# Antifouling All‐Polymeric Microneedle Array for Long‐Term Wearable ECG Monitoring

## TL;DR

A new microneedle electrode is developed for long-term ECG monitoring, offering better performance and durability than traditional gel electrodes.

## Contribution

The development of a biocompatible, all-polymeric microneedle electrode with antifouling properties for stable long-term ECG monitoring.

## Key findings

- The MNEs have ultra-low interfacial impedance and resist protein and bacterial adhesion.
- The MNEs captured high-quality ECG signals for 14 days under dynamic movement.
- The MNEs outperformed gel electrodes in mechanical strength and signal stability.

## Abstract

Cardiovascular disease demands reliable long‐term monitoring for early and accurate diagnosis. While conventional gel electrodes are commonly utilized for monitoring electrocardiogram (ECG) signals, they have limitations, such as dehydration‐induced signal degradation and motion artifacts, hindering their effectiveness for continuous long‐term use. To address these issues, this study develops a biocompatible and all‐polymeric microneedle electrode (MNE) optimized for stable ECG monitoring over extended periods. The MNE surface is sequentially coated with poly(3,4‐ethylenedioxythiophene):tosylate (PEDOT:Tos) to reduce the interfacial impedance (0.63 kΩ∙cm2 at 10 Hz), followed by zwitterionic sulfobetaine methacrylate (SBMA) to prevent nonspecific protein adsorption and cellular adhesion (84.2% and 98.6% reduction in E. coli and BSA, respectively). Moreover, the SBMA‐coated MNE demonstrates excellent mechanical strength, allowing it to penetrate human skin without deformation, as verified by optical coherence tomography and insertion‐force assessments. In practical applications using a wireless wearable ECG monitoring system, the SBMA‐coated MNE consistently captures high‐quality ECG signals over a 14‐day period, significantly outperforming gel electrodes under dynamic movement conditions.

A biocompatible, all‐polymeric MNEs designed for long‐term ECG monitoring is developed. Coated with PEDOT:Tos and zwitterionic SBMA, the MNEs offer ultra‐low impedance and antifouling properties. After 14 days of continuous use, the MNEs accurately detected PQRST complexes, highlighting its potential for long‐term, real‐time ECG monitoring in everyday life.