Pressure-Activated Breathable Liquid-Metal Electrodes for Long-Term Sleep Electroencephalogram Monitoring

Area of Science:

• Biomedical Engineering
• Materials Science

Background:

• Conventional gel electrodes for electroencephalography (EEG) monitoring face challenges like moisture loss and poor breathability.
• These limitations compromise long-term signal stability and user comfort during extended use.

Purpose of the Study:

• To develop breathable, biocompatible liquid-metal electrodes with improved interfaces for enhanced EEG monitoring.
• To address the drawbacks of traditional gel electrodes for wearable health applications.

Main Methods:

• Fabrication of liquid-metal electrodes using eutectic gallium-indium particles coordinated with (3-mercaptopropyl) triethoxysilane on a fiber matrix.
• Utilizing ambient drying to form a polymer network that encapsulates liquid-metal droplets within the fiber matrix.
• Demonstrating electrode functionality through pressure-induced liquid metal exusion for interface formation.

Main Results:

• The novel electrodes exhibit excellent tolerance to washing, air exposure, and mechanical stress.
• Demonstrated superior skin compatibility and lower interface impedance compared to commercial gel electrodes.
• Successfully achieved continuous 6-hour sleep electroencephalography monitoring using integrated head-worn epidermal electrodes.

Conclusions:

• The developed liquid-metal electrodes provide a promising alternative for unobtrusive and long-term wearable health surveillance.
• These electrodes enhance comfort and signal stability for applications like sleep monitoring.