Integrated multimodal microfluidic E-skin powered by synergistic tandem nanogenerators for sweat-based health monitoring and skin-temperature analysis

Wearable sweat biosensors, as the only noninvasive and measurable body-fluid sensors, serve as a very important means to monitor an individual’s health status and more dynamic molecular-level information. The pursuit of wearable sweat biosensors includes not only detecting sweat components, but also integrating multiple functions, such as sweat-based health monitoring, near-field transmission and being self-powered. In this paper, we firstly bring forth a new idea of integrating sweat monitoring and dual electrical generation (hydrovoltaic and moisture electricity generation) for a multifunctional flexible device as a sweat-based health monitoring electronic (E)-skin. Herein, besides sweat composition analysis, a hydrovoltaic electricity generator is employed to detect the amount of sweat for the first time, and a dual electricity generator is used for self-supply of energy and skin-surface temperature measurement. Synergistic tandem nanogenerators are constructed using biomass carbon materials, and the power generation voltage can reach about 500 mV and is relatively stable. Our sweat E-skin (SE-skin) has five main functional areas, realizing real-time monitoring of sweat volume, sweat composition analysis‚ skin-surface temperature measurement and power-supply functions. This new integrated design not only enables real-time monitoring of indicators of health in sweat, but also provides a new idea for future intelligent wearables for human beings.