The relative contributions of different skin layers to the mechanical behavior of human skin in vivo using suction experiments

Hendriks, F.M.; Brokken, D.; Oomens, C.W.J.; Bader, D.L.; Baaijens, F.P.T.

doi:10.1016/j.medengphy.2005.07.001

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Volume 28, Issue 3 , Pages 259-266, April 2006

The relative contributions of different skin layers to the mechanical behavior of human skin in vivo using suction experiments

F.M. Hendriks
- Eindhoven University of Technology, Department of Biomedical Engineering, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
D. Brokken
- Philips Research Laboratories, Personal Care Institute, Eindhoven, The Netherlands
C.W.J. Oomens
- Eindhoven University of Technology, Department of Biomedical Engineering, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Corresponding author. Tel.: +31 40 247 2818; fax: +31 40 244 7355.
D.L. Bader
- Eindhoven University of Technology, Department of Biomedical Engineering, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Queen Mary University of London, Department of Engineering and Interdisciplinary Research Centre in Biomedical Materials, London, UK
F.P.T. Baaijens
- Eindhoven University of Technology, Department of Biomedical Engineering, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

Received 10 January 2005; received in revised form 27 April 2005; accepted 7 July 2005. published online 12 August 2005.

Abstract

Although the mechanical behavior of the top layer of the skin, the epidermis, is an important consideration in several clinical and cosmetic applications, there are few reported studies on this layer. The in vivo mechanical behavior of the upper skin layer (here defined as epidermis and papillar dermis) was characterized using a combined experimental and modeling approach. The work was based on the hypothesis that experiments with different length scales represent the mechanical behavior of different skin layers. Suction measurements with aperture diameters of 1, 2 and 6mm were combined with ultrasound and optical coherence tomography to study the deformation of the skin layers. The experiments were simulated for small displacements with a two-layered finite element model representing the upper layer and the reticular dermis. An identification method compared the experimental and numerical results to identify the material parameters of the model. For one subject the whole parameter estimation procedure was completed, leading to a stiffness of C_10,ul=0.11kPa for the top-layer and C_10,rd=0.16MPa for the reticular dermis. This unexpected, extreme stiffness ratio of the material parameters let to convergence problems of the finite element software for most of the individuals.