title: Novel homogeneous label-free electrochemical aptasensor based on functional DNA hairpin for target detection.
abstract: We first developed a label-free and immobilization-free homogeneous electrochemical aptasensor, which combined a smart functional DNA hairpin and a designed miniaturized electrochemical device. Cocaine was chosen as a model target. The anticocaine aptamer and peroxidase-mimicking DNAzyme were integrated into one single-stranded DNA hairpin. Both aptamer and G-quadruplex were elaborately blocked by the stem region. The conformation switching induced by the affinity interaction between aptamer and cocaine released G-quadruplex part and turned on DNAzyme activity. The designed electrochemical device, constructed by a disposable micropipet tip and a reproducible carbon fiber ultramicroelectrode, was applied to the detection of homogeneous DNAzyme catalytic activity at the microliter level. The aptasensor realized the quantification of cocaine ranging from 1 to 500 μM with high specificity. The clever combination of the functional DNA hairpin and the novel device achieved an absolutely label-free electrochemical aptasensor, which showed excellent performance like low cost, easy operation, rapid detection, and high repeatability.
authors.affiliation: Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University , Beijing 100871, China.
authors.forename: De-Wen
authors.initials: DW
authors.lastname: Zhang
authors.forename: Ji
authors.initials: J
authors.lastname: Nie
authors.forename: Fang-Ting
authors.initials: FT
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Ying-Lin
authors.initials: YL
authors.lastname: Zhou
authors.forename: Xin-Xiang
authors.initials: XX
authors.lastname: Zhang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism; D003042:Cocaine / Q000032:analysis* / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D021881:DNA, Catalytic / Q000737:chemistry / Q000378:metabolism; D055664:Electrochemical Techniques / Q000379:methods*; D004789:Enzyme Activation; D054856:G-Quadruplexes
chemical_list: D052157:Aptamers, Nucleotide; D021881:DNA, Catalytic; D004247:DNA; D003042:Cocaine