In vitro measurement of the mechanical properties of skin by nano/microindentation methods.

The elastic behaviors of stratum corneum, viable epidermis, dermis, and whole skin were investigated by nano/microindentation techniques. Insignificant differences in reduced elastic modulus of skin samples obtained from three different porcine breeds revealed breed type independent measurements. The reduced elastic modulus of stratum corneum is shown to be about three orders of magnitude higher than that of dermis. As a result, for relatively shallow and deep indentations, skin elasticity is controlled by that of stratum corneum and dermis, respectively. Skin deformation is interpreted in the context of a layered structure model consisting of a stiff and hard surface layer on a compliant and soft substrate, supported by microscopy observations and indentation measurements.