title: A regenerative electrochemical biosensor for mercury(II) by using the insertion approach and dual-hairpin-based amplification.
abstract: A simple and effective biosensor for Hg(2+) determination was investigated. The novel biosensor was prepared by the insertion approach that the moiety-labeled DNA inserted into a loosely packed cyclic-dithiothreitol (DTT) monolayer, improving the hybridization efficiency. Electrochemical impedance spectroscopy studies of two biosensors (single-hairpin and dual-hairpin structure DNA modified electrodes) used for Hg(2+) detection indicated that the dual-hairpin modified electrode had a larger electron transfer resistance change (ΔRct). Consequently, the dual-hairpin structure was used as a signal amplifier for the preparation of a selective Hg(2+) biosensor. This biosensor exhibited an excellent selectivity toward Hg(2+) over Cd(2+), Pd(2+), Co(2+) etc. Also, a linear relation was observed between the ΔRct and Hg(2+) concentrations in a range from 0.1 nM to 5 μM with a detection limit of 28 pM under optimum conditions. Moreover, the biosensor can be reused by using L-cysteine and successfully applied for detecting Hg(2+) in real samples.
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Jia
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ling
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
authors.forename: Zhong Feng
authors.initials: ZF
authors.lastname: Gao
authors.affiliation: College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, PR China.
authors.forename: Jing Lei
authors.initials: JL
authors.lastname: Lei
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: luohq@swu.edu.cn.
authors.forename: Hong Qun
authors.initials: HQ
authors.lastname: Luo
authors.affiliation: Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: linb@swu.edu.cn.
authors.forename: Nian Bing
authors.initials: NB
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004229:Dithiothreitol; D004566:Electrodes; D008628:Mercury / Q000032:analysis*; D021141:Nucleic Acid Amplification Techniques
chemical_list: D008628:Mercury; D004229:Dithiothreitol
keywords: Dual hairpin; Electrochemical impedance spectra; Insertion approach; Label free; Regeneration