Self-Powered Uric Acid Monitoring with CuInSe ₂ Nanozyme Catalysts

Noninvasive monitoring of uric acid (UA) in sweat is crucial for the early diagnosis of gout, hyperuricemia, and hypertension. However, the existing sweat UA sensors overrely on external power and lack sufficient longevity for continuous and reliable biofluid monitoring. Herein, we report a self-powered paper-based sweat sensor (SPSS) for noninvasive UA detection, which utilizes a galvanic cell structure decorated with CuInSe2 as a pseudoenzymatic catalyst. The sensor was fabricated by immobilizing hydrothermally synthesized CuInSe2 nanozymes onto NaCl-soaked paper substrates followed by encapsulation with copper and aluminum foils serving as electrodes. The SPSS demonstrated a wide linear detection range (1–200 μM) and dual-segment sensitivity (2.287 A·M–1 for 1–10 μM and 0.214 A·M–1 for 10–200 μM). Furthermore, a low limit of detection of 1 μM and rapid response time of 2.8 s enable real-time and active tracking of sweat UA levels arising from high-purine food intake and intense exercise, which is consistent with physiological variations. This work opens up a paradigm for noninvasive biofluid monitoring with the merits of zero-power consumption, simple structure, low cost, and environmental friendliness.