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Label‐Free Detection of MicroRNA: Two‐Step Signal Enhancement with a Hairpin‐Probe‐Based Graphene Fluorescence Switch and Isothermal Amplification
Author(s) -
Zhu Xiao,
Zhou Xiaoming,
Xing Da
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201204605
Subject(s) - loop mediated isothermal amplification , fluorescence , intercalation (chemistry) , graphene , bioanalysis , polymerization , signal (programming language) , molecular beacon , nanotechnology , dna , chemistry , combinatorial chemistry , biophysics , nucleic acid , rolling circle replication , materials science , oligonucleotide , polymerase , computer science , biochemistry , polymer , organic chemistry , biology , physics , quantum mechanics , programming language
A label‐free approach with multiple enhancement of the signal for microRNA detection has been introduced. The key idea of this strategy is achieved by taking advantage of a novel graphene oxide (GO)/intercalating dye based fluorescent hairpin probe (HP) and an isothermal polymerization reaction. In this paper, we used microRNA‐21 (mir‐21) as the target to examine the desirable properties of this assay. When the target, as a “trigger”, was hybridized with the HP and caused a conformation change, an efficient isothermal polymerization reaction was activated to achieve the first step of the “signal” amplification. After incubation with the platform of GO/intercalating dye, the formed complex of DNA interacted with the high‐affinity dye and then detached from the surface of the GO, a process that was accompanied by distinguishable fluorescence recovery. Further signal enhancement has been accomplished by a mass of intercalating dye inserting into the minor groove of the long duplex replication product. Due to the efficient and multiple amplification steps, this approach exerted a substantial enhancement in sensitivity and could be used for rapid and selective detection of Mir‐21 at attomole levels. Proof‐of‐concept evidence has been provided for the proposed cost‐effective strategy; thus, this strategy could expand the application of GO‐material‐based bioanalysis for nucleic acid studies.