A Dual-Purpose Paper-based Electrochemical Device for Enzyme-free Sensing of Urinary Urea and Micro-Powering Applications
The Research group of Dr. Sweta Lal, Department of Chemical Engineering developed a novel paper-based urea fuel cell (PUFC) suitable for low-power applications alongside non-enzymatic sensing of urinary urea through a self-powered mechanism. Both the anode and cathode consist of cobalt oxide (Co?O?)-functionalized carbon nanotube (f-CNT) electrodes. The PUFC delivered linear response with increasing urea concentration. At 1 M urea, the device achieves an open-circuit voltage (OCV) of 1.22 V and a maximum current density (Jmax) of 634.92 microA/cm sq.. Further, a two-cell PUFC stack is capable of powering a digital thermometer using both urea and simulated urine, delivering a stable OCV of 2.5 V for ~2 hours. Next, the PUFC is employed as a self-powered sensor for urinary urea detection, achieving a sensitivity of 85.43 microW/mM/cm sq., a limit of detection (LoD) of 0.12 microM, and a limit of quantification (LoQ) of 0.41 microM. The PUFC sensor also exhibits excellent reproducibility (relative standard deviation, RSD = 6.5%), stable performance over multiple cycles (RSD = 9.6%), and a shelf life of ~10 days. This non-enzymatic, self-powered platform provides a reliable, low-cost, self-sustained, and portable solution for real-time urea monitoring and urinalysis, while also demonstrating strong potential for point-of-care (POC) kidney health diagnostics. For more details, kindly visit https://doi.org/10.1016/j.microc.2026.118076
