A wearable electrochemical sensor based on β-CD functionalized graphene for pH and potassium ion analysis in sweat

Here, we developed a wearable electrochemical sensor for pH and K⁺ monitoring in sweat. The sensor was composed of flexible reference electrode, pH response electrode and K⁺ selective electrode, which were prepared through printing β-CD functionalized graphene (β-CD/RGO) water suspension on conductive PET substrate with microelectronic printer. β-CD/RGO not only served as the pH sensitive material for pH response electrode with good sensitivity, selectivity and reproducibility due to its abundant oxygen-containing functional groups, but also worked as the ion-to-electron transducer for K⁺ selective electrode with good sensitivity. The wearable sensor exhibited good potential stability at different bending states. On-body sweat pH and K⁺ measurements showed high accuracy compared with ex-situ analysis.