Microfluidic\nWearable Electrochemical Sensor Based\non MOF-Derived Hexagonal Rod-Shaped Porous Carbon for Sweat Metabolite\nand Electrolyte Analysis

Wearable sensors enable the noninvasive\ncontinuous analysis\nof\nbiofluid, which is of great importance for healthcare monitoring.\nIn this work, a wearable sensor was seamlessly integrated with a microfluidic\nchip which was prepared by a three-dimensional printing technology\nfor noninvasive and multiplexed analysis of metabolite and electrolytes\nin human sweat. The microfluidic chip could enable rapid sampling\nof sweat, which avoids the sweat evaporation and contamination. Using\na Zn metal–organic framework as a sacrificial template, the\nhexagonal rod-shaped porous carbon nanorod (PCN) with high porosity,\na large specific surface area, and excellent conductivity was synthesized\nand exhibited the robust electrocatalytic ability of uric acid (UA)\noxidation. Therefore, the PCN-based sensor showed high sensitivity\nand good selectivity of UA with a wide linear range of 10–200\nμM and a low detection limit of 4.13 μM. Meanwhile, the\npotentiometry-based ion-selective electrode was constructed for detection\nof pH and K<sup>+</sup>, respectively, with good sensitivity, selectivity,\nreproducibility, and stability. In addition, the testing under different\nbending states demonstrated that mechanical deformation had little\neffect on the electrochemical performance of the wearable sensors.\nFurthermore, we evaluated the utility of the wearable sensor for multiplexed\nreal-time analysis of UA, pH, and K<sup>+</sup> in sweat during aerobic\nexercise, and the effect of the amount of consumed purine-rich foods\non uric acid metabolite levels in sweat and urine was further investigated.\nThe relationship between urine UA and sweat UA was obtained. Overall,\nthis wearable sensor enables multiple electrolyte and metabolite analysis\nin different noninvasive biofluids, suggesting its potential application\nin personalized disease prevention.