Figure 1

Screenshot of the AutoPAD Tree Interface (right) with a single layer paper-based microfluidic device design shown in preview mode (left). A black box in the Node Tree highlights the commands used to result in the accurate placement of a rectangular channel (green) and circular test zone (red) at a defined angle of 240° (blue) relative to the first node of the device, as denoted by the >0 node command (gray).