NEW YORK (360Dx) – Purdue University researchers have fabricated a microfluidic test prototype from paper that could eventually be used at the point of care to detect biomarkers such as glucose, uric acid, L-lactate, ketones, and white blood cells that are used in the clinical analysis of liver and kidney function, malnutrition, and anemia.
The test could be particularly suitable for use in remote locations without electricity or clean water, and it has been designed to be easy enough to operate even by untrained people, the researchers said. The technology works by pressing on a piece of paper and triggering an electrochemical analysis that results in a color-coded readout, the researchers said.
"We hope these devices will serve untrained people located in remote villages or military bases to test for a variety of diseases without requiring any source of electricity, clean water, or additional equipment,” said Ramses Martinez, an assistant professor of industrial and biomedical engineering at Purdue University, and the coauthor of a study published Tuesday in the journal Advanced Materials Technologies describing the test.
The self-powered, paper-based electrochemical device is initiated by placing a pinprick of blood in a small circular region on the device. Alternatively, a pipetting test zone can be dipped into the sample.
The test changes color to indicate a result. Machine-vision software automatically identifies and quantifies each test using a digital image of the device. Imaging could potentially be done using a cellphone, and would provide fast diagnostic results to the user and facilitate remote-expert consultation, the researchers said.
Purdue noted that it's possible to manufacture the microfluidic test by roll-to-roll printing or spray deposition. The top layer is untreated cellulose paper with patterned hydrophobic regions that define microfluidic channels and that wick up blood samples for testing, the researchers said.
The bottom layer is a triboelectric generator that provides the electric current needed to run the test. An inexpensive handheld potentiostat, which can be recharged using the triboelectric generator, automates the test and makes it easier to operate, the researchers said.
Purdue noted that the device can perform multiplexed analyses "enabling highly sensitive and accurate detection of various targets for a range of point-of-care testing applications." Future versions of the test will consist of additional layers for more complex assays to detect diseases such as dengue fever, yellow fever, malaria, HIV, and hepatitis, Martinez said.