Peter Sjövall oral presentation (OB3-Tue4-2-2)
Spatial distribution of molecular components in human skin cross sections determined by ToF-SIMS and SEM.
1 RISE Research Institutes of Sweden, Brinellgatan 4, 50115 Borås, Sweden
2 RISE Research Institutes of Sweden, Drottning Kristinas väg 4, 11486 Stockholm, Sweden
3 L'Oréal Research and Innovation, 1 Avenue Eugène Schueller, 93600 Aulnay-sous-Bois, France
4 L'Oréal Research and Innovation, 188 Rue Paul Hochart, 94550 Chevilly-Larue, France
The major functions of skin, such as a barrier against water loss, microbial invasion and penetration of xenobiotics rely, in part, on the spatial distribution of the biomolecular constituents that make up the skin structure, particularly its horny layer (the stratum corneum). However; all skin layers are of importance to describe dysfunctional skin conditions, and to develop adapted therapies or skin care products. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to image the spatial distribution of a variety of molecular species, from stratum corneum down to dermis, in 10-20 µm thick cross-section slices of human abdominal skin, prepared by cryosectioning. Scanning electron microscopy (SEM) was conducted to relate the molecular distributions to morphological structures in the skin. The results showed strong localization of cholesterol sulfate, ceramide and saturated long-chain fatty acids to stratum corneum/epidermis, consistent with the documented lipid composition of stratum corneum , whereas phospholipids and protein fragments were evenly distributed throughout the entire skin cross section. Triglycerides were primarily localized to specific structures in the skin cross section corresponding to remaining sebum at the skin surface, sebaceous glands and residual adipocytes from hypodermis as full thickness human skin was used. Furthermore, the possibility to localize exogenous compounds is demonstrated by the detection and imaging of carvacrol (a constituent of oregano or thyme essential oil), after topical application of an aqueous gel containing this compound. Carvacrol showed pronounced accumulations to some of the triglyceride-containing observed structures. We show as well the complementary character of this approach with well-established cutaneous absorption quantification studies.
 J.A. Bouwstra and M. Ponec, The skin barrier in healthy and diseased state, Biochim. Biophys. Acta 1758 (2006) 2080-2095