In a few years, testing yourself for cancer or malaria could be as easy as testing your blood sugar or taking a home pregnancy test, according to a recent study.
Chemists at the Ohio State University are developing paper strips that detect diseases including cancer and malaria for a cost of 50 cents per strip. Researcher Abraham Badu-Tawiah explained that the idea is that people could 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. The researchers found that the tests were accurate even a month after the blood sample was taken, proving they could work for people living in remote areas.
Badu-Tawiah conceived of the papers as a way to get cheap malaria diagnoses into the hands of people in rural Africa and southeast Asia, where the disease kills hundreds of thousands of people and infects hundreds of millions every year.
He and his colleagues report that the test can be tailored to detect any disease for which the human body produces antibodies, including ovarian cancer and cancer of the large intestine. The patent-pending technology could bring disease diagnosis to people who need it most–those who don’t have regular access to a doctor or can’t afford regular in-person visits, Badu-Tawiah said. “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,” he said.
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, however, the researchers use wax ink 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. “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 technology works differently than other paper-based medical diagnostics like home pregnancy tests, which are coated with enzymes or gold nanoparticles to make the paper change color. Instead, the paper contains small synthetic chemical probes that carry a positive charge. It’s these “ionic” probes that allow ultra-sensitive detection by a handheld mass spectrometer. The university will 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. In the meantime, he and his colleagues are working to make the tests more sensitive, so that people could eventually use them non-invasively, with saliva or urine as the test material instead of blood.
The study appears in the Journal of the American Chemical Society.
Thu, 30 Jun 2016