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.
Bibliographical noteFunding 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.
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.
© 2021 Elsevier B.V.
- Functionalised ferromagnetic gold nanoparticles
- Monoclonal antibodies
- Mycobacterium bovis
- Mycobacterium tuberculosis complex differentiation
ASJC Scopus subject areas
- Analytical Chemistry
- Environmental Chemistry
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Development and evaluation of nanoparticle-based immunoassays for TB detection and speciation of Mycobacterium tuberculosis and Mycobacterium bovisAuthor: Gilbride, B., Jul 2022
Student thesis: Doctoral Thesis › Doctor of Philosophy