Liquid phase immunoassay utilizing magnetic marker and high Tc superconducting quantum interference device

K. Enpuku, K. Soejima, T. Nishimoto, H. Tokumitsu, H. Kuma, N. Hamasaki, K. Yoshinaga

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


We have developed a liquid phase immunoassay system utilizing a magnetic marker and a superconducting quantum interference device (SQUID). In this system, the magnetic marker was used to detect the biological material called antigen. The magnetic marker was designed so as to generate a remanence, and the remanence field of the markers that bound to the antigens was measured with the SQUID. The measurement was performed in a solution that contained both the bound and free (or unbound) markers, i.e., without using the so-called bound/free (BF) separation process. The Brownian rotation of the free markers in the solution was used to distinguish the bound markers from the free ones. Using the system, we conducted the detection of biological material called IgE without BF separation. At present, we could detect the IgE down to 7 pg (or 39 amol).

Original languageEnglish
Article number054701
JournalJournal of Applied Physics
Issue number5
Publication statusPublished - 2006

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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