Scheme of the Test Strip Work (IMAGE) Moscow Institute of Physics and Technology Caption The antigen is the test protein (e.g. PSA). MP is the magnetic nanoparticle, the upside down Y is the antibody to the test protein. The test antibodies (the blue Ys) capture the test protein, and the control antibodies (the yellow Ys) capture the antibodies with the nanoparticles. Credit Image courtesy authors of the study Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.