Scientists have developed an affordable, quick test for a number of common infectious diseases including HIV, flu and dengue fever. Researchers at Eindhoven University of Technology in the Netherlands and Keio University in Japan found a way to test for the presence of antibodies in the blood using a strip of paper and a camera. The paper is mixed with a luminous sensor protein that emits blue light when it encounters blood, which is then converted to green light in a second step that confirms the presence of pathogens for a specific disease. A result for several diseases will emit blue light. Paper is inexpensive and readily absorbs blood samples, making it a perfect choice for the new device. According to Prof Maarten Merkx, a researcher in the department of Biomedical Engineering at the Eindhoven University of Technology, after applying a drop of blood to the paper strip, the clinician waits 20 minutes to detect the colour of the light emitted using a smartphone camera. “A biochemical reaction causes the underside of the paper to emit a blue-green light. The bluer the colour, the higher the concentration of disease antibodies,” said Prof Merkx who is one of the study’s lead authors. According to the researchers, the test does not require the time-consuming process of measuring the sample in a pipette, liquid handling or analytical equipment before subjecting it to various tests. They reported success in the study, saying the paper test produced accurate results for HIV, flu and dengue fever samples tested. “Simultaneous detection of three different antibodies (anti-HIV1, anti-HA, and anti-DEN1) in whole blood samples was achieved,” said the scientists. The study titled Paper-Based Antibody Detection Devices Using Bioluminescent BRET-Switching Sensor Proteins, was published in the October 3 edition of Eindhoven University of Technology journal Angewandte Chemie. The test can quickly provide accurate results for clinicians in remote locations who lack laboratories. In such areas, healthcare workers struggle to provide adequate healthcare to patients and often have to rely on lab tests in faraway locations to confirm findings on the condition to be treated. The delay in obtaining test results leaves the patients at a disadvantage, often resulting in worsening of their condition. Scientists hope that the test will be commercially available within a few years. The East African