Cheap, simple diagnostic kits have the potential to revolutionize health care in the developing world. If we can put non-technical tests in the hands of normal people, we can test for diseases more efficiently without building out formal clinic networks. That should help get treatments to people in a more timely way.
One promising technology: paper and plastic strips that allow ordinary citizens to test for bacteria and viruses like HIV without the need for specialist assistance. Developed at Florida Atlantic University, Stanford University, and Harvard University, the strips are printed with bio-reactive chemicals along with electrical and optical sensors.
“If you are in a resource-constrained setting in Africa, they cannot afford the expensive health care infrastructure,” says Waseem Asghar, an assistant professor at FAU and one of the researchers behind the project. “You can do the test right way and then, to dispose of it, you can burn substrate without worrying.”
One test–for E.coli–is made of paper (cellulose) and printed with a mixture of antibodies and gold nanoparticles. If the bacteria is present, the antibodies are drawn to the blood sample and there’s a color change indicating a positive result. Cleverly, the paper has small grooves on it, so the sample spreads evenly and the color change is detectable.
“The idea is that if someone has a cellphone with our app, they can quantify how much color change there is, and from there, they can tell whether there is a pathogen or a bacteria [in the sample] and then send that to a doctor’s office,” Asghar says.
A paper summarizing the research is published in the journal Nature Scientific Reports. A separate plastic HIV test will be trialled soon at Brigham and Women’s Hospital, in Boston. Asghar hopes to commercialize within a year.
“If you have the substrate that is flexible, it can be produced locally in different regions of the world,” he says.