A surface plasmon resonance immunosensor for detecting a dioxin precursor using a gold binding polypeptide

Nobuaki Soh, Tomoyuki Tokuda, Tomomi Watanabe, Keiko Mishima, Toshihiko Imato, Takashi Masadome, Yasukazu Asano, Saeko Okutani, Osamu Niwa, Stanley Brown

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66 Citations (Scopus)

Abstract

A surface plasmon resonance (SPR) based biosensor was developed for monitoring 2,4-dichlorophenol, a known dioxin precursor, using an indirect competitive immunoassay. The SPR sensor was fabricated by immobilizing a gold-thin layer on the surface of an SPR sensor chip with an anti-(2,4-dichlorophenol) antibody using a gold binding polypeptide (GBP) and protein G. The SPR response based on the antigen-antibody reaction in a flow system was measured by injecting a 2,4-dichlorophenol sample solution into the flow system in which the SPR sensor was located. In a direct immunoassay system using the modified sensor chip, no significant SPR angle shift less than 0.001° was observed when a 25 ppm of 2,4-dichlorophenol solution was injected. In order to improve the sensitivity of the SPR sensor, an indirect competitive immunoassay method was used in conjunction with the SPR sensor system using 2,4-dichlorophenol conjugated with bovine serum albumin (BSA). In the competitive assay, a 350 ppm 2,4-dichlorophenol-BSA conjugate solution containing 2,4-dichlorophenol at various concentrations (10-250 ppb) were injected into the SPR sensor system. The sensitivity of this indirect immunoassay was found to be extremely sensitive, compared to the direct one, and a detection limit of 20 ppb was estimated. Verification that the use of GBP for immobilizing the antibody on the sensor chip enhanced the sensitivity to 2,4-dichlorophenol was obtained by comparing the procedure with another modification, in which BSA was used instead of GBP for immobilizing the antibody on the sensor chip. The affinity constant of 2,4-dichlorophenol and its conjugate to the antibody were estimated form the SPR response.

Original languageEnglish
Pages (from-to)733-745
Number of pages13
JournalTalanta
Volume60
Issue number4
DOIs
Publication statusPublished - 2003 Jul 4
Externally publishedYes

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Keywords

  • 2,4-Dichlorophenol
  • Dioxins
  • Endocrine disrupting chemicals
  • Gold binding polypeptide
  • Protein G
  • SPR sensor

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy

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