Merkel cell-like artificial mechanoreceptor with high sensitivity and high resolution over a wide linear range

Abstract

Mammalian mechanoreceptors endow the skin with the ability to perceive mechanical stimuli with precision. However, the fabrication of artificial mechanoreceptors with high sensitivity and resolution over a wide linear pressure range remains a key challenge. Herein, an artificial ion mechanoreceptor with the core-shell structured nanofibrous membrane as the sensitive layer is proposed by mimicking the biomechanical receptor. The membrane embeds ionic liquids and poly(vinylidene fluoride-co-hexafluoropropylene) hybrid nanofibers into a thermoplastic polyurethane matrix, enabling a reversible conversion between non-ionic and iontronic sensing modes induced by tactilely triggered ion movements. It exhibits a high sensitivity (32.70 kPa −1 ), a linear response (R 2 ≈ 0.999) over a wide range of 0.04 Pa to 209 kPa, and an ultra-high resolution of 0.035% at 100 kPa (far exceeding the resolution of skin of ∼7%). The receptors are further used to monitoring physiological signals (even weak fingertip pulse signals) and assembled into an array to aid object recognition. • A core-shell structured ionic nanofiber membrane is constructed • The receptor can transform from non-ionic sensing to iontronic sensing under pressure • Good compatibility between high sensitivity and high linearity • High resolution even under high preload pressure By simulating the mechanotransduction mechanism of Merkel cells, Yang et al. fabricate an artificial mechanoreceptor that modulates ion migration under external pressure, which achieves both high sensitivity (32.701 kPa −1 ) and high linearity (R 2 = 0.999). In addition, it maintains 0.035% resolution at a high preload pressure of 100 kPa.