The human body makes specific antibodies against the invasion of viruses and pathogens.The paper chip test developed this time confirms the presence or absence of infectious diseases by detecting the antibody in the blood.

　The inspection chip is made of paper and is about 1 cm in size.When blood is dropped on a paper chip, blue to green light is emitted in about 20 minutes, and the test result is revealed.A digital camera such as the camera attached to the mobile phone is sufficient for light detection, and it is possible to judge the effect clearly.

　The light emitted from the paper chip is due to the so-called "bioluminescence sensor protein" developed by Eindhoven University of Technology.When a blood sample and a detection reagent incorporated in a chip are mixed and a biochemical reaction occurs, luminescence is obtained.

　Sensor proteins are the same type of enzyme that light-emitting deep-sea organisms have, and in the absence of the target antibody in the sample, blue luminescence is converted to green luminescence.On the other hand, in the presence of the antibody, the antibody binds to the sensor protein, the emission color conversion process is blocked, and blue emission is confirmed.The greener the luminescence, the less the antibody in the sample, and conversely, the bluer the luminescence, the more the antibody.
　As a prototype, the research group has succeeded in simultaneously detecting three types of antibodies (anti-HIV, anti-influenza, and anti-dengue fever).It is expected that this paper chip will not only reduce the cost and time required for examinations in hospitals, but will also contribute as a simple examination method for tropical diseases in developing countries.

Paper information:[Angewandte Chemie International Edition] Paper-Based Antibody Detection Devices Using Bioluminescent BRET-Switching Sensor Proteins