Printed graphene/CNTs/TPU-fabric wearable strain sensor for healthcare monitoring

Wearable strain sensors hold immense promise in monitoring human motion activities due to their low cost, lightweight design, and excellent biocompatibility. For example, continuous real-time monitoring of neck activity can effectively prevent the onset of acute torticollis. However, current approaches to monitoring sleep neck posture primarily depend on technologies such as computer vision, which are characterized by limited wearability and portability issues. Herein, this work introduces a cost-effective, highly sensitive carbon-based strain sensor fabricated on a fabric substrate with a printing technique, which is eco-friendly and biocompatible. The proposed sensor displays a broad sensing range of 112%, high sensitivity (gauge factor > 210), low sensing limit (~ 0.1 ‰), and outstanding long-term stability over 3,000 cycles. The sensor’s utilization in monitoring joint motion, vocal cord activity, pulse, and electrocardiogram (ECG) is illustrated. Moreover, a portable system for monitoring neck activity and ECG signals while sleeping has been engineered, capable of detecting neck movements and ECG signals during sleeping hours. The composite materials design strategy combined with printing techniques provides a potential route for high-performance and low-cost wearable strain sensors in health monitoring.