Sponge Inspired Flexible, Antibacterial Aerogel Electrode with Long-Term High-Quality Electrophysiological Signal Recording for Human-Machine Interface

Flexible bioelectronics have a large range of applications in the field of human health monitoring and human-machine interfaces. Among various bioelectronics, flexible electrodes have been widely studied. However, it is still lack of investigation in the development of electrodes with high signal quality and long service life. Here, a sponge inspired flexible electrode based on cellulose aerogel is developed via thermally induced phase separation. Due to its flexibility, the electrode can easily conform to skin and achieve a higher signal-to-noise ratio (SNR) than the commercial rigid electrode. At the same time, the aerogel electrode with a sponge-like structure can absorb solutions several times their own weight (≈800%). In addition, the dope of polypyrrole coated silver nanowires (AgNWs@PPy) improves its intrinsic bactericidal activity (antibacterial rate above 97.8%) and the cellulose-based material itself offers good skin compatibility. Therefore, all these features contribute to a longer service life, while has been proven in electrophysiological signals recording. The SNR of electrocardiogram (ECG) signals recorded by aerogel electrode in 24 h is ≈15% higher than that of commercial electrode. Apart from that, when the commercial electrode is unavailable for eye-open (EO) and eye-closed (EC) paradigm in 12 h, the aerogel electrode can still record clear electroencephalogram (EEG) features.