Catalytic ferromagnetic gold nanoparticle immunoassay for the detection and differentiation of Mycobacterium tuberculosis and Mycobacterium bovis

Brendan Gilbride, Gustavo Marçal Schmidt Garcia Moreira, Michael Hust, Cuong Cao, Linda Stewart*

*Corresponding author for this work

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Abstract

A ferromagnetic gold nanoparticle based immune detection assay, exploiting the enhanced signal amplification of inorganic nanozymes, was developed and evaluated for its potential application in the detection of Mycobacterium tuberculosis complex (MTBC) organisms, and simultaneous identification of Mycobacterium bovis. Ferromagnetic gold nanoparticles (Au–Fe3O4 NPs) were prepared and their intrinsic peroxidase-like activity exploited to catalyse 3,3′,5’,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). When the Au–Fe3O4 NPs were functionalised by direct coupling with MTBC-selective antibodies, a nanoparticle based immune detection assay (NPIDA) was developed which could detect Mycobacterium tuberculosis (MTB) and differentiate M. bovis. In the assay, the intrinsic magnetic capability of the functionalised Au–Fe3O4 NPs was used in sample preparation to capture target bacterial cells. These were incorporated into a novel immunoassay which used species selective monoclonal antibodies (mAb) to detect bound target. The formation of a blue TMB oxidation product, with a peak absorbance of 370 nm, indicated successful capture and identification of the target. The detection limit of the NPIDA for both MTB and M. bovis was determined to be comparable to conventional ELISA using the same antibodies. Although limited matrix effects were observed in either assay, the NPIDA offers a reduced time to confirmatory identification. This novel NPIDA was capable of simultaneous sample concentration, purification, immunological detection and speciation. To our knowledge, it represents the first immune-based diagnostic test capable of identifying MTBC organisms and simultaneously differentiating M. bovis.

Original languageEnglish
Article number339037
JournalAnalytica Chimica Acta
Volume1184
Early online date13 Sep 2021
DOIs
Publication statusPublished - 01 Nov 2021

Bibliographical note

Funding Information:
The authors B.G., C.C. and L.S. acknowledge funding from the PhD studentship support fund from the Department for the Economy for Northern Ireland (DfE). We would wish to thank Agri-Food and Biosciences Institute for Northern Ireland for providing access to one of the antibodies evaluated as part of this study.

Funding Information:
The authors B.G. C.C. and L.S. acknowledge funding from the PhD studentship support fund from the Department for the Economy for Northern Ireland (DfE). We would wish to thank Agri-Food and Biosciences Institute for Northern Ireland for providing access to one of the antibodies evaluated as part of this study.

Publisher Copyright:
© 2021 Elsevier B.V.

Keywords

  • Functionalised ferromagnetic gold nanoparticles
  • Immuno-biosensor
  • Monoclonal antibodies
  • Mycobacterium bovis
  • Mycobacterium tuberculosis complex differentiation
  • Peroxidase-mimic

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

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