title: In vivo confirmation of hydration-induced changes in human-skin thickness, roughness and interaction with the environment.
abstract: The skin properties, structure, and performance can be influenced by many internal and external factors, such as age, gender, lifestyle, skin diseases, and a hydration level that can vary in relation to the environment. The aim of this work was to demonstrate the multifaceted influence of water on human skin through a combination of in vivo confocal Raman spectroscopy and images of volar-forearm skin captured with the laser scanning confocal microscopy. By means of this pilot study, the authors have both qualitatively and quantitatively studied the influence of changing the depth-dependent hydration level of the stratum corneum (SC) on the real contact area, surface roughness, and the dimensions of the primary lines and presented a new method for characterizing the contact area for different states of the skin. The hydration level of the skin and the thickness of the SC increased significantly due to uptake of moisture derived from liquid water or, to a much lesser extent, from humidity present in the environment. Hydrated skin was smoother and exhibited higher real contact area values. The highest rates of water uptake were observed for the upper few micrometers of skin and for short exposure times.
authors.affiliation: Laboratory for Protection and Physiology, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-9014 St. Gallen, Switzerland and Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Agnieszka K
authors.initials: AK
authors.lastname: Dąbrowska
authors.affiliation: Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, ZHAW, CH-8820 Wädenswil, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Adlhart
authors.affiliation: Laboratory for Protection and Physiology, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-9014 St. Gallen, Switzerland.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Spano
authors.affiliation: Laboratory for Protection and Physiology, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-9014 St. Gallen, Switzerland and Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland.
authors.forename: Gelu-Marius
authors.initials: GM
authors.lastname: Rotaru
authors.affiliation: Laboratory for Protection and Physiology, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-9014 St. Gallen, Switzerland.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Derler
authors.affiliation: Laboratory for Protection and Physiology, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-9014 St. Gallen, Switzerland and Fashion Institute, Protective Clothing Research Center, Donghua University, 200051 Shanghai, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhai
authors.affiliation: Department of Materials, Laboratory for Surface Science and Technology, ETH Zürich, CH-8093 Zürich, Switzerland.
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Spencer
authors.affiliation: Laboratory for Protection and Physiology, Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-9014 St. Gallen, Switzerland.
authors.forename: René M
authors.initials: RM
authors.lastname: Rossi
mesh_terms: D005440:Fluid Therapy; D006801:Humans; D018613:Microscopy, Confocal; D012867:Skin / Q000033:anatomy & histology* / Q000737:chemistry*; D012879:Skin Physiological Phenomena; D013059:Spectrum Analysis, Raman; D013499:Surface Properties