Title
A new water absorbable mechanical Epidermal skin equivalent: The combination of hydrophobic PDMS and hydrophilic PVA hydrogel
Author
Morales-Hurtado, M.
Zeng, X.
Gonzalez-Rodriguez, P.
ten Elshof, J.E.
van der Heide, E.
Publication year
2015
Abstract
Research on human skin interactions with healthcare and lifestyle products is a topic continuously attracting scientific studies over the past years. It is possible to evaluate skin mechanical properties based on human or animal experimentation, yet in addition to possible ethical issues, these samples are hard to obtain, expensive and give rise to highly variable results. Therefore, the design of a skin equivalent is essential. This paper describes the design and characterization of a new Epidermal Skin Equivalent (ESE). The material resembles the properties of epidermis and is a first approach to mimic the mechanical properties of the human skin structure, variable with the length scale. The ESE is based on a mixture of Polydimethyl Siloxane (PDMS) and Polyvinyl Alcohol (PVA) hydrogel cross-linked with Glutaraldehyde (GA). It was chemically characterized by XPS and FTIR measurements and its cross section was observed by macroscopy and cryoSEM. Confocal Microscope analysis on the surface of the ESE showed an arithmetic roughness (Ra) between 14-16 μm and contact angle (CA) values between 50-60°, both of which are close to the values of in vivo human skins reported in the literature. The Equilibrium Water Content (ECW) was around 33.8% and Thermo Gravimetric Analysis (TGA) confirmed the composition of the ESE samples. Moreover, the mechanical performance was determined by indentation tests and Dynamo Thermo Mechanical Analysis (DTMA) shear measurements. The indentation results were in good agreement with that of the target epidermis reported in the literature with an elastic modulus between 0.1-1.5 MPa and it showed dependency on the water content. According to the DTMA measurements, the ESE exhibits a viscoelastic behavior, with a shear modulus between 1-2.5MPa variable with temperature, frequency and the hydration of the samples. Copyright © 2015 Elsevier Ltd. All rights reserved. Chemicals/CAS: dimeticone, 32028-95-8, 68248-27-1, 9004-73-3, 9006-65-9; polyvinyl alcohol, 37380-95-3, 9002-89-5; water, 7732-18-5; baysilon; Dimethylpolysiloxanes; Polyvinyl Alcohol; polyvinyl alcohol hydrogel; Water
Subject
Elastic modulus
Hydration
Polydimethyl Siloxane
Polyvinyl Alcohol hydrogel
Skin equivalent
Skin tribology
Young modulus
Absorption, Physicochemical
Biomimetic Materials
Dimethylpolysiloxanes
Elastic Modulus
Epidermis
Humans
Hydrophobic and Hydrophilic Interactions
Polyvinyl Alcohol
Surface Properties
Viscosity
Water
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DOI
https://doi.org/10.1016/j.jmbbm.2015.02.014
TNO identifier
531066
ISSN
1878-0180
Source
Journal of the mechanical behavior of biomedical materials, 46, 305-317
Document type
article