Droplet of the Test Liquid (IMAGE) Moscow Institute of Physics and Technology Caption A droplet of the test liquid is applied to the strip (1). The liquid, which spreads along the strip due to capillary action, captures magnetic particles that are "linked" with antibodies to the test protein (2). As they move along the strip, the particles bind to the required protein. The liquid then meets two lines -- the test line (3) and the control line (4). The test line contains antibodies that capture the protein and also the magnetic markers that were bound to it. The control line is activated in any case if the test strip is suitable for use. Credit Image courtesy of MIPT Press Service. 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.