Development of a membrane strip immunosensor utilizing ruthenium as an electro-chemiluminescent signal generator

Chae H. Yoon, Joung Hwan Cho, Heung I. Oh, Ja Kim Min, Chi W. Lee, Jeong W. Choi, Se Hwan Paek

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

A photometric immunosensor that can be used for on-site diagnosis has been constructed. The sensor system was assembled by partially superimposing a nitrocellulose membrane strip (the lower) containing an immobilized antigen on the surface with a glass fiber membrane strip (the upper) including two electrodes on the opposite surfaces. To amplify the signal, we introduced a liposome, containing ruthenium molecules trapped in the core, chemically coupled to an antibody specific to the analyte (e.g. Legionella antigen). In the presence of the analyte, immune complexes were formed by antigen-antibody reactions upon addition of the immuno-liposome into a sample. This mixture was then absorbed by the capillary action from the bottom of the membrane strip. The liposome particles in the complexes were carried by a medium through the antigen pad without interaction, while free immuno-liposome was trapped by immune reactions on the pad surfaces. The aqueous medium influx into the glass pad dissolved a detergent pre-located within the compartment and the liposome rupture thereby released ruthenium molecules into the solution. The molecules were oxidized on the electrode surfaces and produced an electro- chemiluminescence (ECL) in proportion to the analyte concentration. The signal generation based on ECL resulted in an exponential dose-response pattern and the analyte detection limit of 2 ng/ml was approximately 10-fold more sensitive than that obtained from a conventional system.

Original languageEnglish
Pages (from-to)289-296
Number of pages8
JournalBiosensors and Bioelectronics
Volume19
Issue number4
DOIs
Publication statusPublished - 2003 Dec 15

Keywords

  • Electro-chemiluminescence
  • Immuno-chromatographic assay
  • Immuno-liposome
  • Point-of-care device
  • Screen-printed electrodes

ASJC Scopus subject areas

  • Biotechnology
  • Analytical Chemistry
  • Electrochemistry

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