Localization of methyl-branched ceramide [EOS] species within the long-periodicity phase in stratum corneum lipid model membranes: A neutron diffraction study.
The outermost layer of the mammalian skin, the stratum corneum (SC), is a very thin structure and realizes simultaneously the main barrier properties. The penetration barrier for xenobiotica is mostly represented by a complex lipid matrix. There is great interest in the subject of getting information about the arrangement of the lipids, which are mainly ceramides (CER), free fatty acids (FFA) and cholesterol (CHOL). SC lipid model membranes containing synthetically derived lipids in a non-physiological ratio were investigated. To compare the study to a former experiment, a methyl-branched ceramide [EOS] species in presence of the ultra-long chain CER[AP], CHOL and behenic acid (23/10/33/33, wt%) was applied. The membrane structure was studied using the very versatile technique of neutron diffraction. We were able to identify a long-periodicity phase (LPP) with a size of 114Å or 118Å with CER[EOS]-br in a ratio of >60wt% of the ceramides. Furthermore, we figured out two additional coexisting short-periodicity phases (SPP) with repeat distances of 48Å and 45Å, respectively. Partial deuterations of CER[EOS]-br and CER[AP] enabled the localization of the molecules within the multiphase system. CER[EOS]-d3 was present in the LPP, but absent in both SPP. CER[AP]-d3 was determined in both short phases but not localized within the LPP. Besides, we revealed influences of humidity and time with respect to the long-periodicity phase.
Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany.
Adina
A
Eichner
Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany.
Stefan
S
Sonnenberger
Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany.
Bodo
B
Dobner
Institute of Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany.
Thomas
T
Hauß
Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; DR. KADE Pharmazeutische Fabrik GmbH, 12277 Berlin, Germany.
Annett
A
Schroeter
Institute of Pharmacy, Martin Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany; Institute of Applied Dermatopharmacy at the Martin Luther University Halle-Wittenberg, 06120 Halle/Saale, Germany. Electronic address: reinhard.neubert@pharmazie.uni-halle.de.
Reinhard H H
RHH
Neubert
D000818:Animals; D002518:Ceramides / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry*; D003903:Deuterium; D004817:Epidermis / Q000737:chemistry; D005227:Fatty Acids / Q000737:chemistry*; D005230:Fatty Acids, Nonesterified / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D033363:Neutron Diffraction
D002518:Ceramides; D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D008051:Lipid Bilayers; D002784:Cholesterol; D003903:Deuterium; C007547:behenic acid
Ceramides; Lipid model membrane; Long-periodicity phase; Neutron diffraction; Short- periodicity phase; Stratum corneum