Magnetic nanocomposite of anti-human IgG/COOH-multiwalled carbon nanotubes/Fe3O4 as a platform for electrochemical immunoassay

Hajar Zarei, Hedayatollah Ghourchian, Khadijeh Eskandari, Majid Zeinali

Research output: Contribution to journalArticlepeer-review

63 Citations (Scopus)

Abstract

An electrochemical immunosensing method was developed based on a magnetic nanocomposite. The multiwalled carbon nanotubes (MWCNTs) were treated with nitric acid to produce carboxyl groups at the open ends. Then, Fe 3O4 nanoparticles were deposited on COOH-MWCNTs by chemical coprecipitation of Fe2+ and Fe3+ salts in an alkaline solution. Goat anti-human IgG (anti-hIgG) was covalently attached to magnetic nanocomposite through amide bond formation between the carboxylic groups of MWCNTs and the amine groups of anti-hIgG. The prepared bio-nanocomposite was used for electrochemical sensing of human tetanus IgG (hIgG) as a model antigen. The anti-hIgG magnetic nanocomposite was fixed on the surface of a gold plate electrode using a permanent magnet. The hIgG was detected using horseradish peroxidase (HRP)-conjugated anti-hIgG in a sandwich model. Electrochemical detection of hIgG was carried out in the presence of H2O2 and KI as substrates of HRP. Using this method, hIgG was detected in a concentration range from 30 to 1000 ng ml-1 with a correlation coefficient of 0.998 and a detection limit of 25 ng ml-1 (signal/noise = 3). The designed immunosensor was stable for 1 month.

Original languageEnglish
Pages (from-to)446-453
Number of pages8
JournalAnalytical Biochemistry
Volume421
Issue number2
DOIs
Publication statusPublished - 2012 Feb 15
Externally publishedYes

Keywords

  • Biosensor
  • Electrochemical immunoassay
  • Magnetic nanocomposite
  • Multiwalled carbon nanotubes
  • Sandwich model

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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