Self-Powered, Stretchable, and Wearable Ion Gel Mechanoreceptor Sensors

Abstract

Mechanoreceptors in human skin are important and efficient cutaneous sensors that are highly sensitive, selective, and adaptive to the environment. Among these, Merkel disk (MD) and cilia are capable of sensing an external mechanical force through a receptor with a sharp pillar-like structure at its end. Then, the signal of the action potential is generated by pumping Na+ ions through ion channels. In this study, a self-powered, stretchable, and wearable gel mechanoreceptor sensor is developed inspired by the structural features of the MD and cilia with sharp tips and the signaling characteristics of mechanoreceptor ion migration. Poly(vinylidene fluoride-co-trifluoroethylene) gel is used to implement a self-powered system, and polyvinylchloride-based elastic gel is utilized to detect sensing signals based on charge transfer and distribution. The surface of all gels is that of a conical structure to achieve high sensor sensitivity and conformal contact with a target surface. In addition, using the developed sensors, various biological signals related to pressure/strain occurring in the human body (e.g., blood pressure (BP), muscle movement, and motion) are acquired. Furthermore, the behavior of arterial BP was investigated during the contraction and relaxation of the muscles.