A Ghanaian chemist has collaborated with other researchers at the Ohio State University to develop paper strips that detect diseases including cancer and malaria, for a cost of 50 cents per strip.
Abraham Badu-Tawiah, who is also the assistant professor of chemistry and biochemistry at the university said the idea was conceived to enable people in rural Africa and southeast Asia, where the disease kills hundreds of thousands of people, get a cheap way of diagnosing the disease.
Malaria is a mosquito-borne disease caused by parasites. The Centers for Disease Control and Prevention estimates that there were 214 million cases of malaria worldwide in 2015, and 438,000 people died, mostly children in Africa.
“In Africa, malaria is so common that whenever you get feverish, the first thing you think is, ‘Oh, it’s probably malaria,’” Badu-Tawiah said.
But with this technology, he said, all one needs to do is to apply a drop of blood to the paper at home and mail it to a laboratory on a regular basis, and see a doctor only if the test comes out positive.
“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,” Badu-Tawiah said.
The tests proved accurate even a month after the blood sample was taken, indicating that they could work for people living in remote areas.
“We want to empower people. If you care at all about your health and you have reason to worry about a condition, then you don’t want to wait until you get sick to go to the hospital. You could test yourself as often as you want,” Badu Tawiah said.
Explaining how the technology works, Badu Tawiah said the paper contains small synthetic chemical probes that carry a positive charge. It is these “ionic” probes that allow ultra-sensitive detection by a handheld mass spectrometer, he said.
“Enzymes are picky. They have to be kept at just the right temperature and they can’t be stored dry or exposed to light,” Badu-Tawiah said. “But the ionic probes are hardy. 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.”
The technology resembles today’s “lab on a chip” diagnostics, but instead of plastic, the “chip” is made from sheets of plain white paper stuck together with two-sided adhesive tape and run through a typical ink jet printer.
Instead of regular ink, wax ink was used to trace the outline of channels and reservoirs on the paper. The wax penetrates the paper and forms a waterproof barrier to capture the blood sample and keep it between layers. One 8.5-by-11-inch sheet of paper can hold dozens of individual tests that can then be cut apart into strips, each a little larger than a postage stamp.
Badu Tawiah and his colleagues are currently working hard to make the tests more sensitive, to enable people use them non-invasively, with saliva or urine as the test material instead of blood.
The university will soon license the technology to a medical diagnostics company for further development, and Badu-Tawiah hopes to be able to test the strips in a clinical setting within three years.