A Photocurable Conductive Hydrogel for Force Sensing of Cross-Type Muscle Tissue

Area of Science:

• Materials Science
• Biomedical Engineering
• Soft Robotics

Background:

• Monitoring muscle mechanical activity is vital for assessing myocardial function, human-machine interaction, and flexible electronics.
• Achieving mechanically compliant sensing with stable coupling to soft biological tissues presents significant challenges.

Purpose of the Study:

• To develop a mechanically tunable and photocurable conductive hydrogel with tissue-matched properties.
• To enable high-resolution fabrication and monolithic integration of sensing and encapsulation layers.
• To demonstrate the hydrogel's utility in biomechanical sensing applications.

Main Methods:

• Fabrication of a conductive hydrogel composite (PAAm/PEGDA/LAP/AgNWs) with a double-network structure.
• Tuning material properties (Young's modulus, stretchability) by adjusting AgNWs content.
• Utilizing digital light processing (DLP) 3D printing for high-resolution fabrication.

Main Results:

• The hydrogel achieved a Young's modulus of 162 ± 9 kPa, matching muscle tissue, with ultrahigh stretchability (>1200%).
• Stable electrical sensing capabilities were demonstrated under physiological deformation.
• Successful proof-of-concept devices showed muscle sensing and force detection, including monitoring myocardial tissue contractile forces (15-30 μN) and wearable facial muscle tension sensing (1-5 mN).

Conclusions:

• A scalable conductive hydrogel sensing platform was developed, integrating tissue-matched mechanics, advanced manufacturability, and broad biomechanical sensing capabilities.
• The photocurable and 3D-printable nature overcomes limitations of previous conductive hydrogels.
• The platform holds significant potential for advancing biomechanical research and human-machine interaction.