7. cPADs

Craft Paper-based Analytical Devices (cPADs) were simply made by craft punchers; and it doesn't require any electrical equipment, harmful chemicals, or sophisticated procedures.

The plasma separation technique was incorporated with cPADs for the rapid test of Total Antioxidant Capacity (TAC) using sub-µL blood samples. Instead of forming a droplet-based assay (Lab Chip, 2012, 12, 5225), the plasma separated in the tubing was directly deposited to cPADs for the testing. The developed color from the antioxidants in the blood mixing with pre-loaded reagents on each pedal was detected by utilizing an image thresholding analysis method in ImageJ. The areas are outlined by yellow lines as shown in the left bottom cPAD image.

The whole diagnostic process, including making the cPADs, plasma sample preparation, assay, and image thresholding analysis, can be completed in 15 minutes. In addition, both the paper and the separation tubing are low-cost and disposable.

RSC Adv., 2015, 5, 55633