An ACET capacitive biosensor for rapid and ultrasensitive detection of sweat uric acid

Integrated ACET aptasensor, microfluidic patch, and portable detector. • Rapid sweat collection (10 μL in 15 s) via PDMS capillary micro-channels. • Ultra-low LOD (75.43 aM), wide linear range (0.1 fM–10 pM), and high selectivity (2069: 1). • 2-min turnaround time, 21-day stability, and $ 50 system cost. Hyperuricemia is closely linked to uric acid (UA) levels, and conventional serum UA detection is invasive and time-consuming, limiting its suitability for rapid monitoring. Herein, an alternating current electrothermal (ACET) capacitive aptasensor is developed for fast detection of sweat UA. Benefiting from the powerful ACET effect for target enrichment and ultrasensitive interfacial capacitance sensing, the sensor achieves a low calculated detection limit of 75.43 aM within 30 s, along with a wide linear dynamic range from 0.1 fM to 10 pM and a high selectivity ratio of 2069: 1. A point-of-care testing platform integrating a microfluidic sweat-collection patch and a self-developed portable micro-capacitance detector is further constructed, capable of harvesting 10 μL of sweat within 15 s and testing instantaneous capacitance, allowing the total testing in less than 2 min including a dilution step. The platform is validated using diluted, spiked human sweat samples, demonstrating the feasibility of the sensor for rapid and non-invasive UA detection. Download: Download high-res image (278KB) Download: Download full-size image