Modern medicine can provide effective treatment for a huge number of diseases and conditions. The problem is that these treatments cannot be applied until the problem has been successfully diagnosed. And in many cases, diagnosis relies on the analysis of blood, urine, or other samples. This analysis often requires expensive and complex lab equipment, and it can take time for the results to come back. Time and money are two items that are in short supply in under-developed regions, and even developed countries could benefit from medical lab testing that is inexpensive and quick.
Researchers at Purdue University have developed a system that addresses these problems. A piece of paper less than two inches square can contain chemical tests for a 10 or more tests. Even more importantly, it includes a triboelectric generating layer that harvests static electricity to power the device; the user only has to tap or rub the paper to create the required electricity. The developers call it a Self-powered Paper-based Electrochemical Device, or “SPED”. Apply a drop of blood or other fluid to one of the target zones, or dip a corner into a sample to use its self-titrating feature. Separate hydrophobic and hydrophilic areas guide the sample fluids to the test areas. Results are displayed on pads that change color, depending on the levels of target chemicals in the sample. The color results can be analyzed by a smartphone app, providing valuable information in minutes.
The system does not require sophisticated training, and does not depend on a separate source of electricity, clean water, or any additional equipment. The devices can be fabricated using existing roll-to-roll or ink jet printing. The result is a low cost device that can be disposed of simply and safely, simply by burning it. Prototypes have been developed to measure important biomarkers, including glucose, uric acide, L-lactate, ketones, and white blood cells. The researchers plan to create future versions that could help diagnose dengue fever, malaria, yellow fever, hepatitis, and HIV. While this approach could certainly save lives in under-developed regions, this technology could provide great benefits for healthcare professionals and their patients worldwide.