A stretchable wearable sensor with dual working electrodes for reliable detection of uric acid in sweat

Wearable sweat sensors with stretch capabilities and robust performances are desired for continuous monitoring of human health, and it remains a challenge for sweat sensors to detect targets reliably in both static and dynamic states. Herein, a flexible sweat sensor was created using a cost-effective approach involving the utilization of three-dimensional graphene foam and polydimethylsiloxane (PDMS). The flexible electrochemical sensor was fabricated based on PDMS and Pt/Pd nanoparticles modified 3D graphene foam for the detection of uric acid in sweat. Pt/Pd nanoparticles were electrodeposited on the graphene foam to markedly enhance the electrocatalytic activity for uric acid detection. The graphene foam with excellent electrical property and high porosity, and PDMS with an ideal mechanical property endow the sensing device with high stretchability (tolerable strain up to 110 %), high sensitivity (0.87 μA μM^-1 cm^-2), and stability (remaining unchanged for more than 5000 cycles) for daily wear. To eliminate possible interferences, the wearable sensor was designed with dual working electrodes, and their response difference ensured reliable and accurate detection of targets. This strategy of constructing sweat sensors with dual working electrodes based on the flexible composite material represents a promising way for the development of robust wearable sensing devices.