Wearable System Based on Ultra-Thin Parylene C Tattoo Electrodes for EEG Recording

Abstract

In an increasingly interconnected world, where electronic devices permeate every aspect of our lives, wearable systems aimed at monitoring physiological signals are rapidly taking over the sport and fitness domain, as well as biomedical fields such as rehabilitation and prosthetics. With the intent of providing a novel approach to the field, in this paper we discuss the development of a wearable system for the acquisition of EEG signals based on a portable, low-power custom PCB specifically designed to be used in combination with non-conventional ultra-conformable and imperceptible Parylene-C tattoo electrodes. The proposed system has been tested in a standard rest-state experiment, and its performance in terms of discrimination of two different states has been compared to that of a commercial wearable device for EEG signal acquisition (i.e., the Muse headset), showing comparable results. This first preliminary validation demonstrates the possibility of conveniently employing ultra-conformable tattoo-electrodes integrated portable systems for the unobtrusive acquisition of brain activity.

Advances in Electrode Materials for Scalp, Forehead, and Ear EEG: A Mini-Review

“…Temporary tattoos (Figure f) have been utilized for monitoring electrophysiological signals, as they provide conformal and imperceptible contact to the skin using van der Waals forces and permit the hair to grow through them. ,, Ferrari et al used inkjet-printed electrodes on 1.5-μm-thick commercial temporary tattoo paper using a poly­(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) aqueous dispersion and confirmed their electrical stability for up to 48 h (Figure c1,c2). They reported a skin–electrode impedance of around 17 × 10 3 kΩ•cm 2 and 1.3 × 10 3 kΩ•cm 2 at 10 Hz for their printed tattoo electrode and a commercial wet Ag/AgCl electrode, respectively.…”

“…Consumer forehead EEG devices (characteristics summarized in Table ) have been gaining popularity among the general public for various applications, such as meditation, entertainment, , and research. − The available information about the electrodes’ hardware is scarce since most of the work is proprietary. Other than BrainCo Focus 1, all listed electrodes are dry, mainly made of metals (the type of metal not specified).…”

Current On-Skin Flexible Sensors, Materials, Manufacturing Approaches, and Study Trends for Health Monitoring: A Review

“…86 Achieving this would mean that e-tattoos would be able to monitor biological signals directly through the epidermis, without being perceived during wear or causing foreign body sensation, while also opening the doors to advances in the areas of drug delivery systems, where the timely delivery of drugs across the dermis to a target area upon detection of a trigger would allow for optimized diagnosis and treatment of a wide range of conditions. 85,86 Other applications include electrodes in neuro-interfaces, recording electro-oculograms (EOG), 87 monitoring heart and brain activity through electrocardiograms (ECG) 88 and electroencephalograms (EEG), 89 among other biopotentials such as body temperature, all thanks to the inconspicuous nature of the e-tattoo. 90 Some manufacturing approaches aiming for breathable etattoos include phase separation, electrostatic spinning, and template-based methods, while others, such as spin-coating, are effective in producing ultrathin structures but lack the ability to achieve breathability, a challenge that, while persistent, will impact the ability to meet the ever-growing demand for these devices.…”

Recent Progress in Long-Term Sleep Monitoring Technology

“… Method for collecting electrical signals on the skin’s surface: ( a ) gold electronic tattoo [ 99 ]. Reproduced under the terms of the CC-BY Creative Commons Attribution License, Copyright 2023 by the authors, published by MDPI.…”