Figure 10.

Schematic illustration of the COVID-19 electrochemical paper-based analytical device (ePAD): (A) device components, (B) detection procedure. The device was printed using a wax printer. The ePAD consists of 3 folding layers: a working ePAD, a counter ePAD, and a closing ePAD. The hydrophilic center of each zone was limited by a wax barrier, where the solution could flow through to the test zone at the bottom. Three electrodes were then screen printed at the back of the device. Reprinted from [144]. Published by Elsevier with open access.