Waterproof and Gel-Free E-Textile Wearable Systems for Exercise Physiology and Maternal Health

Textile-based electronic systems have emerged as a promising platform for noninvasive and comfortable human-machine interfaces in various applications. These systems integrate multiple technological capabilities such as sensing and wireless communications, making them suitable for daily wearables and physiological monitoring in sports and clinical settings. This work presents a novel E-textile system consisting of printed on-textile electrodes and add-on conductive microfibers, enabling gel-free motion-artifact-tolerant recording of multiple physiological signals, including ECG and EMG from both skeletal and smooth muscles. More specifically, the base layout consists of a screen-printed array of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), and the fluffy microfibers coated with PEDOT:PSS are stacked on top. The vertically oriented hairy microfibers offer exceptional conformal and robust contact with the skin, while the spreading-out microfiber electrodes substantially increase the effective contact area. As a result, the contact impedance between the electrode and skin is significantly reduced, enabling comfortable all-day wear under dry conditions without the need for ionic gels. To ensure the durability and functionality of the textile, a self-assembled monolayer (SAM) of trichloro(1H,1H,2H,2H-perfluorooctyl) silane is vaporized as a superhydrophobic coating. This treatment preserves the natural physical properties of the textile while maintaining the intrinsic conductivity of the electrodes. Additionally, a portable mini-circuitry was designed and manufactured to enable multi-channel recording and wireless communications. These advancements contribute to the seamless integration of the E-textile system into everyday life and expand its potential applications. This study explores the application of E-textile systems in real-life scenarios, including strenuous exercise and clinical studies. The study begins by demonstrating the robustness and stability of the E-textile system using E-jersey and E-shorts during a 15-minute cycling training session. Remarkably, the recorded signals remained clear and free from motion artifacts, even in the presence of intense sweating, with a signal-to-noise ratio of approximately 30 dB. Real-time monitoring also allowed for additional real-time data analysis, including heart rate and muscle output. Next, the waterproof capability of the system was tested by creating an E-swimsuit with electrodes placed facing the swimmer's back. Throughout the 12-minute swimming training, the fully submerged E-swimsuit consistently delivered reliable ECG recordings, demonstrating its resilience and suitability for aquatic environments, even when encountering water flows, showcasing its strength and suitability for aquatic environments. Finally, the textile-based E-patch with electrode arrays was employed in clinical studies to monitor maternal health. Multiple pregnant subjects were monitored, capturing multichannel maternal-ECG and uterine-EMG signals. The recorded multichannel uterine-EMG signals were further processed to generate noninvasive and high-resolution three-dimensional (3D) electromyometrial images, providing unique insights into uterine behavior and offering a means of predicting the risk of potential preterm birth. These findings emphasize the versatility and potential of wearable E-textile systems in a wide range of real-world applications. The E-textile systems are specifically designed for convenient and comfortable wearing, paving the way for professional sports tracking and personalized healthcare advancements.