Biological Immunoassay Utilizing Magnetic Marker and High T_cSuperconducting Quantum Interference Device Magnetometer

Abstract

Detection of the biological binding-reaction between an antigen andits antibody was performed by using a magnetic marker and a high Tc superconducting quantum interference device (SQUID) magnetometer. In this method, the binding reaction is detected by measuring the magnetic field from the marker. A new marker made of Fe3O4 particle with diameter of 25 nm was developed, and the remanent field of the marker was used for the detection of the antigen called Interleukin 8 (IL8). It was shown that the present system can detect 0.1 pg weight of IL8.