科研之友
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摘要
A sensitive and cost-effective method for the simultaneous quantitation of trace ambunts of Hg2+ and Pb2+ in rear-world samples has been developed using., DNA molecular beacon probes bound to bona fide digital video discs (DVDs). With specially designed T-rich or G-rich loon sequences, the detection is based on the strong T-Hg2+-T coordination chemistry of He and. the formation of G-quadruplexes induced by Pb2+, respectively. In particular:the presence of metal cations leads to,hairpin opening and exposure of the terminal biotin moiety for binding nanogold-streptavidin conjugates. The recognition signal was subsequently enhanced by gold nanoparticle-promoted silver deposition, which leads to quantifiable digital signals upon reading with a standard computer drive. This method exhibits a wide response range and-low detection limits for both Hg2+ and. Pb2+. In addition, the quantitative determination of heavy metals in food products' (e.g., rice samples) has been demonstrated and: the method compares favorably with other optical sensors developed recently.
