Emerging Advances of Liquid Metal toward Flexible Sensors

With the rising demand for biosignal detection, many wearable sensors emerge in recent years. Such a new generation of sensors relies on major breakthroughs in soft sensing materials, which can be bent, compressed, and stretched in a large range. Ga-based liquid metals (LM) offer a unique combination of high deformability, electrical conductivity, and biocompatibility, making them ideal functional candidate materials for wearable sensors. Numerous studies design various LM sensors for detecting and modulating diverse signals. Nevertheless, further systematic discussion is still missing regarding their operational mechanism, structure defects, and potential solutions. In this review, recent progress in the application of Ga-based LM sensors is summarized and discussed, with a focus on the sensing principles corresponding to distinct LM properties, the problems, and solutions to each type of sensor. The key challenges toward biosignal detection and future research orientations are discussed.