The Influence of Multiscale Collagen Mechanics on Skin Wrinkling

Collagen is a key structural component of many biological tissues including human skin. Dermis layer of skin, which consists of a crosslinked network of collagen and elastin fibers, gives skin the mechanical integrity. Collagen fibers are made up of structural components namely, fibrils and tropocollagen molecules, at lower length-scales. The properties of these components determine the mechanical properties of collagen fibers, and that of the entire skin. Any alteration to the properties of the microscopic constituents can have a huge effect on the overall physiological response of skin. Therefore a multiscale modelling framework can efficiently capture this complex mechanics of collagen fibers in human skin. In this work, we use multiscale mechanics and finite element modelling to characterize the influence of collagen mechanics on the macroscopic response of human skin. Using this framework we investigate the influence of various collagen properties on the wrinkling behavior of human skin. Using FEM simulations, we show that collagen properties such as fiber orientation, dispersion and aspect ratio have a significant influence on the macroscopic wrinkle size. Our results on the influence of collagen dispersion on the wrinkle height correlate with the experimentally reported trends on ageing-induced skin wrinkling. To the best of authors’ knowledge, this is the first 3D multiscale FEM model that considers the influence of collagen anisotropy on skin wrinkling. This study can be very useful in developing pharma and cosmetic products for skin-care and anti-aging applications.