Ionic Liquid Expedites Partition of Curcumin into Solid Gel Phase but Discourages Partition into Liquid Crystalline Phase of 1,2-Dimyristoyl-sn-glycero-3-phosphocholine Liposomes

2013 ◽  
Vol 117 (33) ◽  
pp. 9699-9708 ◽  
Author(s):  
Elsy D. El Khoury ◽  
Digambara Patra
Keyword(s):  
Ionic Liquid ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Gel Phase

Liquid crystalline phase behavior and fiber spinning of cellulose/ionic liquid/halloysite nanotubes dispersions

2014 ◽  
Vol 2 (20) ◽  
pp. 7327 ◽  
Author(s):  
Zhiqiang Luo ◽  
Aiqing Wang ◽  
Chunzheng Wang ◽  
Weichao Qin ◽  
Ningning Zhao ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Phase Behavior ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Halloysite Nanotubes ◽  
Fiber Spinning ◽  
Liquid Crystalline Phase

Structure and Thermotropic Behaviour of Mixed Choline Phospholipid Model Membranes

1997 ◽  
Vol 30 (5) ◽  
pp. 776-780 ◽  
Author(s):  
G. Degovics ◽  
A. Latal ◽  
E. Prenner ◽  
M. Kriechbaum ◽  
K. Lohner
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Lipid Vesicles ◽  
Hydrocarbon Chain ◽  
Liquid Crystalline Phase ◽  
Lipid Monolayer ◽  
Repeat Distance ◽  
Molar Ratios ◽  
Gel Phase

Phosphatidylcholines and sphingomyelins are among the most abundant lipids in mammalian cell membranes, being major components of platelets or erythrocytes, and of the lipid monolayer of lipoproteins. General efforts have been devoted to the elucidation of the interaction of the ubiquitous membrane component cholesterol with these choline phospholipids, but fewer studies have been reported on the interaction between the phospholipids themselves. A gel to liquid-crystalline phase transition was observed for pure sphingomyelin liposomes at physiological temperature, while palmitoyloleoyl phosphatidylcholine adopts a liquid-crystalline phase in the temperature range 273–323 K. The two phospholipids are miscible at all molar ratios in the liquid-crystalline phase, characterized by very similar lamellar repeat distances for all binary lipid mixtures. The gel phase of pure sphingolipid liposomes exhibited a markedly smaller lamellar repeat distance as compared to mixed lipid vesicles, which increased slightly with temperature for the pure sphingomyelin (66.9–69.2 Å). Concomitantly, altered hydrocarbon chain packing was observed. Similar diffractograms were obtained in the presence of 10 mol% phosphatidylcholine. However, in the composition range between 20 and 60 mol% phosphatidylcholine in the phosphatidylcholine–sphingomyelin admixture, the lamellar repeat distance in the gel phase was markedly increased and remained almost constant (around 75 Å) below the phase transition.

Monodispersity and ordering of semiconductor quantum dots synthesised in ionic liquid crystalline phase of cadmium alkanoates

2013 ◽  
Vol 40 (7) ◽  
pp. 980-988 ◽  
Author(s):  
G. Klimusheva ◽  
I. Dmitruk ◽  
T. Mirnaya ◽  
A. Tolochko ◽  
S. Bugaychuk ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ionic Liquid ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Semiconductor Quantum Dots ◽  
Liquid Crystalline Phase

scholarly journals Formation of unilamellar dipalmitoylphosphatidylcholine vesicles promoted by Ca2+ions: A small-angle neutron scattering study

2007 ◽  
Vol 21 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Daniela Uhríková ◽  
José Teixeira ◽  
Adrián Lengyel ◽  
László Almásy ◽  
Pavol Balgavý
Keyword(s):  
Neutron Scattering ◽  
Lipid Bilayer ◽  
Small Angle ◽  
Crystalline Phase ◽  
Small Angle Neutron Scattering ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Bilayer Thickness ◽  
Unilamellar Vesicles ◽  
Gel Phase

Dipalmitoylphosphatidylcholine (DPPC) was hydrated in 0.2–60 mM solution of CaCl2in heavy water and thoroughly homogenized by freezing-thawing process. Small-angle neutron scattering (SANS) shows formation of unilamellar vesicles in the range 1–60 mM of CaCl2. From the Kratky–Porod plot ln [I(Q)Q2] vs.Q2of SANS intensityI(Q)in the range of scattering vectorsQcorresponding to the interval 0.001 Å−2≤Q2≤0.006 Å−2, the vesicle bilayer radius of gyrationRgand the bilayer thickness parameterdgwere obtained. The structure of the bilayer displays different behavior for the gel phase and the liquid-crystalline phase: In the gel phase (at 20°C), the values ofdgindicate nonlinear changes in the lipid bilayer thickness, with a maximum at ~5 mM CaCl2. In the liquid-crystalline phase (at 60°C), the parameter of the lipid bilayer thicknessdg=43.2±0.3 Å is constant within the concentration range 1≤cCa≤40 mM. Vesicles prepared at 60 mM CaCl2show within experimental error, the same values ofdgas pure DPPC unilamellar vesicles prepared by extrusion using polycarbonate filter with pores of diameter 500 Å.

scholarly journals Lamellar Liquid Crystalline Phase Formed by Triblock Copolymer L64 in 1-Butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid

2012 ◽  
Vol 28 (06) ◽  
pp. 1411-1417 ◽  
Author(s):  
ZHAO Xue-Yan ◽  
◽  
CAO Yu-Rong ◽  
CAO Gui-Rong ◽  
XIAO Rui-Jie ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Crystalline Phase ◽  
Triblock Copolymer ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase

Lyotropic liquid crystalline phase behaviour in amphiphile–protic ionic liquid systems

2012 ◽  
Vol 14 (11) ◽  
pp. 3825 ◽  
Author(s):  
Zhengfei Chen ◽  
Tamar L. Greaves ◽  
Celesta Fong ◽  
Rachel A. Caruso ◽  
Calum J. Drummond
Keyword(s):  
Ionic Liquid ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Phase Behaviour ◽  
Liquid Crystalline Phase ◽  
Protic Ionic Liquid ◽  
Liquid Systems

Mixtures of semisynthetic species of cerebroside sulfate with dipalmitoyl phosphatidylcholine. Thermotropic phase behavior and permeability

1990 ◽  
Vol 68 (1) ◽  
pp. 70-82 ◽  
Author(s):  
J. M. Boggs ◽  
D. Mulholland ◽  
K. M. Koshy
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystalline Phase ◽  
Spin Label ◽  
Liquid Crystalline ◽  
Water Soluble ◽  
Liquid Crystalline Phase ◽  
Low Permeability ◽  
Scanning Calorimetry ◽  
Dipalmitoyl Phosphatidylcholine ◽  
Gel Phase

The phase behavior of mixtures of dipalmitoyl phosphatidylcholine (DPPC) with semisynthetic species of cerebroside sulfate (CBS) containing palmitic acid (C16:0-CBS) or lignoceric acid (C24:0-CBS) in 0.1 M KCl was studied using differential scanning calorimetry. DPPC and C16:0-CBS were miscible in all proportions in the gel phase above 10 mol% CBS and in the liquid-crystalline phase. However, C24:0-CBS was less miscible with DPPC over a wide concentration range in the gel phase. At high CBS concentrations it was probably also not entirely miscible with DPPC in the liquid-crystalline phase. Small amounts of both species of CBS lowered the transition temperature and enthalpy of DPPC, suggesting that they are more soluble in the liquid-crystalline phase of DPPC than the gel phase. The transition temperature at higher CBS concentrations was also less than expected, especially after cycling through the phase transition in the case of C24:0-CBS, suggesting that mixing with DPPC inhibited the intermolecular hydrogen bonding interactions and dehydration of CBS. In C24:0-CBS–DPPC mixtures several populations were present over a wide compositional range, including two solid-solid solutions of fixed composition. At high C24:0-CBS concentrations some C24:0-CBS also phase separated out of the mixture. Structural considerations suggested that the C24:0-CBS which is mixed with DPPC must be interdigitated into the DPPC bilayer. Other populations that are present may have a different structural organization. A fatty acid spin label in these mixtures was a little less ordered than in either lipid by itself. The permeability of these lipids, as well as the two asymmetric species 1-stearoyl-2-caproyl phosphatidylcholine and 1-stearoyl-2-myristoyl phosphatidylcholine (18:10PC and 18:14PC), to a water-soluble spin label tempocholine chloride was also measured. The studies with 18:10PC and 18:14PC indicated that both triple-chain mixed interdigitated bilayers and double-chain partially interdigitated bilayers can trap water-soluble substances and have low permeability. Both species of CBS could also entrap the spin label and had low permeability at 4 °C. However, they rapidly lost the entrapped compound when they transformed into their stable dehydrated phases or into the liquid-crystalline phase. Mixing with DPPC prevented both of these losses. These studies supported the conclusion that a significant amount of the CBS was mixed with the DPPC and that this mixing prevented the dehydration changes which CBS undergoes by itself. They also suggested that the C24:0-CBS can pack with the DPPC in the liquid-crystalline phase in a regular way which must involve inter-digitation of the long C24:0 chain into the DPPC bilayer.Key words: sulfatide, phosphatidylcholine, phase diagram, differential scanning calorimetry, interdigitated bilayer.

scholarly journals Electron transfer studies of a conventional redox probe in human sweat and saliva bio-mimicking conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Krishnaveni ◽  
V. Ganesh
Keyword(s):  
Electron Transfer ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Redox Couple ◽  
Liquid Crystalline Phase ◽  
Transfer Reactions ◽  
Redox Probe ◽  
Human Sweat

AbstractModern day hospital treatments aim at developing electrochemical biosensors for early diagnosis of diseases using unconventional human bio-fluids like sweat and saliva by monitoring the electron transfer reactions of target analytes. Such kinds of health care diagnostics primarily avoid the usage of human blood and urine samples. In this context, here we have investigated the electron transfer reaction of a well-known and commonly used redox probe namely, potassium ferro/ferri cyanide by employing artificially simulated bio-mimics of human sweat and saliva as unconventional electrolytes. Typically, electron transfer characteristics of the redox couple, [Fe(CN)6]3−/4− are investigated using electrochemical techniques like cyclic voltammetry and electrochemical impedance spectroscopy. Many different kinetic parameters are determined and compared with the conventional system. In addition, such electron transfer reactions have also been studied using a lyotropic liquid crystalline phase comprising of Triton X-100 and water in which the aqueous phase is replaced with either human sweat or saliva bio-mimics. From these studies, we find out the electron transfer reaction of [Fe(CN)6]3−/4− redox couple is completely diffusion controlled on both Au and Pt disc shaped electrodes in presence of sweat and saliva bio-mimic solutions. Moreover, the reaction is partially blocked by the presence of lyotropic liquid crystalline phase consisting of sweat and saliva bio-mimics indicating the predominant charge transfer controlled process for the redox probe. However, the rate constant values associated with the electron transfer reaction are drastically reduced in presence of liquid crystalline phase. These studies are essentially carried out to assess the effect of sweat and saliva on the electrochemistry of Fe2+/3+ redox couple.

Liquid crystalline phase transitions in hexakis(4-(4′-heptyloxy)biphenoxy)cyclotriphosphazene

1995 ◽  
Vol 18 (5) ◽  
pp. 795-800 ◽  
Author(s):  
K. Moriya ◽  
H. Mizusaki ◽  
M. Kato ◽  
S. Yano ◽  
M. Kajiwara
Keyword(s):  
Phase Transitions ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase
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