title: Ultrasensitive electrochemical detection of DNA based on Zn²⁺ assistant DNA recycling followed with hybridization chain reaction dual amplification.
abstract: A new strategy to combine Zn(2+) assistant DNA recycling followed with hybridization chain reaction dual amplification was designed for highly sensitive electrochemical detection of target DNA. A gold electrode was used to immobilize molecular beacon (MB) as the recognition probe and perform the amplification procedure. In the presence of the target DNA, the hairpin probe 1 was opened, and the DNAzyme was liberated from the caged structure. The activated DNAzyme hybridized with the MB and catalyzed its cleavage in the presence of Zn(2+) cofactor and resulting in a free DNAzyme strand. Finally, each target-induced activated DNAzyme underwent many cycles triggering the cleavage of MB, thus forming numerous MB fragments. The MB fragments triggered the HCR and formed a long double-helix DNA structure. Because both H1 and H2 were labeled by biotin, a lot of SA-ALP was captured on the electrode surface, thus catalyzing a silver deposition process for electrochemical stripping analysis. This novel cascade signal amplification strategy can detect target DNA down to the attomolar level with a dynamic range spanning 6 orders of magnitude. This highly sensitive and specific assay has a great potential to become a promising DNA quantification method in biomedical research and clinical diagnosis.
authors.affiliation: Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 344000, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Qian
authors.affiliation: Key Laboratory of Radioactive Geology and Exploration Technology Fundamental Science for National Defense, East China Institute of Technology, Nanchang 344000, China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Wang
authors.affiliation: Jiangsu Key Laboratory of Target Drug and Clinical Application, School of Pharmacy, Xuzhou Medical College, Xuzhou 221004, China. Electronic address: jsxzgfl@sina.com.
authors.forename: Fenglei
authors.initials: F
authors.lastname: Gao
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification*; D021881:DNA, Catalytic / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D006046:Gold / Q000737:chemistry; D006801:Humans; D009693:Nucleic Acid Hybridization; D012834:Silver / Q000737:chemistry
chemical_list: D021881:DNA, Catalytic; D012834:Silver; D006046:Gold; D004247:DNA
keywords: Electrochemical; Hybridization chain reaction; Signal amplification; Silver nanoparticles