Stick-and-play bioadhesive hairlike electrodes for chronic EEG recording on human

Chronic high-fidelity electroencephalogram (EEG) recording faces challenges due to weak EEG signals and presence of hair, which create interfacial gaps and motion artifacts. To ensure reliable EEG recording, stable connection between electrodes and the scalp is essential. Metallic electrodes with electrolyte gel are commonly used, but their stability is often affected by gel drying and inconsistent electrode positioning across sessions. Here, we report stick-and-play hairlike device that can attach to the human scalp without the need for skin preparation, using a highly flexible and stretchable electrode material and robust bioadhesive material. The hairlike device can be worn for long term without being noticeable, maintaining a stable skin adhesion and interface impedance across different recording sessions and hundred cycles of cyclic loading. The design, which mimics human hair, makes it indistinguishable from a natural look. Additionally, the hairlike device has been demonstrated as an efficient medium for long-term, high-quality EEG recordings.