A Bioinspired, Durable, and Nondisposable Transparent Graphene Skin Electrode for Electrophysiological Signal Detection

Abstract

Graphene, with its properties of intrinsic flexibility, reliable electrical performance, and high chemical stability, is highly desirable as bioelectrodes for detecting electrophysiological signals. However, its mechanical properties limit its application to a great extentenergy dissipation mechanisms are not provided by the carbon network for external strain and it easily cracks. Herein, inspired by the very structure of the avian nest, we report a durable and nondisposable transparent graphene skin electrode for detecting electrophysiological signals, which was fabricated by semi-embedding highly graphitized electrospun fiber/monolayer graphene (GFG) into soft elastomer. Because of the semi-embedded structure and strong interaction between annealed electrospun fiber and graphene through graphitization, as-fabricated conductive film demonstrated high conductivity and transparency (∼150 Ω/□ at 83% transmittance), as well as a stable electrical performance under mechanical vibrations (strain, peel-off, stir, etc.). It can be used to reliably collect vital biometric signals, such as electrocardiogram (ECG), surface electromyogram (sEMG), and electroencephalogram (EEG). Furthermore, the semi-embedded GFG in the elastomer demonstrated excellent washability (rinsing/stirring in water) and repeatability (∼10 repeats) with high signal-to-noise ratio (up to 30 dB) while detecting sEMG. This is the first report of durable and transparent graphene skin electrode for biometric signals detection, revealing potential opportunities in wearable healthcare applications.

Ultra-conformal skin electrodes with synergistically enhanced conductivity for long-time and low-motion artifact epidermal electrophysiology

“…As the thinnest electrode material, graphene demonstrates superior optical transparency, high electrical conductivity, excellent mechanical property, and low electrochemical reactivity 21 – 32 (Supplementary Table 2 ). It is also regarded as a promising skin-electrode for electrophysiological signal detection 8 .…”

Preparation and Applications of Electrospun Optically Transparent Fibrous Membrane

“…Shin [ 93 ] et al fabricated moiré-fringeless TCFs with good optoelectrical characteristics and excellent thermal stability using a single-pass printed random serpentine network of medium-field electrospun silver microfibers (AgMFs), which would be used as flexible electronic devices. A transparent graphene skin electrode was also fabricated by annealing after electrospinning [ 94 ]. The precursor was prepared by dissolving styrene ethylene butylene styrene (SEBS), CuCl 2 , and phenolic resin (PR) into tetrahydrofuran (THF) solvent.…”

“…As a wearable resistance sensor, SNME was used to monitor the movement of finger joints. Qiu et al [ 94 ] obtained highly graphitized phenolic resin electrospun fibers/single-layer graphene (GFG) fibrous membrane by electrospinning, annealing, and solvent evaporation. It had high electrical conductivity and 83% high light transmittance and could be used as a wearable medical sensor for effective skin surface monitoring of biological signals.…”

High-Adhesive Flexible Electrodes and Their Manufacture: A Review

“…The geometric engineering fabrication method does not change the characteristics the material itself, but only the geometric pattern design of rigid materials to obtain p ticular tensile properties [35]. Generally speaking, conventional conductive rigid mate Reproduced with permission from [26]. Copyright 2020, American Chemical Society.…”

“…Using the conductive thread approach, no additional step is required to establish conductivity after manufacturing the fabric [87]. Qiu et al reported a transparent graphene skin electrode inspired by the structure of an avian nest [26]. Phenolic resin (PR) was first fixed to a graphene film by electrospinning technology and then the two were more closely adhered by annealing technology.…”