Lateral phase separation of phospholipids as a basis for increased permeability of membranes towards fluorescein and other chemical species

1984 ◽  
Vol 80 (3) ◽  
pp. 249-256 ◽  
Author(s):  
Gillian M. K. Humphries ◽  
John P. Lovejoy
Keyword(s):  
Phase Separation ◽  
Chemical Species ◽  
Lateral Phase Separation

scholarly journals Adhesion-induced lateral phase separation in membranes

2000 ◽  
Vol 3 (3) ◽  
pp. 259-271 ◽  
Author(s):  
S. Komura ◽  
D. Andelman
Keyword(s):  
Phase Separation ◽  
Lateral Phase Separation

scholarly journals A Personal Journey across Fluorescent Sensing and Logic Associated with Polymers of Various Kinds

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1351 ◽  
Author(s):  
Chao-Yi Yao ◽  
Seiichi Uchiyama ◽  
A. Prasanna de Silva
Keyword(s):  
Phase Separation ◽  
Metal Ion ◽  
Chemical Species ◽  
Polymer Science ◽  
Molecular Sensing ◽  
Fluorescent Sensing ◽  
Molecular Logic ◽  
Fluorescent Molecular Sensing ◽  
Molecular Scale ◽  
Identification Tags

Our experiences concerning fluorescent molecular sensing and logic devices and their intersections with polymer science are the foci of this brief review. Proton-, metal ion- and polarity-responsive cases of these devices are placed in polymeric micro- or nano-environments, some of which involve phase separation. This leads to mapping of chemical species on the nanoscale. These devices also take advantage of thermal properties of some polymers in water in order to reincarnate themselves as thermometers. When the phase separation leads to particles, the latter can be labelled with identification tags based on molecular logic. Such particles also give rise to reusable sensors, although molecular-scale resolution is sacrificed in the process. Polymeric nano-environments also help to organize rather complex molecular logic systems from their simple components. Overall, our little experiences suggest that researchers in sensing and logic would benefit if they assimilate polymer concepts.

scholarly journals Amorphous Mixtures of Ice and C60 Fullerene

2020 ◽  
Author(s):  
Siriney Halukeerthi ◽  
Jacob J. Shephard ◽  
Sukhpreet Talewar ◽  
John S. O. Evans ◽  
Alexander Rosu-Finsen ◽  
...  
Keyword(s):  
Phase Separation ◽  
Percolation Threshold ◽  
Thermal Desorption ◽  
Crystallization Temperature ◽  
Space Exploration ◽  
Chemical Species ◽  
C60 Fullerene ◽  
Volume Percent ◽  
Water Desorption ◽  
Amorphous Ice

Carbon and ice make up a substantial proportion of our Universe. Recent space exploration has shown that these two chemical species often coexist including on comets, asteroids and in the interstellar medium. Here we prepare mixtures of C<sub>60</sub> fullerene and H<sub>2</sub>O by vapor co-deposition at 90 K with molar C<sub>60</sub>:H<sub>2</sub>O ratios ranging from 1:1254 to 1:5. The C<sub>60</sub> percolation threshold is found between the 1:132 and 1:48 samples, corresponding to a transition from matrix-isolated C<sub>60</sub> molecules to percolating C<sub>60</sub> domains that confine the H<sub>2</sub>O. Below this threshold, the crystallization and thermal desorption properties of H<sub>2</sub>O are not significantly affected by the C<sub>60</sub>, whereas the crystallization temperature of H<sub>2</sub>O is shifted towards higher temperatures for the C<sub>60</sub>-rich samples. These C<sub>60</sub>-rich samples also display exotherms corresponding to the crystallization of C<sub>60</sub> as the two components undergo phase separation. More than 60 volume percent C<sub>60</sub> is required to significantly affect the desorption properties of H<sub>2</sub>O. A thick blanket of C<sub>60</sub> on top of pure amorphous ice is found to display large cracks due to water desorption. These findings may help understand the recently observed unusual surface features and the H<sub>2</sub>O weather cycle on the 67P/Churyumov–Gerasimenko comet.

scholarly journals Phase Diagram of Purified CNS Myelin Reveals Continuous Transformation between Expanded and Compacted Lamellar States

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 670
Author(s):  
Julio M. Pusterla ◽  
Emanuel Schneck ◽  
Rafael G. Oliveira
Keyword(s):  
Phase Diagram ◽  
Phase Separation ◽  
Isothermal Transformation ◽  
Phase Behaviour ◽  
Apparent Difference ◽  
X Ray Diffraction ◽  
Lateral Phase Separation ◽  
Diffraction Peaks ◽  
Low Ionic Strength ◽  
Detergent Resistant Membrane

Purified myelin membranes (PMMs) are the starting material for biochemical studies, from individual components up to the isolation of detergent-resistant membrane (DRM) fractions or detergent-insoluble glycosphingolipid (DIG) fractions, which are commonly believed to resemble physiological lipid rafts. The normal DIG isolation protocol involves the extraction of lipids under moderate cooling. The isolation of PMMs also involves the cooling of myelin as well as exposure to low ionic strength (IS). Here, we addressed the combined influence of cooling and IS on the structure of PMMs. The phase behaviour was investigated by small angle X-ray diffraction. Analysis of the diffraction peaks revealed the lamellar periodicity ( d ), the number of periodically correlated bilayers ( N ), and the relatives fractions of each phase. Departure from physiological conditions induced a phase separation in myelin. The effect of monovalent and divalent ions was also compared at equivalent IS, showing a differential effect, and phase diagrams for both ion types were established—Ca2+ induced the well-known over-compacted phase, but additionally we also found an expanded phase at low IS. Na+ promoted phase separation, and also induced over-compaction at sufficiently high IS. Finally, exploring the whole phase diagram, we found evidence for the direct isothermal transformation from the expanded to the compacted phase, suggesting that both phases could in fact originate from the identical primary lateral phase separation, whereas the apparent difference lies in the inter-bilayer interaction that is modulated by the ionic milieu.

Calcium-induced lateral phase separation in phosphatidic acid/phosphatidylcholine monolayers as revealed by fluorescence microscopy

Biochemistry ◽  
1988 ◽  
Vol 27 (9) ◽  
pp. 3433-3437 ◽  
Author(s):  
Kari K. Eklund ◽  
Jorma Vuorinen ◽  
Jukka Mikkola ◽  
Jorma A. Virtanen ◽  
Paavo K. J. Kinnunen
Keyword(s):  
Phase Separation ◽  
Fluorescence Microscopy ◽  
Phosphatidic Acid ◽  
Lateral Phase Separation

Lateral and Vertical Phase Separation Control of Thin-film Structures for Photovoltaics

2001 ◽  
Vol 665 ◽  
Author(s):  
A. C. Arias ◽  
J. D. MacKenzie ◽  
N. Corcoran ◽  
R. H. Friend
Keyword(s):  
Phase Separation ◽  
Spin Coating ◽  
Solution Viscosity ◽  
Separation Control ◽  
Nanometer Scale ◽  
Length Scale ◽  
Photovoltaic Devices ◽  
Photovoltaic Properties ◽  
Lateral Phase Separation ◽  
Photoluminescence Efficiency

ABSTRACTInvestigations on microscopic and photovoltaic properties of polyfluorene blends are presented here. The length scale of lateral phase separation is manipulated by control of solvent evaporation conditions. Photoluminescence efficiency measurements show that charge transfer is more effective in blends phase separated on the nanometer scale. Vertically segregated structures are obtained by a combination of solution viscosity and spin coating conditions. The external quantum efficiency of photovoltaic devices fabricated with vertically segregated blend is found to be 4 times higher than that of devices made with laterally segregated blends.

Lateral phase separation based on chirality in a polymerizable lipid and its influence on formation of tubular microstructures

1988 ◽  
Vol 47 (2) ◽  
pp. 135-148 ◽  
Author(s):  
Alok Singh ◽  
Thomas G. Burke ◽  
Jeffrey M. Calvert ◽  
Jacque H. Georger ◽  
Barbara Herendeen ◽  
...  
Keyword(s):  
Phase Separation ◽  
Lateral Phase Separation

Changes in Vesicle Morphology Induced by Lateral Phase Separation Modulate Phospholipase A2Activity†

Biochemistry ◽  
1997 ◽  
Vol 36 (34) ◽  
pp. 10551-10557 ◽  
Author(s):  
W. Richard Burack ◽  
Andrew R. G. Dibble ◽  
Margaretta M. Allietta ◽  
Rodney L. Biltonen
Keyword(s):  
Phase Separation ◽  
Lateral Phase Separation

Theory of protein-induced lateral phase separation in lipid membranes

1989 ◽  
Vol 14 (1) ◽  
pp. 79-95 ◽  
Author(s):  
Maria M. Sperotto ◽  
John Hjort Ipsen ◽  
Ole G. Mouritsen
Keyword(s):  
Phase Separation ◽  
Lipid Membranes ◽  
Lateral Phase Separation
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