A PDMS-based microneedle array electrode for long-term ECG recording.

Area of Science:

• Biomedical Engineering
• Materials Science
• Wearable Technology

Background:

• Traditional Ag/AgCl wet electrodes with conductive gel reduce short-term electrode-skin interface impedance (EII) for electrocardiogram (ECG) signal acquisition.
• The inflexibility and instability of wet electrodes limit their use in long-term monitoring for intelligent wearable devices.
• Dry electrodes offer a solution to the drying-out problem associated with conductive gels in wearable applications.

Purpose of the Study:

• To develop a flexible microneedle array electrode (FMAE) for reliable, long-term ECG monitoring.
• To evaluate the performance of FMAE compared to traditional electrodes in terms of impedance and signal quality.

Main Methods:

• Fabrication of a flexible microneedle array electrode (FMAE) using a polydimethylsiloxane (PDMS) substrate.
• The fabrication process involved silicon molding, dual PDMS shape-transferring, and encapsulation, ensuring low cost, repeatability, and biocompatibility.
• Performance evaluation through impedance testing and long-term ECG monitoring in resting and jogging states.

Main Results:

• FMAE demonstrated lower and more stable electrode-skin interface impedance (EII) compared to other tested electrodes.
• Long-term ECG tests confirmed that FMAE can acquire durable, stable, and reliable bioelectrical signals.
• The microneedle design effectively penetrates the stratum corneum (SC) to obtain high-quality signals.

Conclusions:

• The developed FMAE is a promising technology for long-term, high-quality ECG monitoring.
• FMAE overcomes the limitations of traditional wet electrodes, offering a flexible and stable alternative for wearable health devices.