Investigation of the biomechanical properties of goat skin

Abstract

Background: Skin is the largest organ by surface area in almost all of the animal species. Since it positions as an interface between internal body and external environment, it is specialized to undergo various functions like secretion, protection and absorption. In this study we investigated the mechanical properties of goat skin. Methods: Goat skin (n=7) were obtained from local slaughterhouse. Two rectangular samples perpendicular to each other were obtained from each specimen. Uniaxial tensile experiments were performed at 5 mm/sec, 10 mm/sec and 20mm/sec. The experimental output data -load and extension- from the uniaxial testing instrument was used to calculate Cauchy stress and stretch. Then nonlinear regression analysis was done to find the best hyperelastic model that fits with least error. Scanning electron microscope and histology analysis were also performed to obtain structural data. Analysis: The goat skin exhibited non-linear stress strain response with stiffer response in the vertical direction compared to horizontal direction under all strain rates. The resulting mechanical response is due to the recruitment and alignment of collagen fibres in the direction of deformation. The experimental data fitted with Ogden model with coefficient of determination in the range of 0.97-0.99.

Result and Conclusion: Skin is a multilayered structure that can withstand large deformations and analysing the biomechanical properties are important to understanding the fields like impact study, skin injury, tissue engineering, pathology. The goal of this work is to form a basis for the possibility of goat skin as a material for tissue engineering grafts by understanding its mechanical properties and microstructure. All samples exhibited non-linear and anisotropic behavior with samples excised along long axis stiffer than the samples excised perpendicular to the long axis. The scanning electron microscope and histology image clearly identified the distribution of collagen fibers. The model parameters obtained can be combined with finite element modelling and simulation for studying skin behaviour during mechanical impact, damage and treatment.