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Issue 35, 2018
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Highly sensitive colorimetric immunoassay for Escherichia coli O157:H7 based on probe of pseudo enzyme and dual signal amplification

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Abstract

Here we developed a highly sensitive colorimetric immunoassay for the detection of Escherichia coli O157:H7 (E. coli O157:H7). Fe3O4 nanoparticles coated with carboxyl groups were synthesized by a one-pot method and modified with E. coli O157:H7 antiserum as capture probes. Au@Pt nanoparticles with peroxidase-like activity were combined with flaky reduced graphene oxide-neutral red (rGO-NR) to form chromogenic probes of pseudo enzyme. To increase the sensitivity, bovine serum albumin was replaced by horseradish peroxidase (HRP) as blocking protein of immune rGO-NR–Au@Pt. Meanwhile, HRP and Au@Pt constitute a dual signal amplification system. In the presence of E. coli O157:H7, the capture probes and chromogenic probes formed sandwich structures. The complexes were used to catalytically oxidize the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine and the absorbance at 450 nm is related to the concentration of bacteria. Although the feasibility is demonstrated using E. coli O157:H7 as a model analyte, this approach can be easily developed to be a universal analysis system and applied to detection of a wide variety of foodborne pathogens and protein biomarkers. This study proposed a point-of-care and convenient quantitative detection method for clinical diagnostics and food safety analysis.

Graphical abstract: Highly sensitive colorimetric immunoassay for Escherichia coli O157:H7 based on probe of pseudo enzyme and dual signal amplification

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Publication details

The article was received on 26 Jun 2018, accepted on 04 Aug 2018 and first published on 06 Aug 2018


Article type: Paper
DOI: 10.1039/C8AY01410H
Citation: Anal. Methods, 2018,10, 4301-4309
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    Highly sensitive colorimetric immunoassay for Escherichia coli O157:H7 based on probe of pseudo enzyme and dual signal amplification

    H. Huang, Z. Wu, J. Huang, G. Zhao and W. Dou, Anal. Methods, 2018, 10, 4301
    DOI: 10.1039/C8AY01410H

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