Taking their cues from the ancient art of origami, chemists at the University of Texas at Austin have swapped folded boats and swans for a three-dimensional sensor crafted from paper that may be able to test for diseases like malaria and HIV for less than a dime each.
Imagine such low-cost, "point-of-care" sensors in the developing world -- lab-free lab results in places where the resources often don't exist to pay for labs, and where just as often, labs are few and far between."This is about medicine for everybody," says Richard Crooks, the Robert A. Welch Professor of Chemistry.
The sensors have been tested successfully on glucose. Crooks explains that the ideas behind the sensor are related to the home pregnancy test. A hydrophobic material, such as wax or photoresist, is applied in small canyons on chromatography paper. The channels direct the samples (urine, blood, or saliva) to places on the paper where test reagents have been embedded.
Inspired by Art
Graduate student Hong Liu (above) was inspired by the origami lessons he had growing up in China. Taking paper tests a step further than one-dimensional paper sensors (like pregnancy tests), the folded sensors can test for more substances in a smaller surface area and provide results for more complex tests.
Crooks and Liu have also designed a brilliant way to add a simple battery to the sensor so that no power is required to run the test. The prototype uses aluminum foil and detects for glucose in urine. It's estimated that including a battery like this would add only a few cents to the cost of producing the sensor.
"Anybody can fold them up," says Crooks. "You don't need a specialist, so you could easily imagine an NGO with some volunteers folding these things up and passing them out. They're easy to produce as well, so the production could be shifted to the clientele as well. They don't need to be made in the developed world."
The results of the team's experiments with the origami Paper Analytical Device, or oPAD, were published in October in the Journal of the American Chemical Society and this week in Analytical Chemistry.