Functionalized Adhesive Thin Flexible Electrode Arrays for Large-Scale Unobtrusive Ambulatory Monitoring of Neuromuscular Activity

Wearable electrical sensors offer noninvasive, high-fidelity monitoring of organ-level neuromuscular activity. In gastrointestinal applications, electrogastrography (EGG) enables detection of slow-wave (0.05 Hz) gastric myoelectric activity from the skin surface. However, commonly used current electrode systems with individually placed 3M Red Dot electrodes are bulky, prone to electrode placement variability, and unsuitable for long-term or unsupervised clinical use. Here, we present a comparative evaluation of scalable fabrication strategies for a conformable, adhesive-integrated electrode array designed specifically for continuous, high-resolution EGG (HR-EGG). The array is constructed on thin, flexible polyimide substrates with rounded perforations to improve breathability and is paired with a gentle, silicone-based medical adhesive suitable for sensitive skin. This design enables consistent inter-electrode spacing, reduces user burden, and offers significant conformability improvements over rigid commercial multi-electrode systems. It also offers scalability advantages over soft stretchable arrays requiring cleanroom fabrication. Multiple electrode interface strategies-including Ag/AgCl, dry PEDOT:PSS, and conductive hydrogel coatings-are implemented and characterized using electrical impedance spectroscopy. The final patch design is validated through a representative pre- and post-meal recording, showing reliable capture of gastric slow-wave activity. This work supports scalable deployment of HR-EGG in clinical and research settings, expanding access to noninvasive gastrointestinal diagnostics.