Clara Pereira - Highly Monodisperse Fe3O4@Au Superparamagnetic Nanoparticles as Reproducible Platform for Genosensing Genetically Modified Organisms

Document created by Clara Pereira on Aug 29, 2016Last modified by Clara Pereira on Oct 26, 2016
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  “Highly Monodisperse Fe3O4@Au Superparamagnetic Nanoparticles as Reproducible Platform for Genosensing Genetically Modified Organisms”, Maria Freitas, Maria Sá Couto, Maria Fátima Barroso, Clara Pereira, Noemí de-los-Santos-Álvarez, Arturo J. Miranda-Ordieres, María Jesús Lobo-Castañón, Cristina Delerue-Matos, ACS Sensors 2016, 1, 1044−1053. DOI: 10.1021/acssensors.6b00182


  Several routes have been developed to prepare magnetic core–shell   Fe3O4@Au nanoparticles (MNPs). However,   only highly monodisperse MNPs are suitable for analytical   applications. Herein, we describe the detection of GMO through   the use of gold-coated MNPs with fine-tuned properties as   platforms. The MNPs were prepared through a procedure that   involves the preparation of Fe3O4 cores by   thermal decomposition and their coating through reduction of a   gold precursor. Different Fe3O4:Au   precursor molar ratios (1:1; 1:4; 1:7) were tested on the   Fe3O4 encapsulation. Monodisperse   quasi-spherical core–shell Fe3O4@Au were   obtained for the 1:4 and 1:7 ratios, in contrast, the 1:1 ratio   did not lead to complete encapsulation of   Fe3O4 cores. Therefore, the   Fe3O4@Au obtained from higher   Fe3O4:HAuCl4 ratios were tested   as platforms for an electrochemical genoassay to detect MON810.   The best performance was achieved with the   Fe3O4@Au prepared from 1:4 ratio (10.0 ±   1.7 nm). A DNA probe covalently linked to a carboxylated   self-assembled monolayer and a fluorescein isothiocyanate (FITC)   signaling probe were used in a sandwich assay format. Labeling   with anti-FITC-peroxidase Fab fragment conjugate allowed   chronoamperometric measurements of the enzyme activity captured   on Fe3O4@Au placed on screen-printed   electrodes upon the hybridization event. The genoassay provided a   linear range from 0.25 to 2.5 nM, LOD of 0.15 nM, with a   reproducibility <4%. Certified samples containing the   transgenic event were measured without further purification after   PCR amplification. The results highlight the efficiency of the   genoassay for the MON810 detection, opening new horizons to   achieve a low-cost analysis out of large laboratory facilities to   verify the compliance of GMO regulations.

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