Cell Biology ◽

10.1139/o91-128 ◽

1991 ◽

Vol 69 (12) ◽

pp. 863-867 ◽

Cited By ~ 23

Author(s):

D. A. Mannock ◽

R. N. McElhaney

Keyword(s):

Phase Transition ◽

Differential Scanning Calorimetry ◽

Phase Behaviour ◽

Lipid Phase ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Phase Transition Temperatures ◽

Bonding Properties ◽

Lower Temperature

We have investigated the physical properties of a homologous series of synthetic, saturated 1,2-di-O-acyl-3-O-(β-D-galactopyranosyl)-sn-glycerols using calorimetry and X-ray diffraction. Unannealed aqueous dispersions of these compounds exhibit a lower temperature, moderately energetic, chain-melting (Lβ/Lα phase transition and a higher temperature, weakly energetic, bilayer/nonbilayer phase transition. On annealing below the Lβ/Lα phase transition, the Lβ phase converts to an LC phase, which may undergo a highly energetic LC/Lα or LC/HII phase transition at very high temperatures on reheating. The temperatures of these phase transitions are higher than those seen in the corresponding α- and β-D-glucosyl diacylglycerols. However, the Lβ/Lα and bilayer/nonbilayer phase transition temperatures of the β-D-galactosyl diacylglycerols are lower than those of the corresponding diacyl phosphatidylethanolamines. These observations are discussed in terms of the hydration and hydrogen bonding properties of their respective headgroups.Key words: differential scanning calorimetry, low-angle x-ray diffraction, glycolipids, galactolipids, lipid phase behaviour.

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NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY AND LIPID PHASE BEHAVIOUR AND LIPID DIFFUSION

Advances in Lipid Methodology ◽

10.1533/9780857098009.133 ◽

2012 ◽

pp. 133-209 ◽

Cited By ~ 1

Author(s):

Göran Lindblom

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Nuclear Magnetic Resonance Spectroscopy ◽

Phase Behaviour ◽

Lipid Phase ◽

Resonance Spectroscopy ◽

Lipid Diffusion ◽

Nuclear Magnetic

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Fluorescent probe partitioning in giant unilamellar vesicles of ‘lipid raft’ mixtures

Biochemical Journal ◽

10.1042/bj20100516 ◽

2010 ◽

Vol 430 (3) ◽

pp. 415-423 ◽

Cited By ~ 78

Author(s):

Janos Juhasz ◽

James H. Davis ◽

Frances J. Sharom

Keyword(s):

Fluorescent Probe ◽

Lipid Bilayer ◽

Fluorescent Probes ◽

Phase Behaviour ◽

Model Systems ◽

Fluorescence Probes ◽

Lipid Phase ◽

Giant Unilamellar Vesicles ◽

Unilamellar Vesicles ◽

Lipid Mixture

Direct visualization of raft-like lo (liquid-ordered) domains in model systems and cells using microscopic techniques requires fluorescence probes with known partitioning preference for one of the phases present. However, fluorescent probes may display dissimilar partitioning preferences in different lipid sys-tems and can also affect the phase behaviour of the host lipid bilayer. Therefore a detailed understanding of the behaviour of fluorescent probes in defined lipid bilayer systems with known phase behaviour is essential before they can be used for identifying domain phase states. Using giant unilamellar vesicles composed of the ternary lipid mixture DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine)/DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine)/cholesterol, for which the phase behaviour is known, we examined nine commonly used fluorescent probes using confocal fluorescence microscopy. The partitioning preference of each probe was assigned either on the basis of quantification of the domain area fractions or by using a well-characterized ld (liquid-disordered)-phase marker. Fluorescent probes were examined both individually and using dual or triple labelling approaches. Most of the probes partitioned individually into the ld phase, whereas only NAP (naphtho[2,3-a]pyrene) and NBD-DPPE [1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-(7-nitro-2-1,3-benzoxadiazol-4-yl] preferred the lo phase. We found that Rh-DPPE (Lissamine™ rhodamine B–1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine) increased the miscibility transition temperature, Tmix. Interestingly, the partitioning of DiIC18 (1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate) was influenced by Bodipy®-PC [2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexa-decanoyl-sn-glycero-3-phosphocholine]. The specific use of each of the fluorescent probes is determined by its photostability, partitioning preference, ability to detect lipid phase separations and induced change in Tmix. We demonstrate the importance of testing a specific fluorescent probe in a given model membrane system, rather than assuming that it labels a particular lipid phase.

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Cold-induced lipid phase transitions

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1990.0031 ◽

1990 ◽

Vol 326 (1237) ◽

pp. 555-570 ◽

Cited By ~ 25

Keyword(s):

Low Temperatures ◽

Membrane Lipids ◽

Weak Interactions ◽

Protective Action ◽

Biological Membranes ◽

Membrane Lipid ◽

Phase Behaviour ◽

Lipid Phase ◽

Aqueous Environment ◽

Factors Affecting

The structural organization of biological membranes is largely determined by the weak interactions existing between their components and between these components and their aqueous environment. These interactions are particularly sensitive to changes in temperature and hydration. The factors influencing membrane lipid phase behaviour are briefly reviewed and used to develop a phase-separation model describing the response of biological membranes to stress. The factors affecting the interaction of cryoprotectants with membrane lipids are explored and their role in the stabilization of membrane organization at low temperatures discussed. It is suggested that the basis of their protective action lies in an ability to preserve the balance of interactions between membrane components at low temperatures at a level similar to that existing under physiological conditions.

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