Full-field bulge test for planar anisotropic tissues: Part I – Experimental methods applied to human skin tissue

A mechanistic insight into the mechanical role of the stratum corneum during stretching and compression of the skin

“…This is currently very challenging but there are very promising emerging approaches in skin research. For example, using digital image correlation techniques it is possible to obtain full (strain) field measurements (Tonge et al, 2013a;Tonge et al, 2013b). The modelling approach adopted here is a first step towards models to assess, understand and control the effects of the structural properties of skin in medicine, biology and industrial applications.…”

“…In a finite element modelling context, it implies that using a single set of mechanical properties for the stratum corneum would limit the domain of validity of the simulation results to specific conditions. A wide array of experimental and clinical measurement techniques are used to characterise particular aspects of skin biology and biophysics (Alexiades-Armenakas, 2007;Batisse et al, 2002;Bellemere et al, 2009;Delalleau et al, 2006;Diridollou et al, 2000;Gunner et al, 1979;Hendriks et al, 2006;Jor et al, 2013;Limbert and Simms, 2013;Tonge et al, 2013a;Tonge et al, 2013b;Wan Abas, 1994). Nevertheless, complementary approaches based on mathematical and computational modelling techniques offer promising avenues to further our understanding of the skin (Areias et al, 2003;Bischoff et al, 2000;Boissieux et al, 2000;Buganza Tepole and Kuhl, 2014;Cavicchi et al, 2009;Duan et al, 2000;Evans, 2009;Flynn and McCormack, 2008a, b;Flynn andMcCormack, 2009, 2010;Hendriks et al, 2006;Hendriks et al, 2003;Kuwazuru et al, 2008;Larrabee and Galt, 1986a, b;Larrabee and Sutton, 1986;Lévêque and Audoly, 2013;Tepole et al, 2014a;Tepole et al, 2014b;Tepole et al, 2011;Zöllner et al, 2013).…”

Nondestructive mechanical characterization of developing biological tissues using inflation testing

“…These equations were initially derived for thin axisymmetric geometries [10,11], however it has been demonstrated that they can closely approximate the stress resultants in geometries that do not necessarily deform axisymmetrically due to material anisotropy [35,36] including anisotropic tissues subjected to inflation testing [19,20,37].…”

“…US imaging is key to this setup, as it allows for measurements of the tissue deformation during bulge testing, a test that can now be performed inside the bioreactor. Previous studies have typically measured the tissue deformation during bulging using stereo camera setups [19,21,22,23,37,39] or advanced optical rigs [18,40], which are incompatible with the limited view of samples insides a bioreactor. In contrast, US is able to measure throughout the tissue cross-section, and can therefore be easily mounted on top of a bioreactor.…”

“…Finally, biological planar tissues are not always thin enough to be considered as membranes, leading to bending moments and out-of-plane stresses. Several studies have successfully incorporated tissue nonlinearity and anisotropy in parameter estimation schemes of bulge tests [18,19,20,21,22,23]. Yet, no study has, to the best of the authors' knowledge, addressed the effects of tissue thickness, nor has tissue prestretch been accounted for.…”