An electrochemical genosensing assay based on magnetic beads and gold nanoparticle-loaded latex microspheres for vibrio cholerae detection
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Author list: Low K.-F., Rijiravanich P., Singh K.K.B., Surareungchai W., Yean C.Y.
Publisher: American Scientific Publishers
Publication year: 2015
Volume number: 11
Issue number: 4
Start page: 702
End page: 710
Number of pages: 9
ISSN: 1550-7033
eISSN: 1550-7033
Languages: English-Great Britain (EN-GB)
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Abstract
An ultrasensitive electrochemical genosensing assay was developed for the sequence-specific detection of Vibrio cholerae DNA using magnetic beads as the biorecognition surface and gold nanoparticle-loaded latex microspheres (latex-AuNPs) as a signal-amplified hybridization tag. This biorecognition surface was prepared by immobilizing specific biotinylated capturing probes onto the streptavidin-coupled magnetic beads. Fabricating a hybridization tag capable of amplifying the electrochemical signal involved loading multiple AuNPs onto polyelectrolyte multilayer film-coated poly(styrene-co-acrylic acid) latex microspheres as carrier particles. The detection targets, single-stranded 224-bp asymmetric PCR amplicons of the V. cholerae lolB gene, were sandwich-hybridized to magnetic bead-functionalized capturing probes and fluoresceinlabeled detection probes and tagged with latex-AuNPs. The subsequent electrochemical stripping analysis of chemically dissolved AuNPs loaded onto the latex microspheres allowed for the quantification of the target amplicons. The highloading capacity of the AuNPs on the latex microspheres for sandwich-type dual-hybridization genosensing provided eminent signal amplification. The genosensing variables were optimized, and the assay specificity was demonstrated. The clinical applicability of the assay was evaluated using spiked stool specimens. The current signal responded linearly to the different V. cholerae concentrations spiked into stool specimens with a detection limit of 2 colony-forming units (CFU)/ml. The proposed latex-AuNP-based magnetogenosensing platform is promising, exhibits an effective amplification performance, and offers new opportunities for the ultrasensitive detection of other microbial pathogens.
Keywords
Magnetic bead, signal amplification
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