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Ag(I)-coordinated hairpin DNA for homogenous electronic monitoring of hepatitis C virus accompanying isothermal cycling signal amplification strategy

Lu, Minghua, Xu, Linfang, Zhang, Xiaona, Xiao, Rui, Wang, Youmei
Biosensors & bioelectronics 2015 v.73 pp. 195-201
DNA, Hepatitis C virus, biosensors, blood serum, carbon, dissociation, electrochemistry, electrodes, ions, monitoring, polymerization, silver
This work designs a new homogenous electronic monitoring platform for sensitive detection of hepatitis C virus (HCV) on an immobilization-free Ag(I)-assisted hairpin DNA through the cytosine–Ag+–cytosine coordination chemistry. The assay consists of target-induced Ag+ dissociation from hairpin DNA and an isothermal circular strand-displacement polymerization (ICSDP) reaction. Upon target analyte introduction, HCV DNA initially hybridizes with hairpin DNA to disrupt the Ag(I)-coordinated hairpin probe and releases the coordinated Ag+ ion, then the newly formed DNA duplex induces the ICSDP reaction with the aid of primer and polymerase, and then the displaced target DNA retriggers Ag(I)-coordinated hairpin DNA with target recycling, thereby resulting in formation of numerous free Ag+ ions in the detection cell. The released Ag+ ions can be readily captured by the negatively charged screen-printed carbon electrode, and subsequent anodic-stripping voltammetric detection of the captured Ag+ ions are conducted to form the anodic current for the production of the electrochemical signal within the applied potential. Under optimal conditions, the ICSDP-based homogenous sensing system can be utilized for the detection of HCV DNA at a concentration as low as 2.3pM. Intra- and inter-assay coefficients of variation with identical batches are below 9.5% and 10.5%, respectively. The analysis in 5 clinical serum specimens shows good accordance between results obtained by the developed method and commercial Cobas® Amplicor HCV Test Analyzer