Article

Annals of Biomedical Engineering

, Volume 40, Issue 8, pp 1666-1678

First online:

Automated Estimation of Collagen Fibre Dispersion in the Dermis and its Contribution to the Anisotropic Behaviour of Skin

  • Aisling Ní AnnaidhAffiliated withSchool of Mechanical and Materials Engineering, University College DublinUPMC, Univ Paris 6, UMR 7190, Institut Jean Le Rond d’AlembertCNRS, UMR 7190, Institut Jean Le Rond d’Alembert Email author 
  • , Karine BruyèreAffiliated withUniversité de LyonIFSTTAR, LBMC, UMR_T9406Université Lyon 1
  • , Michel DestradeAffiliated withSchool of Mechanical and Materials Engineering, University College DublinSchool of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway
  • , Michael D. GilchristAffiliated withSchool of Mechanical and Materials Engineering, University College Dublin
  • , Corrado MauriniAffiliated withUPMC, Univ Paris 6, UMR 7190, Institut Jean Le Rond d’AlembertCNRS, UMR 7190, Institut Jean Le Rond d’Alembert
  • , Melanie OtténioAffiliated withUniversité de LyonIFSTTAR, LBMC, UMR_T9406Université Lyon 1
  • , Giuseppe SaccomandiAffiliated withDipartimento di Ingegneria Industriale, Università degli Studi di Perugia

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Abstract

Collagen fibres play an important role in the mechanical behaviour of many soft tissues. Modelling of such tissues now often incorporates a collagen fibre distribution. However, the availability of accurate structural data has so far lagged behind the progress of anisotropic constitutive modelling. Here, an automated process is developed to identify the orientation of collagen fibres using inexpensive and relatively simple techniques. The method uses established histological techniques and an algorithm implemented in the MATLAB image processing toolbox. It takes an average of 15 s to evaluate one image, compared to several hours if assessed visually. The technique was applied to histological sections of human skin with different Langer line orientations and a definite correlation between the orientation of Langer lines and the preferred orientation of collagen fibres in the dermis \((p<0.001, R^{2}= 0.95)\) was observed. The structural parameters of the Gasser–Ogden–Holzapfel (GOH) model were all successfully evaluated. The mean dispersion factor for the dermis was \(\kappa = 0.1404 \pm 0.0028.\) The constitutive parameters μ, k 1 and k 2 were evaluated through physically-based, least squares curve-fitting of experimental test data. The values found for μ, k 1 and k 2 were 0.2014 MPa, 243.6 and 0.1327, respectively. Finally, the above model was implemented in ABAQUS/Standard and a finite element (FE) computation was performed of uniaxial extension tests on human skin. It is expected that the results of this study will assist those wishing to model skin, and that the algorithm described will be of benefit to those who wish to evaluate the collagen dispersion of other soft tissues.

Keywords

Fibre orientation Anisotropic Skin Collagen Fibres