RESUMEN
This work addresses a technological advance applied to the construction of a magnetogenoassay with electrochemical transduction for the maize taxon-specific (HMGA gene) detection using gold-coated magnetic nanoparticles as nanosized platform. Superparamagnetic core-shell Fe3O4@Au nanoparticles (10.4⯱â¯1.7â¯nm) were used to assemble the genoassay through the covalent immobilization of HMGA DNA probes onto carboxylated self-assembled monolayers at the nanoparticles surface. A hybridization reaction using sandwich format was selected to prevent inefficient hybridization connected with stable secondary DNA structures using also fluorescein isothiocyanate as DNA signaling tag. The labelling of the hybridization reaction with enzymes allowed the chronoamperometric measurement of the peroxidase activity linked to the nanoplatform located on gold surface. Using this electrochemical magnetogenoassay a linear concentration range from 0.5 to 5â¯nM and a LOD of 90 pM with a RSD <1.2% was calculated. Certified maize was evaluated without further purification after PCR amplification. This work highlights the efficacy of the electrochemical magnetogenoassay for the HMGA detection, showing its potential as alternative procedure for the verification of the compliance of the legislation.
Asunto(s)
Técnicas Biosensibles/métodos , Genes de Plantas , Oro/química , Proteínas HMGA/genética , Nanopartículas de Magnetita/química , Zea mays/genética , Secuencia de Bases , Sondas de ADN/química , Sondas de ADN/genética , ADN de Plantas/química , ADN de Plantas/genética , ADN de Cadena Simple/química , ADN de Cadena Simple/genética , Técnicas Electroquímicas/métodos , Ácidos Nucleicos Inmovilizados/química , Ácidos Nucleicos Inmovilizados/genética , Límite de Detección , Hibridación de Ácido Nucleico , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente/genéticaRESUMEN
An on-surface isothermal helicase-dependent amplification is devised for simple, point-of-need quantification of bacterial genomes. The method relies on the enzyme-extension of a thiol-modified reverse primer anchored to indium tin oxide electrodes, which shows strikingly high thermal and storage stability. Amplification and electrochemical detection of only 10 genomes are thus performed on the same platform without thermal cycling.