Chemists have developed a way to test for cancers, malaria, and other diseases using little more than a strip of paper, a drop of blood, and a postal envelope.
The researchers explain how the strips work in a paper published in the Journal of the American Chemical Society. Essentially, they work by detecting antibodies – proteins that the immune system releases in response to a virus, bacteria, or parasite – in a person’s blood.
The strips contain ionic probes that carry a positive charge. These probes tag specific antibodies that extract the disease biomarker from the blood and onto the paper chip. Then back at the lab, they’re dipped in ammonia and put in front of a mass spectrometer. This detects the probes based on their atomic characteristics and therefore is able to highlight the presence of biomarkers in an infected person's blood.
“To get tested, all a person would have to do is put a drop of blood on the paper strip, fold it in half, put it in an envelope and mail it,” lead researcher Abraham Badu-Tawiah, assistant professor of chemistry and biochemistry at Ohio State University, explained in a statement.
It’s all ludicrously simple to use. But the team are working to make the tests more sensitive, in hope that people can use saliva or urine as a test material, instead of blood.
Most “miraculous” of all, each strip costs just 50 cents – and this price is likely to go down with mass-production. The researchers say that the simplicity and low cost of the technique mean it could be used to screen for diseases in rural pockets of Africa and southeast Asia. The fact the strips are still viable up to a month later is especially helpful for those living in remote communities with infrequent mail.
“They are not affected by light, temperature, humidity – even the heat in Africa can't do anything to them. So you can mail one of these strips to a hospital and know that it will be readable when it gets there," Badu-Tawiah said.
“Although this approach requires an initial investment, we believe the low-cost paper-based consumable devices will make it sustainable,” he added. “We can set one small instrument at a grocery store, then sell the paper strips for just 50 cents per test. The same for Africa, and perhaps much cheaper there.”
The strips are still in the prototype stage of development. However, the team of researchers has already demonstrated their ability to accurately detect biomarkers from the most common malaria parasite (Plasmodium falciparum), the protein biomarker for ovarian cancer (cancer antigen 125), and the marker for large intestine cancers and numerous other cancers (carcinoembryonic antigen).
