Application of HTS SQUIDs to biological immunoassays

Keiji Enpuku, Akihiro Ohba, Katsuhiro Inoue, Tong Qing Yang

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Biological binding-reaction between an antigen and its antibody was detected by using a magnetic marker and a high Tc superconducting quantum interference device (SQUID). 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. Issues for the improvement of the system performance were also discussed, such as binding efficiency of the marker to IL8 and the dependence of the signal flux on the geometrical parameters of the sample and the SQUID.

Original languageEnglish
Pages (from-to)1473-1479
Number of pages7
JournalPhysica C: Superconductivity and its applications
Issue numberSPEC. ISS.
Publication statusPublished - Oct 2004

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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