A high-Tc SQUID system is developed for the application to biological immunoassay, i.e., for the detection of an antigen with a magnetically labeled antibody. In order to improve the system performance, two issues are studied. One is the use of a gradiometer to suppress the system noise due to residual environmental noise. It is shown that the noise of the gradiometer system is five times smaller than that of the magnetometer system. The other is to increase the signal field from the magnetic marker. The signal can be increased by increasing an applied field Bex or by using remanence of the marker. If these improvements were fully developed, it will be possible to develop the system that is 100 times more sensitive than the conventional optical method.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering