3D Origami-Inspired Electrochemical Paper-Based Analytical Devices with Flow-Through Electrodes and Quasi-Steady Flow

Electrochemical paper-based analytical devices (ePADs) are an excellent choice to achieve the goal of global health due to their advantages of low cost, portability, and rapid analysis. However, the low sensitivity limits the application of ePADs. In this study, a 3D origami-inspired ePAD with flow-through electrodes and quasi-steady flow was presented for signal amplification to enhance the sensitivity. A Silhouette Studio plotter/cutter was used to design four schemes with a porous gold electrode as the working electrode. The flow-through electrode with quasi-steady flow exhibited the highest current due to enhanced convective transfer. The peak current of the device combined with flow-through porous electrodes with flow increased by 97.2 and 63.8% compared with the device without flow and the device combined flow-over electrodes with flow, respectively. The finite element simulation results showed that the current increased 10 times compared with the conventional saturated devices with flow-over electrodes and flow-through electrodes. Moreover, the evaluation of the device used copper ions as the detection species. The current of the device that combined flow-through with quasi-steady flow was about twice as large as other schemes and owned higher sensitivity. This strategy provides new insights and a more facile way to amplify signals of ePADs.