| 17477503 |
Miranda-Castro R, de-Los-Santos-Alvarez P, Lobo-Castanon MJ, Miranda-Ordieres AJ, Tunon-Blanco P: Hairpin-DNA probe for enzyme-amplified electrochemical detection of Legionella pneumophila. Anal Chem. 2007 Jun 1;79(11):4050-5. Epub 2007 May 4.
An electrochemical genosensor for the detection of nucleic acid sequences specific of Legionella pneumophila is reported. An immobilized thiolated hairpin probe is combined with a sandwich-type hybridization assay, using biotin as a tracer in the signaling probe, and streptavidin-alkaline phosphatase as reporter molecule. The activity of the immobilized enzyme was voltammetrically determined by measuring the amount of 1-naphthol generated after 2 min of enzymatic dephosphorylation of 1-naphthyl phosphate. The sensor allows discrimination between L. pneumophila and L. longbeachae with high sensitivity under identical assay conditions (no changes in stringency). A limit of detection of 340 pM L. pneumophila DNA, and a linear relationship between the analytical signal and the logarithm of the target concentration to 2 muM were obtained. Experimental results show the superior sensitivity and selectivity of the hairpin-based assay when compared with analogous sandwich-type assays using linear capture probes. |
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