Abstract
Human skin consists of the horny layer, living epidermis and dermis. Because their histology and constituents are different among the layers, the mechanical properties of each layer may also differ. However, there have been few studies on the difference among these layers. In this study, we measured the uniaxial tensile properties of the horny layer, epidermis and dermis of the guinea pigs. The tensile test was performed in the physiological saline solution at 37℃. With regard to the horny layer, the test was also performed in the air at room temperature with the humidity of about 75% and 15%. In the physiological saline solution, the elastic modulus of the horny layer was 180kPa, epidermis 130kPa, and dermis 80kPa. Based on these values and the thickness of each layer, the elastic modulus of living epidermis was estimated to be 70kPa. The elastic modulus of the horny layer depended strongly on the humidity, and was 720kPa at 70% and 10MPa at 15%. These results suggest that the mechanical properties of the skin are different among layers, and the horny layer is much stiffer than other two layers.
