Design of superconducting quantum interference device for magnetic immunoassays

Keiji Enpuku, Akihiro Ohba, Katsuhiro Inoue, Kazuyuki Soejima

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


A superconducting quantum interference device (SQUID) for application to biological immunoassays has been designed. In this application, the magnetic field from a magnetic marker made of magnetic nanoparticles is detected with the SQUID. It is shown that the conventional design of the SQUID that was developed for the case of uniform magnetic field cannot be used in this application, since the spatial variation of the magnetic field from the marker is large. Therefore, a numerical simulation method is developed for obtaining a signal flux detected with the SQUID when the magnetic field changes spatially. It is shown that the signal flux strongly depends on the geometrical parameters of the measurement system, such as the size of the pickup coil, size of the sample and the distance between the sample and the SQUID. The dependence of the signal flux on these geometrical parameters is quantitatively clarified, and the optimum design of the SQUID for the application to magnetic immunoassays is discussed.

Original languageEnglish
Pages (from-to)6044-6049
Number of pages6
JournalJapanese Journal of Applied Physics
Issue number9 A
Publication statusPublished - Sept 2004

All Science Journal Classification (ASJC) codes

  • General Engineering
  • General Physics and Astronomy


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