Digital Pregnancy Test Powered by an Air-Breathing Paper-Based Microfluidic Fuel Cell Stack Using Human Urine as Fuel

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 17; p. 6641
• Main Authors: Vera-Estrada, Irma Lucia, Olivares-Ramírez, Juan Manuel, Rodríguez-Reséndiz, Juvenal, Dector, Andrés, Mendiola-Santibañez, Jorge Domingo, Amaya-Cruz, Diana María, Sosa-Domínguez, Adrían, Ortega-Díaz, David, Dector, Diana, Ovando-Medina, Victor Manuel, Antonio-Carmona, Iveth Dalila
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-09-2022; MDPI
• Subjects: Analysis; Electric potential; Electrodes; Electrolytic cells; Fuel cell industry; Fuel cells; human urine; Human wastes; lateral flow assay tests; Medical equipment; Microfluidics; Nanoparticles; Oxidation; paper-based microfluidic fuel cell; Performance evaluation; Physiology; power supply; Pregnancy; pregnancy test; Pregnant women; Titanium dioxide; Urine; Voltage; Mexico; United States > US
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22176641

The direct integration of paper-based microfluidic fuel cells (μFC’s) toward creating autonomous lateral flow assays has attracted attention. Here, we show that an air-breathing paper-based μFC could be used as a power supply in pregnancy tests by oxidizing the human urine used for the diagnosis. We present an air-breathing paper-based μFC connected to a pregnancy test, and for the first time, as far as we know, it is powered by human urine without needing any external electrolyte. It uses TiO2-Ni as anode and Pt/C as cathode; the performance shows a maximum value of voltage and current and power densities of ∼0.96 V, 1.00 mA cm−2, and 0.23 mW cm−2, respectively. Furthermore, we present a simple design of a paper-based μFC’s stack powered with urine that shows a maximum voltage and maximum current and power densities of ∼1.89 V, 2.77 mA cm−2 and 1.38 mW cm−2, respectively, which powers the display of a pregnancy test allowing to see the analysis results.