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Updated: Apr 14, 2026
An Anaerobic Biosensor Assay for the Detection of Mercury and Cadmium
Published on: December 17, 2018
A regenerative electrochemical biosensor for mercury(II) by using the insertion approach and dual-hairpin-based
Jing Jia1, Yu Ling1, Zhong Feng Gao1
1Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
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.
