Imaging of the human Glisson's capsule by two-photon excitation microscopy and mechanical characterisation by uniaxial tensile tests

38ième congrès de la Société de Biomécanique francophone, MARSEILLE, FRANCE, 06-/09/2013 - 09/09/2013Mechanical properties of the liver have been well investigated through many studies at the macroscopic level. These studies allowed elaborating more or less sophisticated models providing material data. The rupture phenomenon has been studied as well, for example by Brunon et al. (2011) to collect data on how the liver, and more precisely the Glisson's capsule, responds to mechanical loading. With the emergence of multimodal microscopy, these phenomena have been considered to a whole different scale, as we can now investigate the behaviour of these materials at the microscopic level. This way, we can have a better understanding of damage and rupture mechanisms of these tissues, linking them to microstructure organisation and thus developing realistic models based on microstructure. Recent studies have therefore focused on imaging the microstructure organisation of biological materials during or after loading. For example, Goulam Houssen et al. (2011) have monitored the behaviour of the rat-tail collagen fibres during uniaxial loading using second harmonic generation (SHG) from two-photon excitation (TPE) microscopy. Keyes et al. (2013) used SHG and autofluorescence from TPE to image pressurised porcine coronary arteries and observed realignment of the fibres. Thus, the aim of this study was to observe how the different constitutive fibres of the Glisson's capsule are organised and how they react when subjected to uniaxial tensile loading, in order to understand how microstructural organisation impacts macro-mechanical properties. In the first step, we worked on the imaging of the Glisson's capsule by TPE to enforce our knowledge of its components and their state before loading. In the second step, we carried out preliminary tensile tests using an in situ micro-tensile stage to estimate mechanical parameters such as apparent modulus, ultimate stress and ultimate strain