Flexible textile strain sensors that can be directly integrated into clothing have attracted much attention due to their great potential in wearable human health monitoring systems and human–computer interactions. Fiber- or yarn-based strain sensors are promising candidate materials for flexible and wearable electronics due to their light weights, good stretchability, high intrinsic and structural flexibility, and flexible integrability. This article investigates representative conductive materials, traditional and novel preparation methods and the structural design of fiber- or yarn-based resistive strain sensors as well as the interconnection and encapsulation of sensing fibers or yarns. In addition, this review summarizes the effects of the conductive materials, preparation strategy and structures on the crucial sensing performance. Discussions will be presented regarding the applications of fiber- or yarn-based resistive strain sensors. Finally, this article summarizes the bottleneck of current fiber- or yarn-based resistive strain sensors in terms of conductive materials, fabrication techniques, integration and performance, as well as scientific understanding, and proposes future research directions.

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The present study introduced a new biomedical engineering concept to realize the real-time adjustment of nutrient absorption. With the aid of a 3D-printed wearable external magnet device, both the location and vibration of entericcoated magnetic nanoparticles (EMNPs) in the small intestine could be controlled directly. Through a facile mobile app, gastrointestinal motility could be monitored directly in real time. Further tests revealed that this technology could be an attractive way to adjust one's weight without diet or exercise modification.

Highly integrated, low-cost and multi-functional electronic data gloves have attracted extensive attention in the Age of the Internet of Things. While significant progress has been made in the design of strain sensors with wide strain ranges, it is challenging to integrate high linearity, broad strain sensing range, and fast response into a single type of strain sensor, and these sensing properties play a critical role in the development of high-performance data gloves. Herein, this study presents a highly flexible, stretchable, and sensitive silver nanoparticles/double covered yarn (AgNPs/DCY) composite yarn, and this yarn as strain sensor achieves broad strain sensing range (50%), ultralow detection limit (0.05%), high linear sensitivity (GF = 10), instant response time (24 ms) and high repeatability, simultaneously. Interestingly, the AgNPs of the AgNPs/DCY composite yarns fabricated by in situ reduction are observed to not only evenly distributed on the fiber surface of DCY, but also within core fiber, and this distribution and the DCY structure; that is, the cooperative sensing effect of microcrack propagation of conductive layer on fibers and the electrical contact resistance contributes to the good sensing performance. Additionally, this composite yarn as strain sensor is invisibly integrated into textile data gloves and the capability of real-time monitoring various finger motions and effectively recognizing sign languages demonstrates the good sensing performance and practicability of the developed composite yarn. Therefore, the composite yarn as strain sensor has great prospects in wearable electronics.