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

The direct integration of paper-based microfluidic fuel cells (mu FC's) toward creating autonomous lateral flow assays has attracted attention. Here, we show that an air-breathing paper-based mu FC 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 mu FC 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 similar to 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 mu FC's stack powered with urine that shows a maximum voltage and maximum current and power densities of similar to 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.

Automated summary

This study investigates the application of paper-based microfluidic fuel cells in pregnancy tests, demonstrating the possibility of using human urine as an electrolyte to power the battery. The experimental results show high voltage and current, providing stable power supply for pregnancy tests.