A1 Refereed original research article in a scientific journal
Homogeneous quenching immunoassay for fumonisin B-1 based on gold nanoparticles and an epitope-mimicking yellow fluorescent protein
Authors: Peltomaa R, Amaro-Torres F, Carrasco S, Orellana G, Benito-Pena E, Moreno-Bondi MC
Publisher: AMER CHEMICAL SOC
Publication year: 2018
Journal:ACS Nano
Journal name in sourceACS NANO
Journal acronym: ACS NANO
Volume: 12
Issue: 11
First page : 11333
Last page: 11342
Number of pages: 10
ISSN: 1936-0851
DOI: https://doi.org/10.1021/acsnano.8b06094
Abstract
Homogeneous immunoassays represent an attractive alternative to traditional heterogeneous assays due to their simplicity, sensitivity, and speed. On the basis of a previously identified epitope-mimicking peptide, or mimotope, we developed a homogeneous fluorescence quenching immunoassay based on gold nanoparticles (AuNPs) and a recombinant epitope-mimicking fusion protein for the detection of mycotoxin fumonisin B-1 (FB1). The fumonisin mimotope was cloned as a fusion protein with a yellow fluorescent protein that could be used directly as the tracer for FB1 detection without the need of labeling or a secondary antibody. Furthermore, owing to the fluorescence quenching ability of AuNPs, a homogeneous immunoassay could be performed in a single step without washing steps to separate the unbound tracer. The homogeneous quenching assay showed negligible matrix effects in 5% wheat extract and high sensitivity for FB1 detection, with a dynamic range from 7.3 to 22.6 ng mL(-1), a detection limit of 1.1 ng mL(-1), and IC50 value of 12.9 ng mL(-1), which was significantly lower than the IC50 value of the previously reported assay using the synthetic counterpart of the same mimotope in a microarray format. The homogeneous assay was demonstrated to be specific for fumonisins B-1 and B-2, as no significant cross-reactivity with other mycotoxins was observed, and acceptable recoveries (86% for FB1 2000 mu g kg(-1) and 103% for FB1 4000 mu g kg(-1)), with relative standard deviation less than 6.5%, were reported from spiked wheat samples, proving that the method could provide a valuable tool for simple analysis of mycotoxin-contaminated food samples.
Homogeneous immunoassays represent an attractive alternative to traditional heterogeneous assays due to their simplicity, sensitivity, and speed. On the basis of a previously identified epitope-mimicking peptide, or mimotope, we developed a homogeneous fluorescence quenching immunoassay based on gold nanoparticles (AuNPs) and a recombinant epitope-mimicking fusion protein for the detection of mycotoxin fumonisin B-1 (FB1). The fumonisin mimotope was cloned as a fusion protein with a yellow fluorescent protein that could be used directly as the tracer for FB1 detection without the need of labeling or a secondary antibody. Furthermore, owing to the fluorescence quenching ability of AuNPs, a homogeneous immunoassay could be performed in a single step without washing steps to separate the unbound tracer. The homogeneous quenching assay showed negligible matrix effects in 5% wheat extract and high sensitivity for FB1 detection, with a dynamic range from 7.3 to 22.6 ng mL(-1), a detection limit of 1.1 ng mL(-1), and IC50 value of 12.9 ng mL(-1), which was significantly lower than the IC50 value of the previously reported assay using the synthetic counterpart of the same mimotope in a microarray format. The homogeneous assay was demonstrated to be specific for fumonisins B-1 and B-2, as no significant cross-reactivity with other mycotoxins was observed, and acceptable recoveries (86% for FB1 2000 mu g kg(-1) and 103% for FB1 4000 mu g kg(-1)), with relative standard deviation less than 6.5%, were reported from spiked wheat samples, proving that the method could provide a valuable tool for simple analysis of mycotoxin-contaminated food samples.
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