A Wearable Electrochemical Biosensor Utilizing Functionalized Ti₃C₂T_<i>x</i> MXene for the Real-Time Monitoring of Uric Acid Metabolite

Abstract

Wearable, noninvasive sensors enable the continuous monitoring of metabolites in sweat and provide clinical information related to an individual<i>'</i>s health and disease states. Uric acid (UA) is a key indicator highly associated with gout, hyperuricaemia, hypertension, kidney disease, and Lesch-Nyhan syndrome. However, the detection of UA levels typically relies on invasive blood tests. Therefore, developing a wearable device for noninvasive monitoring of UA concentrations in sweat could facilitate real-time personalized disease prevention. Here, we introduce 1,3,6,8-pyrene tetrasulfonic acid sodium salt (PyTS) as a bifunctional molecule functionalized with Ti₃C₂T_<i>x</i> via π-π conjugation to design nonenzymatic wearable sensors for sensitive and selective detection of UA concentration in human sweat. PyTS@Ti₃C₂T_<i>x</i> provides many oxidation-reduction active groups to enhance the electrocatalytic ability of the UA oxidation reaction. The PyTS@Ti₃C₂T_<i>x</i>-based electrochemical sensor demonstrates highly sensitive detection of UA in the concentration range of 5 μM-100 μM, exhibiting a lower detection limit of 0.48 μM compared to the uricase-based sensor (0.84 μM). In volunteers, the PyTS@Ti₃C₂T_<i>x</i>-based wearable sensor is integrated with flexible microfluidic sweat sampling and wireless electronics to enable real-time monitoring of UA levels during aerobic exercise. Simultaneously, it allows for comparison of blood UA levels via a commercial UA analyzer. Herein, this study provides a promising electrocatalyst strategy for nonenzymatic electrochemical UA sensor, enabling noninvasive real-time monitoring of UA levels in human sweat and personalized disease prevention.