MXene-Enabled Self-Adaptive Hydrogel Interface for Active Electroencephalogram Interactions

Abstract

Human–machine interaction plays a significant role in promoting convenience, production efficiency, and usage experience. Because of the universality and characteristics of electroencephalogram (EEG) signals, active EEG interaction is a promising and cutting-edge method for human–machine interaction. The seamless, skin-compliant, and motion-robust human–machine interface (HMI) for active EEG interaction has been in focus. Herein, we report a self-adaptive HMI (PAAS-MXene hydrogel) that can activate rapid gelation (5 s) using MXene cross-linking and conformably self-adapt to the scalp to help improve signal transduction. In addition to exhibiting satisfactory skin compliance, appropriate adhesion, and good biocompatibility, PAAS-MXene has demonstrated electrical performance reliability, such as low impedance (<50 Ω) at physiologically relevant frequencies, stable polarization potential (the rate of change is less than 6.5 × 10–4 V/min), negligible ion conductivity, and impedance change after 1000 stretch cycles, thereby realizing acquisition of EEG signals. In addition, a cap-free EEG signal acquisition method based on PAAS-MXene has been proposed. These findings confirm the high-precision detection ability of PAAS-MXene for electrocardiogram signals and EEG signals. Therefore, PAAS-MXene offers an option to actively control intention, motion, and vision through active EEG signals.

A Nanoclay-Enhanced Hydrogel for Self-Adhesive Wearable Electrophysiology Electrodes with High Sensitivity and Stability

“…As shown in Figure 4 a, the weight loss rate of NEH was bigger than that of HCEP at 40 °C, 10% humidity, and 65.4% of NEH remained after 24 h. Besides, 65.3% of NEH and 78.5% of HCEP remained at 20 °C, 20% humidity for 7 days ( Figure 4 b). As we all know, when water evaporates, the hydrogel cannot maintain the tight adhesion; which, results in instability at the skin–electrode interface to influence signal quality and stability [ 22 ]. In our experiments, although the weight of NEH decreased more quickly than that of HCEP, the results also exhibited a certain water retention performance of NEH owing to the added glycerin.…”

“…Sun [ 21 ] reported a copoly(acrylate-acrylic acid) hydrogel electrode with excellent water-resistant, underwater adhesion and swelling resistance for application to human skin in the aquatic environment. Luo [ 22 ] presented an MXene-poly(acrylic acid) composite hydrogel electrode which can provide excellent skin compliance. However, these hydrogel-based dry electrodes commonly have relatively unstable and low-sensitive biosignals, due to their electron conduction and subsequently high skin–electrode impedance.…”

Skin-Inspired Ultra-Tough Supramolecular Multifunctional Hydrogel Electronic Skin for Human–Machine Interaction

“…We further compared the advantages of our hydrogel with other research work in terms of GF and electrical conductivity, and the results showed the superior performance of PGC hydrogels (Fig. 3f) [26,43,47,49,61,[63][64][65][66][67][68][69][70][71]. In addition, we tested the response/recovery time (100/150 ms) of the hydrogel sensor during stretching and compared it with other reported work (Fig.…”

A review on accelerated development of skin-like MXene electrodes: from experimental to machine learning

“…Luo et al developed an MXene based sensor that can effectively sense brain electrical signals. 157 The data generated from these electrodes were processed using the Long Short-Term Recurrent Neural Network (RNN) model. The specialty of these models is that they retain the important information and discard the unimportant ones.…”