The intercellular lipid structure of the stratum corneum (SC) plays a key role in skin barrier function. A depth profile of the intercellular lipid conformation and the lipid lateral packing order were measured in vivo in the human SC using confocal Raman microscopy. The depth profiles of the 2880 cm(-1)/2850 cm(-1) peak ratio intensity, which represent the C-H stretching and lateral packing order of lipids, and the 1080 cm(-1)/(1130 cm(-1) + 1060 cm(-1)) peak ratio, which represents the C-C skeleton vibration and trans-gauche conformation order of lipids, were investigated. The influence of keratin on the lipid peaks at 2850 cm(-1) and 2880 cm(-1) was excluded by the developed mathematical algorithm. The results show that the trans-conformation and lateral packing order of the intercellular lipids reach their maximum value in the SC at 20-40% of its depth and then decrease towards the stratum granulosum. These results show that at a depth of 20-40% (normally corresponding to a depth of 4-8 μm) the SC exhibits the most ordered lipids and therefore the highest skin barrier function. The lateral packing of lipids is more disordered on the surface and in the deeper parts of the SC, which may be associated with a reduced skin barrier function.
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http://dx.doi.org/10.1039/c5an02373d | DOI Listing |
Nat Commun
January 2025
Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland.
Studying the self-assembly of chiral molecules in two dimensions offers insights into the fundamentals of crystallization. Using scanning tunneling microscopy, we examine an uncommon aggregation of polyaromatic chiral molecules on a silver surface. Dense packing is achieved through a chiral triangular tiling of triads, with N and N ± 1 molecules at the edges.
View Article and Find Full Text PDFChem Phys Lipids
December 2024
Biochemistry and Molecular Biology Department, Faculty of Biology, Complutense University, Madrid, Spain; Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain.
Pulmonary surfactant is a membranous complex that enables breathing dynamics at the respiratory surface. Extremely low values of surface tension are achieved at end-expiration thanks to a unique mixture of lipids and proteins. In particular, the hydrophobic surfactant proteins, specially the protein SP-B, are crucial for surfactant biophysical function, in order to provide the surfactant lipid matrix with the ability to form membranous multi-layered interfacial films that sustain optimal mechanical properties.
View Article and Find Full Text PDFNanoscale
December 2024
Institute for Condensed Matter Physics, Technische Universität Darmstadt, Hochschulstrasse 8, 64289 Darmstadt, Germany.
Biological membranes predominantly consist of fluid lipid phases featuring lateral mobility and a considerable disorder of their hydrocarbon chains. Langmuir monolayers of lipids at the air/water interface are versatile model systems for fundamental physicochemical and biophysical membrane investigations. Grazing-incidence X-ray diffraction (GIXD) is a powerful tool for the structural characterization of such monolayers but has so far been used almost exclusively for lipid phases of crystalline ordering giving rise to sharp diffraction peaks.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Department of Applied Science, William & Mary, Williamsburg, Virginia 23185, United States.
Lysophospholipids (LPLs) and host defense peptides (HDPs) are naturally occurring membrane-active agents that disrupt key membrane properties, including the hydrocarbon thickness, intrinsic curvature, and molecular packing. Although the membrane activity of these agents has been widely examined separately, their combined effects are largely unexplored. Here, we use experimental and computational tools to investigate how lysophosphatidylcholine (LPC) and lysophosphatidylethanolamine (LPE), an LPL of lower positive spontaneous curvature, influence the membrane activity of piscidin 1 (P1), an α-helical HDP from fish.
View Article and Find Full Text PDFEur J Pharm Sci
December 2024
Departamento de Química e Bioquímica, Faculdade de Ciências, Centro de Química Estrutural, Institute of Molecular Sciences, Universidade de Lisboa, Campo Grande 1749-016, Portugal. Electronic address:
Tuberculosis is one of the leading causes of mortality worldwide due to the growth of multi-drug resistant strains unsusceptible to currently available therapies. Four compounds, isoniazid (INH) and three derivatives, N'-decanoylisonicotinohydrazide (INHC10), N'-(E)-(4-phenoxybenzylidene)isonicotinohydrazide (N34) and N'-(4-phenoxybenzyl)isonicotinohydrazide (N34red), were studied. Owing to their advantageous in vitro selectivity index against the primary mutation responsible for drug resistance in Mycobacterium tuberculosis (Mtb), as well as their suitable lipophilicity and interaction with human serum albumin, INHC10 and N34 were deemed promising antitubercular compounds.
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