A Low Contact Impedance Medical Flexible Electrode Based on a Pyramid Array Micro-Structure

Area of Science:

• Biomedical Engineering
• Materials Science
• Medical Device Technology

Background:

• Flexible electrodes are crucial for biosignal detection in medical diagnostics (ECG, EEG, EMG).
• High-quality signals are essential for accurate patient diagnosis and safety, directly impacted by electrode contact impedance.
• Existing flexible electrodes face challenges with maintaining low impedance for optimal performance.

Purpose of the Study:

• To develop a novel method for fabricating flexible electrodes with significantly reduced contact impedance.
• To enhance the contact area and bonding force between substrate and metal layers for improved electrode performance.
• To validate the effectiveness of the proposed fabrication technique for wearable and implantable medical applications.

Main Methods:

• Arraying pyramidal microstructures on polydimethylsiloxane (PDMS) substrates to increase electrode contact area.
• Coating a parylene transitional layer between PDMS substrates and metal membranes to improve bonding.
• Characterizing the contact area increase and measuring the contact impedance across a frequency range.

Main Results:

• The fabricated flexible electrodes demonstrated an 18.15% increase in contact area per unit area.
• Contact impedance ranged from 23 to 8 kΩ between 20 Hz and 1 kHz, outperforming commercial electrodes.
• The proposed method effectively reduced impedance and enhanced electrode performance.

Conclusions:

• The developed flexible electrodes exhibit excellent performance with low contact impedance and good biocompatibility.
• The fabrication method offers a promising approach for advancing flexible electrode technology in medical systems.
• This research provides a valuable reference for future developments in wearable and implantable biosensing devices.