Robust skin-integrated conductive biogel for high-fidelity detection under mechanical stress

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Soft conductive gels are crucial for epidermal electronics but struggle with integration on uneven or hairy skin, especially under mechanical stress.
• Existing materials often lack the necessary mechanical robustness and adhesion for reliable biointerfacing.

Purpose of the Study:

• To design an in-situ biogel capable of liquid-to-solid transformation for enhanced biointerfacing.
• To improve the mechanical properties, adhesion, and signal acquisition capabilities of conductive gels for epidermal electronics.

Main Methods:

• Utilized a liquid-to-solid transformation strategy triggered by a temperature switch within 3 minutes.
• Engineered a semi-interpenetrating polymer network with dual conduction pathways.
• Characterized tensile strength, skin-compatible modulus, skin adhesive strength, and signal-to-noise ratio (SNR).

Main Results:

• Achieved high tensile strength (~1-3 MPa) and a skin-compatible modulus (~0.3-1.1 MPa).
• Demonstrated strong skin adhesive strength (~1 MPa) and superior signal-to-noise ratio (SNR, ~30-40 dB).
• Successfully captured outdoor exercise data and monitored physiological signals in mechanically demanding environments.

Conclusions:

• The developed biogel's liquid-to-solid transformation enhances integration at biointerfaces, overcoming challenges with uneven and hairy skin.
• The material's robust mechanical properties and high signal fidelity support applications in wearable electronics for monitoring physical activity and physiological signals.
• This design strategy advances conductive interface materials for high-fidelity signal acquisition in demanding conditions.