Merkel receptor-inspired integratable and biocompatible pressure sensor with linear and ultrahigh sensitive response for versatile applications

Abstract

Integrating high sensitivity with broad linear range for pressure sensors enables accurate data acquisition and avoids additional complex signal processing, bringing e-skins great liberation especially for high-precision applications such as medical diagnostic, bio-signal monitoring and human–machine interaction. However, it still remains a critical challenge to ease the conflicts between high sensitivity and high linearity via traditional micro-engineered strategies. Here, inspired by the sensing principle of Merkel receptors underlying epidermis, we propose a strategy of orthogonal knitted threads-induced local stress concentration that can significantly broaden the linear range of the pressure sensors without sacrificing the ultrahigh sensitivity. The high-modulus Ag/nylon threads orthogonally knitted onto low-modulus micro-structured non-woven fabrics generate enhanced local stress concentration at the intersections and facilitate the amplification and transfer of the pressure signals, achieving simultaneous enhancement of sensitivity (8.59 kPa−1) and linearity (0.2–400 kPa). With its miniaturable, integratable and biocompatible characteristics, as proof-of-concept demonstration, the sensors have been exploited for handwriting recognition, human–machine interaction and cardiovascular assessment.