On mechanoelectrical transduction phenomena of human skin: Piezoelectric properties in the dry state

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 the three cutaneous compartments. 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. Highest piezoelectric coefficients have been found in horny layer samples. Although thermally generated currents have been observed in the course of thermal pulse experiment, no evidence of relevant contribution from pyroelectric (polar) response has been noticed.