Clinical laboratory assays based on low-cost paper strip tests could make detecting malaria easier in rural areas of Africa and Southeast Asia
In the field of remote medical pathology, diagnostic tests strips made from paper can provide low-cost, simple-to-perform testing in developing nations. These are regions where such diagnostic test capabilities are desperately needed by medical laboratory scientists and resource-strapped clinical laboratories.
One such example is a new paper strip test that can detect malaria for people in rural areas of Africa and southeast Asia. Such tests could also lower the cost of diagnostic testing in other parts of the world. Research teams have been working on various paper-based tests for at least the last decade.
Ohio State University’s Paper Malaria Test Strip
Abraham Badu-Tawiah, PhD, Assistant Professor of Chemistry and Biochemistry at Ohio State University, (OSU) is a member of the team of chemists working on the project. In a paper published in the Journal of the American Chemical Society (JACS), the researchers stated that their new test strips could be used to test for many different conditions. In fact, the strips are capable of testing for any condition that causes the body to produce antibodies.
The research team has applied for a patent on the technology and is hoping to conduct clinical tests within the next three years. They expect that it will be most valuable in areas of Africa and Asia where residents have limited access to healthcare. In an interview with Fortune, Badu-Tawiah said, “We want to empower people,” adding that with this test, people who have reason to worry about specific conditions would not have to wait to go to the hospital to be tested.
The test strips work differently than more traditional tests, such as pregnancy tests, which are coated with enzymes and designed to change color. Badu-Tawiah’s test strips use chemical probes that carry a positive charge (called ionic probes), and which are designed to work in conjunction with a mass spectrometer. According to Badu-Tawiah, in order to use his new strips, “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.”
A single sheet of 8.5” x 11” paper could be used to make dozens of tests, because each one is just slightly larger than a postage stamp. The researchers used two-sided adhesive to hold the sheets of chemically-treated paper together, and ran it through a typical ink-jet printer. However, instead of regular ink, they used wax ink to create a barrier to hold the blood sample between the layers of the paper.
When the blood sample hits the test strip, the ionic probes extract the disease biomarker for which strip is designed to test. The biomarker remains in place until it undergoes mass spectrometry in a lab.
The researchers began with malaria and were successful in detecting the biomarker even when the blood was on the paper strip for a number of days.
Badu-Tawiah says that even the heat and arid conditions of rural Africa will not affect how the tests function, adding, “So, you can mail one of these strips to a hospital and know that it will be readable when it gets there.”
OSU Researchers Working to Develop Lower Cost Models
Such a test could save lives in areas where malaria is common. Experts estimate that many of the 438,000 people who died of malaria in 2015 were children in rural Africa. Although the test strips cost only about 50¢ each to make, there would be an initial cost for hospitals to purchase the mass spectrometers they would need to read the tests, some of which cost as much as $100,000. The researchers are working to develop less expensive models. Badu-Tawiah believes the investment in spectrometry equipment would be offset by gains in worker productivity.
Since the paper strip test could also be used to test for various types of cancer and other antibody-producing diseases, they also could be useful in places where malaria is fairly uncommon, such as the United States. Badu-Tawiah suggests that people who are recovering from cancer would be able to test themselves at home rather than going to the doctor every six months to make sure the disease is still in remission.
The Need for Paper-Based Tests
Dark Daily has often reported on paper strip tests. In 2014, such a test was developed to be used in conjunction with an injection of exogenous agents under development at the Massachusetts Institute of Technology (MIT). The test can detect the biomarkers of colorectal cancer and thrombosis. Researchers believe it will lead to similar tests for a range of non-communicable diseases. (See Dark Daily, “MIT Researchers Detect Cancer from Urine Specimens by Combining Synthetic Biomarkers with Paper-based Diagnostics,” April, 30, 2014.)
Another such test involving a biosensing film is being studied at Florida Atlantic University (FAU). It is similar to paper strip tests in that it doesn’t require expensive equipment or even a medical pathology lab to be functional. The developers say it can detect HIV, Staphylococcus, and E-coli, among other bacteria. The film works in conjunction with a smartphone app. (See Dark Daily, “New Biosensing Film Can Diagnose Both Viral and Bacterial Infections Cheaply and Without the Need for Traditional Clinical Pathology Laboratory Tests,” September 18, 2015.)
And in February of 2016, researchers at the University of Rhode Island (URI) announced they were working on a paper strip test that could test for multiple conditions on a single strip. It works similarly to a pregnancy test, except it is capable of “sequential manipulation of sample fluids and multiple reagents in a controlled manner to perform complex multi-step immune-detection tests without human intervention,” according to a press release from the company the researchers organized in order to explore how the strips might be commercialized. (See Dark Daily, “Researchers at University of Rhode Island Unveil Lab-on-Paper Test Capable of Multireagent Diagnostics: Could Enable ‘Diagnostics Without the Lab’ say Developers, February 10, 2016.)
The sheer number of research teams working toward paper strip tests demonstrates the need for such technology. Inexpensive diagnostic tests that can be self-administered could change the face of rural healthcare, and have an enormous impact on the operations of clinical medical laboratories in the United States and other developed countries as well.