A highly specific wearable sensor based on o-phenylenediamine molecular imprinting for sweat creatinine detection

Dynamic assessment of renal function has become a critical requirement in clinical and health management. Existing detection methods primarily rely on samples such as blood or urine, posing significant challenges for portable, continuous, real-time monitoring. This study introduces a novel wearable electrochemical biosensing platform based on sweat analysis for non-invasive detection of creatinine, a key biomarker of renal function. The platform employs o-phenylenediamine as a functional monomer to construct a molecularly imprinted polymer recognition layer. Leveraging the multi-point hydrogen bonding interactions provided by its o-diaminic groups, this layer forms strong and specific bonds with creatinine, endowing the sensor with high molecular specificity and anti-interference properties. The system integrates a flexible skin-adhesive interface, an electrochemical detection unit, and a pentagonal star-shaped sweat collection module. It induces localized sweating at rest via built-in electrodes, enabling efficient transport and real-time analysis of fresh sweat. The sensor exhibits excellent linear response characteristics across a concentration range of 0.1 to 400 μM, with two linear regions, both showing correlation coefficients R² > 0.99. The platform demonstrated stable detection performance in authentic human sweat samples. Tests evaluating circadian variations in sweat creatinine and the impact of protein intake confirmed the sensor's ability to capture fluctuations linked to dietary intake and physiological rhythms. This validates its feasibility for non-invasive, dynamic monitoring of renal function. This wearable device platform shows significant potential as a sweat biomarker monitoring tool, offering possibilities for convenient tracking and personalized management of kidney health.