Antifouling All-Polymeric Microneedle Array for Long-Term Wearable ECG Monitoring.

Area of Science:

• Biomedical Engineering
• Materials Science

Background:

• Cardiovascular disease monitoring requires reliable long-term electrocardiogram (ECG) signal acquisition.
• Conventional gel electrodes suffer from dehydration and motion artifacts, limiting continuous monitoring.
• There is a need for advanced electrode materials for stable, long-term ECG monitoring.

Purpose of the Study:

• To develop a biocompatible, all-polymeric microneedle electrode (MNE) for stable, long-term ECG monitoring.
• To enhance MNE performance through surface modifications for reduced impedance and biofouling.
• To evaluate the MNE's mechanical properties, skin compatibility, and long-term ECG signal quality.

Main Methods:

• Fabrication of an all-polymeric MNE.
• Surface functionalization with poly(3,4-ethylenedioxythiophene):tosylate (PEDOT:Tos) to decrease interfacial impedance.
• Coating with zwitterionic sulfobetaine methacrylate (SBMA) to resist protein and cellular adhesion.
• Mechanical testing and optical coherence tomography for skin insertion assessment.
• In-situ evaluation using a wireless wearable ECG system over 14 days.

Main Results:

• The SBMA-coated MNE achieved low interfacial impedance (0.63 kΩ∙cm² at 10 Hz).
• Significant reduction in nonspecific protein and bacterial adhesion (84.2% for E. coli, 98.6% for BSA).
• Demonstrated excellent mechanical strength for skin penetration without deformation.
• Maintained high-quality ECG signal acquisition over a 14-day period.
• Outperformed gel electrodes in dynamic movement conditions.

Conclusions:

• The developed SBMA-coated MNE offers a promising solution for stable, long-term ECG monitoring.
• This microneedle electrode technology overcomes limitations of conventional gel electrodes.
• The MNE enables reliable cardiovascular monitoring, especially in wearable and dynamic scenarios.