scholarly journals Presence and persistence of a highly ordered lipid phase state in the avian stratum corneum

2018 ◽  
Vol 221 (11) ◽  
pp. jeb176438 ◽  
Author(s):  
Alex M. Champagne ◽  
Victoria A. Pigg ◽  
Heather C. Allen ◽  
Joseph B. Williams
Keyword(s):  
Stratum Corneum ◽  
Phase State ◽  
Lipid Phase

In Situ Monitoring of Lipid Phase State Make Target Lipid Mixtures Similar to Intercellular Lipid in the Stratum Corneum

2020 ◽  
Vol 122 (3) ◽  
pp. 1900171
Author(s):  
Mika Yoshimura Fujii ◽  
Katsuhiko Gato ◽  
Yosuke Ozawa ◽  
Hiroshi Hisada ◽  
Tatsuo Koide ◽  
...  
Keyword(s):  
Stratum Corneum ◽  
Phase State ◽  
In Situ Monitoring ◽  
Lipid Phase ◽  
Lipid Mixtures ◽  
Intercellular Lipid

Raman study of lipid phase state in freezing mammalian embryos and oocytes

Cryobiology ◽  
2018 ◽  
Vol 85 ◽  
pp. 165
Author(s):  
Konstantin A. Okotrub ◽  
Valentina I. Mokrousova ◽  
Sergei Ya. Amstislavsky ◽  
Nikolay V. Surovtsev
Keyword(s):  
Phase State ◽  
Lipid Phase ◽  
Mammalian Embryos ◽  
Raman Study

Mechanical and Microstructural Properties of Stratum Corneum

2002 ◽  
Vol 724 ◽  
Author(s):  
Kenneth S. Wu ◽  
William W. Van Osdol ◽  
Reinhold H. Dauskardt
Keyword(s):  
Stratum Corneum ◽  
Mechanical Behavior ◽  
Skin Surface ◽  
Lipid Phase ◽  
Peak Separation ◽  
Lipid Phase Transitions ◽  
Delamination Resistance ◽  
Energy Release Rates ◽  
Mechanical And Microstructural Properties ◽  
Increasing Temperature

AbstractA mechanics approach is presented to study the intercellular delamination resistance and mechanical behavior of stratum corneum (SC) tissue in the direction normal to the skin surface. The effects of temperature and hydration on debonding behavior were also explored. Such understanding, which includes the relationship of mechanical behavior to the underlying SC cellular structure, is essential for emerging transdermal drug delivery technologies. Fracture mechanics-based cantilever-beam specimens were used to determine reproducibly the energy release rates to quantify the cohesive strength of human SC. The debond resistance of fully hydrated SC was found to decrease with increasing temperature, while dehydrated SC exhibited a more complex variation with temperature. Stress-separation tests showed that fracture energies and peak separation stresses decreased with increasing temperature and hydration, although the SC modulus varied only marginally with temperature and hydration. Results are described in terms of microstructural changes associated with hydrophilic regions and intercellular lipid phase transitions.

scholarly journals Lipid Influence on the Structure of the Light Harvesting B 800—850 Proteins

1987 ◽  
Vol 42 (1-2) ◽  
pp. 109-117
Author(s):  
Joachim Peschke ◽  
Helmuth Möhwald
Keyword(s):  
Phase State ◽  
Transient Absorption ◽  
Photosynthetic Bacterium ◽  
Head Group ◽  
Lipid Phase ◽  
Elastic Model ◽  
Structural Protein ◽  
Protein Change ◽  
Lipid Environment ◽  
Lipid Head Group

Abstract Interaction of the antenna protein B 800-850 with the lipid environment and with the reaction center of the photosynthetic bacterium Rhodopseudomonas sphaeroides is studied by fluorescence spectroscopy, transient absorption techniques, light scattering and electron microscopy. Using vesicles of synthetic phospholipids it is shown that solidification of the m em brane causes a structural protein change evident from a reduction in fluorescence quantum yield. The change occurs at a tem perature up to 5 °C below that corresponding to the gel/fluid transition tem perature and indicates local melting. The structural change is not specific for the lipid head group nor chain length (investigated for lengths of 12 to 16 CH2 groups) and can be understood applying a simple elastic model. It can also be included isothermally by changing the ionic milied and thus varying the lipid phase state. Energy transfer LHCP→RC is proven to be highly efficient in model m em branes and is not affected by the existence of a phase transition. This indicates two LHCP fractions one tightly - and one non-bound to the RC.

Local Temperature Rises Influence In Vivo Electroporation Pore Development: A Numerical Stratum Corneum Lipid Phase Transition Model

2007 ◽  
Vol 129 (5) ◽  
pp. 712-721 ◽  
Author(s):  
S. M. Becker ◽  
A. V. Kuznetsov
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Stratum Corneum ◽  
Joule Heating ◽  
Lipid Phase ◽  
Transition Model ◽  
Lipid Phase Transition ◽  
Stratum Corneum Lipid ◽  
Lipid Melting

Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. Electroporation temporarily destabilizes the structure of the outer skin layer, the stratum corneum, by creating microscopic pores through which agents, ordinarily unable to pass into the skin, are able to pass through this outer barrier. Long duration electroporation pulses can cause localized temperature rises, which result in thermotropic phase transitions within the lipid bilayer matrix of the stratum corneum. This paper focuses on electroporation pore development resulting from localized Joule heating. This study presents a theoretical model of electroporation, which incorporates stratum corneum lipid melting with electrical and thermal energy equations. A transient finite volume model is developed representing electroporation of in vivo human skin, in which stratum corneum lipid phase transitions are modeled as a series of melting processes. The results confirm that applied voltage to the skin results in high current densities within the less resistive regions of the stratum corneum. The model captures highly localized Joule heating within the stratum corneum and subsequent temperature rises, which propagate radially outward. Electroporation pore development resulting from the decrease in resistance associated with lipid melting is captured by the lipid phase transition model. As the effective pore radius grows, current density and subsequent Joule heating values decrease.

scholarly journals Lipid droplet phase transition in freezing cat embryos and oocytes probed by Raman spectroscopy

2018 ◽  
Author(s):  
K.A. Okotrub ◽  
V.I. Mokrousova ◽  
S.Y. Amstislavsky ◽  
N.V. Surovtsev
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
Lipid Droplets ◽  
Phase State ◽  
Domestic Cat ◽  
Lipid Phase ◽  
Lipid Phase Transition ◽  
Lipid Molecule ◽  
Early Embryos ◽  
Lipid Unsaturation

ABSTRACTEmbryo and oocyte cryopreservation is a widely used technology for cryopreservation of genetic resources. One challenging limitation of this technology is the cell damage during freezing associated with the intracellular lipid droplets. We exploit a Raman spectroscopy to investigate the freezing of cumulus-oocyte complexes, mature oocytes and early embryos of a domestic cat. All these cells are rich in lipids. The degree of lipid unsaturation, lipid phase transition from liquid-like disordered to solid-like ordered state (main transition) and triglyceride polymorphic state are studied. For all cells examined, the average degree of lipid unsaturation is estimated about 1.3 (with ±20 % deviation) double bonds per acyl chain. The onset of the main lipid phase transition occurs in a temperature range from −10 to +4 °C and does not depend significantly on the cell type. It is found that lipid droplets in cumulus-oocyte complexes undergo an abrupt lipid crystallization, which not completely correlate with the ordering of lipid molecule acyl chains. In the case of mature oocytes and early embryos obtainedin vitrofrom cumulus-oocyte complexes, the lipid phase transition is broadened. In frozen state lipid droplets inside the cumulus-oocyte complexes have higher content of triglyceride polymorphic β and β′ phases (∼66%) than it is estimated for the mature oocytes and the early embryos (∼50%). For the first time, to our knowledge, temperature evolution of lipid droplets phase state is examined. Raman spectroscopy is proved as a prospective tool forin situmonitoring of lipid phase state in single embryo/oocyte during freezing.

Stratum corneum lipid phase transitions and water barrier properties

Biochemistry ◽  
1987 ◽  
Vol 26 (8) ◽  
pp. 2382-2388 ◽  
Author(s):  
Guia M. Golden ◽  
Donald B. Guzek ◽  
Alane E. Kennedy ◽  
James E. McKie ◽  
Russell O. Potts
Keyword(s):  
Phase Transitions ◽  
Stratum Corneum ◽  
Barrier Properties ◽  
Lipid Phase ◽  
Water Barrier ◽  
Lipid Phase Transitions ◽  
Stratum Corneum Lipid
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