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search.filters.applied.f.access: openAccess × Author: Cialla-May, Dana × Author: Popp, Jürgen × Type: Text × Subject: Silver ×

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    Label-free detection of Phytophthora ramorum using surface-enhanced Raman spectroscopy
    (Cambridge : Soc., 2015) Yüksel, Sezin; Schwenkbier, Lydia; Pollok, Sibyll; Weber, Karina; Cialla-May, Dana; Popp, Jürgen
    In this study, we report on a novel approach for the label-free and species-specific detection of the plant pathogen Phytophthora ramorum from real samples using surface enhanced Raman scattering (SERS). In this context, we consider the entire analysis chain including sample preparation, DNA isolation, amplification and hybridization on SERS substrate-immobilized adenine-free capture probes. Thus, the SERS-based detection of target DNA is verified by the strong spectral feature of adenine which indicates the presence of hybridized target DNA. This property was realized by replacing adenine moieties in the species-specific capture probes with 2-aminopurine. In the case of the matching capture and target sequence, the characteristic adenine peak serves as an indicator for specific DNA hybridization. Altogether, this is the first assay demonstrating the detection of a plant pathogen from an infected plant material by label-free SERS employing DNA hybridization on planar SERS substrates consisting of silver nanoparticles.
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    Towards on-site testing of Phytophthora species
    (Cambridge : RSC Publ., 2014) Schwenkbier, Lydia; Pollok, Sibyll; König, Stephan; Urban, Matthias; Werres, Sabine; Cialla-May, Dana; Weber, Karina; Popp, Jürgen
    Rapid detection and accurate identification of plant pathogens in the field is an ongoing challenge. In this study, we report for the first time on the development of a helicase-dependent isothermal amplification (HDA) in combination with on-chip hybridization for the detection of selected Phytophthora species. The HDA approach allows efficient amplification of the yeast GTP-binding protein (Ypt1) target gene region at one constant temperature in a miniaturized heating device. The assay's specificity was determined by on-chip DNA hybridization and subsequent silver nanoparticle deposition. The silver deposits serve as stable endpoint signals that enable the visual as well as the electrical readout. Our promising results point to the direction of a near future on-site application of the combined techniques for a reliable detection of Phytophthora species.