The non-linear electrical properties of human skin make it a generic memristor

• Published in: Scientific reports Vol. 8; no. 1; pp. 15806 - 9
• Main Authors: Pabst, Oliver, Martinsen, Ørjan G., Chua, Leon
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25.10.2018; Nature Publishing Group
• Subjects: 631/57; 639/166/985; 639/166/987; 639/766/930/12; Electrical properties; Humanities and Social Sciences; Hysteresis; multidisciplinary; Science; Science (multidisciplinary); Skin; Stratum corneum; Sweat; Tissues; Voltage; Generic Memristor; Biomedical Sensor Applications; Stimulus Voltage; Sweat Ducts; Pinched Hysteresis Loop
• DOI: 10.1038/s41598-018-34059-6
• ISSN: 2045-2322

An electrical measurement is non-linear when the applied stimulus itself affects the electrical properties of the underlying tissue. Corresponding voltage-current plots may exhibit pinched hysteresis loops which is the fingerprint of a memristor (memory resistor). Even though non-linear electrical properties have been demonstrated for different biological tissues like apples, plants and human skin, non-linear measurements as such have not been defined, yet. We are studying the non-linear properties of human skin systematically and initiate non-linear measurements on biological tissues as a field of research in general by introducing applicable recording techniques and parameterization. We found under which voltage stimulus conditions a measurement on human skin is non-linear and show that very low voltage amplitudes are already sufficient. The non-linear properties of human skin originate from the sweat ducts, as well as, from the surrounding tissue, the stratum corneum and we were able to classify the overall skin memristor as a generic memristor. Pinched hysteresis loops vary largely among subjects; an indication for the potential use in biomedical sensor applications.