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Updated: Apr 7, 2026
An Anaerobic Biosensor Assay for the Detection of Mercury and Cadmium
Published on: December 17, 2018
An electrochemical aptamer biosensor based on "gate-controlled" effect using β-cyclodextrin for ultra-sensitive
Jianping Li1, Mi Sun1, Xiaoping Wei1
1Guangxi Key Laboratory of Electrochemical and Magnetochemical Function Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China.
Abstract:
A new strategy for construction an electrochemical biosensor for Hg(2+) analysis with extremely high sensitivity was proposed based on "T-Hg(2+)-T" coordination by aptamers and "gate-controlled" amplification by switch of the channels of the probe. SH-β-cyclodextrin was self-assembled on the gold electrode to form an orderly arranged molecularly layer with interspaces among β-CDs; thionine labeled aptamer was then linked on the assembled β-CD. When Hg(2+) was added, the aptamer combined with Hg(2+) and formed "T-Hg(2+)-T" structure, which caused the aptamer folded and the labeled thionine covered the interspaces to block off the channel for probe entrance. The oxidative current of probe decreased, which provide the basis for the determination of Hg(2+). With the gate-controlled amplification, the changes of trace amounts of Hg(2+) will produce great changes of the probe current. The sensor exhibited significantly higher sensitivity with a detection limit of 5.0×10(-15) mol/L, which is lower than other reported methods.
