Micro-scale Viscoelastic Characterization of Human Skin Tissues as a Biomarker for Melanoma

Abstract

Viscoelastic parameters of formalin-fixed paraffin-embedded (FFPE) human skin tissue samples have been investigated via nanoindentation in an ex vivo condition as feasible biomarkers for melanoma (a type of skin cancer) diagnosis to understand the mechanics of human skin tissues better, specifically on the effects of disease progression. For thin slices at 8 $\mu$ m thickness of 5 normal and 5 melanoma affected human skin tissue samples, a combined loading condition that consists of a linear pre-loading and a sinusoidal dynamic loading from 0.01 - 10 Hz in 6 steps has been applied to achieve three viscoelastic parameters, storage modulus, loss modulus, and loss factor in addition to Young’s modulus experimentally. The normal human skin tissues have shown higher Young’s moduli by 17.5 % and behaved like less viscous materials than the melanoma affected human skin tissues. The statistical analysis using the two-sample t-test for the experimental results have been also presented to evaluate the performance of the approach as a valid method of melanoma diagnosis. Since recognizing the disease progression at an early stage is one of the important clinical challenges, in this regard, understanding the mechanical behaviors of human skin tissues is expected to play a critical role in diagnosing abnormality on human skin tissues.