Metalon® JS-A191 Silver Nanoparticle Ink Powers Next-Generation Wearable sEMG Electrodes
Wearable health monitoring and human-machine interaction are rapidly advancing, with surface electromyography (sEMG) playing a pivotal role in capturing physiological signals. However, the reliability of sEMG systems, especially during prolonged non-active states, is often challenged by baseline noise. This noise can significantly impact signal stability and the accuracy of downstream data analysis, leading to false activations and unreliable detection thresholds. Addressing this critical challenge, a recent study published in the 2026 IEEE International Conference on Electro Information Technology (eIT) by Nabonita Mitra and Bashir I. Morshed from Texas Tech University presents a comparative analysis of baseline noise characteristics in inkjet-printed (IJP) Ag-nanoparticle dry sEMG electrodes against conventional gel electrodes.
Their work highlights the crucial role of advanced conductive inks in enabling high-performance, flexible biosensors. Specifically, the research demonstrates how NovaCentrix’s Metalon® JS-A191 silver nanoparticle ink contributed to the fabrication of dry sEMG electrodes that exhibit baseline noise characteristics comparable to traditional gel electrodes, while offering the inherent advantages of printed electronics for long-term wearable applications.
Why Stable Baseline Noise Matters for Wearable sEMG
Conventional gel electrodes, while effective for short-term EMG acquisition due to their low impedance, present several drawbacks for extended wearable use. These include potential issues with motion artifacts, powerline interference, and impedance variations over time, all of which can elevate baseline noise and degrade signal stability. Such limitations are particularly problematic for long-term wearable systems, where non-active states constitute a significant portion of operation, making reliable baseline noise management paramount.
Flexible inkjet-printed electrodes offer a compelling alternative. Their ability to be fabricated on flexible substrates allows for conformal contact with the skin, which can reduce motion-induced artifacts and enhance user comfort for prolonged wear. Beyond simply amplifying muscle activity signals, the design of these electrodes can actively improve wearable EMG performance by stabilizing the baseline and suppressing unwanted noise components, including low-frequency artifacts and powerline interference. This shift from traditional, bulky electrodes to flexible, printed solutions is essential for the next generation of truly reliable and comfortable wearable health devices.
The Role of NovaCentrix Metalon® JS-A191 Silver Nanoparticle Ink
The foundation of these advanced inkjet-printed sEMG electrodes lies in the selection of a high-performance conductive ink. For this study, researchers utilized NovaCentrix’s Metalon® JS-A191 silver nanoparticle ink. This commercial ink, manufactured by NovaCentrix, is specifically formulated for inkjet printing applications, making it an ideal choice for creating precise and reproducible electrode patterns on flexible substrates.
The electrodes were fabricated on flexible polyamide films using a PC-controlled Dimatix Materials Printer (DMP-2850). After printing, the ink was cured at 180°C for 20 minutes. The researchers’ choice of Metalon® JS-A191 was driven by its “highly conductive properties and compatibility with polyamide,” which are critical for achieving stable and reliable electrical performance in a flexible, wearable form factor.
Comparable Performance and Enhanced Reliability
The study meticulously evaluated the performance of the inkjet-printed electrodes by comparing their baseline noise characteristics to those of conventional gel electrodes across a complex EMG task protocol. This protocol included various states such as rest, graded muscle contractions, transition phases, and dynamic movements. Instead of solely focusing on peak signal amplitude, the researchers assessed baseline behavior using key signal-quality metrics during rest periods.
The results demonstrated that the IJP electrodes exhibited baseline noise characteristics remarkably comparable to conventional gel electrodes. This included similar root-mean-square amplitude during rest (RMSrelax), low-frequency artifact ratio (LFAR), and hum ratio. These findings are crucial as they indicate that the IJP electrodes can maintain signal stability while effectively controlling low-frequency motion artifacts and powerline interference. Furthermore, the IJP electrodes achieved consistently good signal-to-noise ratio (SNR) with smoother temporal evolution, even during dynamic tasks, underscoring their suitability for reliable wearable EMG acquisition without relying on signal amplification, but rather on effective noise management.
Beyond noise metrics, the study also investigated how electrode baseline characteristics influence neural model behavior under deployment conditions. Machine learning classifiers, including Support Vector Machine (SVM), Random Forest (RF), Decision Tree (DT), and K-Nearest Neighbors (KNN), were used to classify muscle activity states. The IJP electrodes showed nearly overlapping performance with gel electrodes in terms of false alarms per minute (FA/min), miss rate, precision-recall (PR), and ROC-AUC analyses. This indicates comparable neural detection reliability and class separability between active and rest states, with the RF model achieving a maximum accuracy of 95%.
Advancing Wearable Biosensors with Printed Electronics
This research underscores a fundamental principle in the development of advanced wearable biosensors: the critical importance of stable baseline noise characteristics for long-term reliability. By demonstrating that inkjet-printed dry electrodes, enabled by NovaCentrix’s advanced conductive inks, can achieve performance comparable to traditional gel electrodes while offering superior comfort and flexibility, this study paves the way for a new generation of wearable sEMG systems.
The findings suggest that future wearable EMG systems should prioritize baseline noise evaluation and electrode stability as key design objectives. Cleaner baseline signals expand the operational range of wearable EMG detectors, enabling more robust deployment under varying conditions and facilitating scalable edge-AI deployment. NovaCentrix is proud to contribute to such foundational research, enabling innovations that push the boundaries of printed electronics in health monitoring and human-machine interfaces.
Read the full paper: Mitra, N., & Morshed, B. I. (2026). Comparative Study of Baseline Noise Characteristics in Inkjet-Printed Ag-Nanoparticle Dry Surface EMG Electrodes with Gel Electrodes. 2026 IEEE International Conference on Electro Information Technology (eIT). https://ieeexplore.ieee.org/abstract/document/11670377/