A silver nanowires@Prussian blue composite aerogel-based wearable sensor for noninvasive and dynamic monitoring of sweat uric acid

Abstract

Wearable sweat sensors have shown promise for noninvasive and dynamic monitoring of uric acid (UA), a key indicator in gout management. However, limited UA sensors are reported due to the low concentration in sweat and the inefficient sweat collection. Here, we presented a core–shell aerogel comprised by strongly conductive Ag nanowires (AgNWs) and highly active Prussian blue (PB) to continuously and accurately track sweat UA with the assistance of the microfluidic channel. The AgNWs@PB aerogel possessed a high intrinsic activity, a large active area and ample electron transfer pathways. In addition, the porous structure of the aerogel also provided abundant accessible channels, facilitating the diffusion of electrolyte and UA molecules. Therefore, the AgNWs@PB composite aerogel as a sensing unit demonstrated a high sensitivity of 50.6 µA mM−1 cm−2 towards UA detection, as well as a wide linear range. By integrating the microfluidic channel as a sweat collection unit, we tested the performance of the AgNWs@PB aerogel-based sensor in subjects before and after a purine-rich diet, the results of which were consistent with those detected by a commercial colorimetric assay kit. Furthermore, the as-prepared wearable sensor possessed a satisfactory accuracy in dynamic on-body monitoring of sweat UA within 12 h, which presented a good correlation with blood UA measured with a commercial UA meter. The personalized wearable sweat sensor has a great potential to provide the effective evidence for noninvasive UA control in future.