An On-Skin Electrode with Anti-Epidermal-Surface-Lipid Function Based on a Zwitterionic Polymer Brush

Area of Science:

• Biomedical Engineering
• Materials Science
• Wearable Technology

Background:

• On-skin flexible devices enable continuous biological signal acquisition for chronic disease diagnosis and smart health monitoring.
• Existing flexible devices face challenges with mechanical mismatch and susceptibility to skin lipids, limiting long-term use.
• Epidermal surface lipids (skin oil) degrade the performance and reusability of conventional on-skin electronics.

Purpose of the Study:

• To develop an on-skin electrode with resistance to epidermal surface lipids for improved long-term usability.
• To create a reusable on-skin electronic device that can be easily cleaned.
• To demonstrate the efficacy of the novel electrode for biological signal recording.

Main Methods:

• Grafting a zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) brush onto gold-coated poly(dimethylsiloxane) (Au/PDMS) substrates.
• Utilizing the superhydrophilic nature of PMPC for facile cleaning of lipid-fouled surfaces with water.
• Employing the developed PMPC-Au/PDMS electrodes for electrocardiography (ECG) and electromyography (EMG) signal recording.

Main Results:

• The PMPC-grafted electrodes demonstrated resistance to epidermal lipids, allowing for simple water rinsing to restore functionality.
• Stable skin-electrode impedance and a good signal-to-noise ratio (SNR) were maintained after water rinsing.
• The electrodes proved effective for both ECG and EMG recordings, showcasing their practical application.

Conclusions:

• A novel on-skin electrode material was developed with anti-epidermal-surface-lipid properties.
• The PMPC-Au/PDMS electrode offers a material-based solution for enhanced long-term reusability of on-skin electronics.
• This advancement provides a pathway for next-generation wearable healthcare devices with improved durability and user convenience.