Flexible and printable integrated biosensors for monitoring sweat and skin condition.

Wearable and flexible sensors are playing increasing roles in health monitoring (like physiological electrical signals and components of biofluids). Therein, sweat as a carrier of informative biomarkers would attract great attention for health status identification. However, most wearable biosensors have a short lifetime with complex fabrication processes and expensive costs, which would largely limit the application scene to some extent. Here, we developed a state-of-the-art flexible and integrated sensor patch with screen-printing technology for in-situ and real-time monitoring of electrolyte balance and skin state. The screen-printed sensor patch was easily fabricated, highly reproducible, disposable and relatively stable, which was extremely for sweat sensors with low cost. The state of art sensors on the patch of Na, pH, skin impedance and temperature all showed excellent performance with high linearity (coefficient of determinations (R) are 0.998, 0.994, 0.998 and 0.997, respectively). Besides, the detection ranges of Na and pH sensors are wide enough for sweat analysis of 10-100 mM and 2-8, respectively. The proposed device provides a new strategy for real-time sweat analysis, preventing dehydration and skin state monitoring during exercise.