Current development of materials science and engineering towards epidermal sensors

The epidermal sensor, a kind of wearable epidermal electronics, has become one of the rising research fields with vast applications because they are wireless, lighter, more flexible, compatible with human skin compared with conventional wearable sensors. A large number of physical and biochemical parameters of the human body, human motion, gases can be continuously sensed by epidermal sensors to real-time monitor human health and sports as well as the atmosphere in various environments. In this review, the state-of-the-art materials, e.g., one-dimensional (1D) nanomaterials, two-dimensional (2D) nanosheets, polymers thin film, and hydrogels applied in the epidermal sensors are discussed, and the practical applications are divided into three subtopics of epidermal sensors towards health monitoring, motion monitoring as well as gas monitoring and a prospective of applications of epidermal sensors is also discussed.