【摘 要】
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In this study,a novel multiple amplified electrochemical immunosensor was designed for highly efficient detection of microcystin–LR by using the dendritic Au nanostructures as the substrate,and mesopo
【机 构】
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College of Materials and Energy,South China Agricultural University,Guangzhou,China
【出 处】
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2016年分析化学前沿国际研讨会及中美分析化学研讨会
论文部分内容阅读
In this study,a novel multiple amplified electrochemical immunosensor was designed for highly efficient detection of microcystin–LR by using the dendritic Au nanostructures as the substrate,and mesoporous silica-functionalized DNAzyme concatamers with redox-active intercalators as the label carrier.First,the dendritic Au nanostructures were in-situ electrodeposited on the surface of indium tin oxide(ITO)electrode with the aid of L-cysteine.On account of their huge specific surface area,numerous antigens can be immobilized to the electrode surface by non-covalent bonding.Second,silica/mesoporous silica core–shell nanocomposites(SiO2@MSN)with excellent monodispersity and uniform pore diameter was synthesized to conjugate the second antibody(Ab2)and initiator strands(S0)on its surface and fill the redox indicator(Methylene blue,MB)in its open mesopores.In order to achieve the amplification of the detection signal,two auxiliary DNA strands(S1 and S2)were designed for the in-situ propagation with S0 to form a double-helix DNA on the surface of SiO2@MSN through hybridization chain reaction(HCR).After adding the hemin,numerous DNAzymes(G-quadruplex/hemin)were formed on each side of double-helix DNA.Meanwhile,a number of methylene blue molecules can be intercalated into the grooves of the double-helix DNA.The DNAzymes can catalyze the reduction of H2O2 to yield electrochemical signals with the help of methylene blue embedded in pores of SiO2@MSN and the grooves of the double-helix DNA.By taking the advantages of DNA amplification techniques,high sensitivity of electrochemical detection and surface effect of nanomaterials,the proposed electrochemical immunoassay exhibited a wide detection range of 1 μg/L~0.005 μg/L toward MC-LR standards with a low detection limit of 9.2107×10-5 μg/L.
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