2004 Volume 73 Issue 1 Pages 28
Biological immunoassays utilizing a magnetic marker and a superconducting quantum interference device (SQUID) have been studied. In this method, the biological binding-reaction between an antigen and its antibody is detected by measuring the magnetic signal from the marker that is connected to the antibody. Three methods have so far been developed for the detection of the magnetic signal from the marker, namely, susceptibility, relaxation, and remanence measurements. It has been shown that these methods can detect the binding reaction with at least 10 times the sensitivity of the conventional optical method. It will be possible to develop a system whose sensitivity is 100 times that of the conventional system.
