title: Disposable electrochemical genosensor for the simultaneous analysis of different bacterial food contaminants.
abstract: This paper deals with the use of an electrochemical genosensor array for the rapid and simultaneous detection of different food-contaminating pathogenic bacteria. The method includes PCR amplification followed by analysis of the amplicons by hybridisation with toxin-specific oligonucleotide probes. A screen-printed array of four gold electrodes, modified using thiol-tethered oligonucleotide probes, was used. Unmodified PCR products were captured at the sensor interface via sandwich hybridisation with surface-tethered probes and biotinylated signaling probes. The resulting biotinylated hybrids were coupled with a streptavidin-alkaline phosphatase conjugate and then exposed to an alpha-naphthyl phosphate solution. Differential pulse voltammetry was finally used to detect the alpha-naphthol oxidation signal. Mixtures of DNA samples from different bacteria were detected at the nanomolar level without any cross-interference. The selectivity of the assay was also confirmed by the analysis of PCR products unrelated to the immobilised probes.
authors.affiliation: Dipartimento di Chimica, Università Degli Studi di Firenze, Via Della Lastruccia 3, 50019 Sesto Fiorentino (Fi), Italy.
authors.forename: F
authors.initials: F
authors.lastname: Farabullini
authors.forename: F
authors.initials: F
authors.lastname: Lucarelli
authors.forename: I
authors.initials: I
authors.lastname: Palchetti
authors.forename: G
authors.initials: G
authors.lastname: Marrazza
authors.forename: M
authors.initials: M
authors.lastname: Mascini
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation*; D004563:Electrochemistry / Q000295:instrumentation*; D004926:Escherichia coli / Q000235:genetics; D019453:Escherichia coli O157 / Q000235:genetics; D005516:Food Microbiology; D008089:Listeria monocytogenes / Q000235:genetics; D008969:Molecular Sequence Data; D012475:Salmonella / Q000235:genetics / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000235:genetics