Home pregnancy tests use simple, one-dimensional paper sensors to detect a hormone called hCG that increases at the onset of pregnancy. Now, chemists at The University of Texas at Austin have developed an analogous, but 3-D, paper sensor that can provide results for complex tests such as malaria and HIV and can be printed on an ordinary office printer for a cost of less than 10 cents apiece.
The origami-like sensors work like a home pregnancy test—a hydrophobic material such as wax is printed into tiny channels on chromatography paper. Those channels direct the sample—urine, blood, or saliva—to spots on the paper where test reagents have been embedded, which react by turning a specific color, for example. The reagents could test for biomarkers that already exist for a range of diseases, including HIV, malaria, and diabetes. “At the end you unfold this piece of paper, and if it’s one color, you’ve got a problem, and if not, then you’re probably OK,” Crooks said in the release. The proof-of-principle prototype sensor uses aluminum foil and detects glucose in urine.