Piezoelectric Properties of Dry Human Skin

Mechanoelectrical conversion properties of dry human skin have been examined and their origin investigated in dermis, epidermis and horny layer. Shear stress piezoelectricity is observed in all three cutaneous sections. Piezoelectric properties of dermis can be ascribed to its collagen structural network, while the piezoelectric properties of epidermis appear to originate from partially oriented α-helical keratin-like tonofibrils. The highest piezoelectric coefficients have been found in horny layer samples. The values of thickness-compression piezoelectric coefficients were so low that they were not discernable from the intrinsic noise of the measuring system. Although thermally generated currents have been observed in the course of thermal pulse experiments, no evidence of relevant contributions from pyroelectric (polar) responses has been noticed in all cutaneous compartments.