Researchers are developing a special process meant to replace the custom "paper" found in home pregnancy and other tests with plain old office paper -- a way of creating ultracheap methods of medical testing that could quickly diagnose pregnancy, malaria, diabetes, and more.
Ultimately, the idea is to replace the current standard, which relies on a membrane called nitrocellulose that sticks to molecules of interest, with cheap and ubiquitous paper that can stick to a whole fleet of chemicals, including DNA, antibodies, and sugars. And a University of Washington researcher wants to make the already cheap tests even cheaper, so he's engineered plain old office paper to do the trick instead.
"We want to develop something to not just ask a single question but ask many personal health questions," Daniel Ratner, a UW assistant professor of bioengineering and lead author of a paper published in the American Chemical Society journal Langmuir, said in a school news release. "Is there protein in the urine? Is this person diabetic? Do they have malaria or influenza?"
Ratner says his team used an industrial solvent called divinyl sulfone that's been used as an adhesive for decades. By diluting the chemical in water and controlling the acidity, they could add it and a stack of paper into a Ziploc bag, shake (for a few hours), rinse, and let the paper dry.
While they say the paper feels smooth, it's actually sticky on a molecular level. "We wanted to go for the simplest, cheapest starting material, and give it more capability," Ratner said. "We also wanted to make the system as independent of the end applications as possible, something any researcher could plug into."
As they write in Langmuir, the researchers ran this treated paper through an inkjet printer that held the sugar galactose in place of cartridge ink. After printing the biomolecules onto the paper in an invisible pattern, they then exposed the paper to fluorescent ricin (a poison that sticks to galactose) to reveal its presence.
Ratner says his team hopes others will take this proof of concept and develop ultracheap diagnostic tests. They're already working with a grad student in the lab of Paul Yager, a UW bioengineering professor at the helm of the Microfluidics 2.0 initiative, to print patterns of switchable networks on the paper.