An electrochemical Hg2+ sensor based on signal amplification strategy of target recycling

• Published in: Talanta (Oxford) 2021-02, Vol.223, p.121709-121709, Article 121709
• Main Authors: Zhong, You quan, Ning, Tian jiao, Cheng, Lin, Xiong, Wei, Wei, Guo bing, Liao, Fu sheng, Ma, Guang qiang, Hong, Nian, Cui, Han feng, Fan, Hao
• Format: Article
• Language: English
• Subjects: Au–S self-Assembly; Catalytic hairpin assembly; Homogeneous solution; Tetraferrocene
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2020.121709

In this work, an unmodified homogeneous electrochemical sensor based on electrochemical bonding and catalytic hairpin assembly (CHA) was first constructed for the high sensitivity detection of Hg2+. Herein, tetraferrocene, a synthesized compound, was used as a signal marker that modified both ends of the hairpin probe to amplify the electrochemical signal. The interaction of T-Hg2+-T could induce the catalytic self-assembly of hairpins by means of auxiliary DNA. The rigid DNA triangle that was formed easily reaches the electrode and induced Au–S self-assembly assisted by potential, allowing tetraferrocene to reach the electrode surface and generate a sensitive electrochemical signal. CHA and tetraferrocene signal markers accomplished dual signal amplification, and the limit of detection was 0.12 pM. Differential pulse voltammetry experiments in the presence of tetraferrocene redox indicator show that the linear response range of electrochemical biosensors to mercury ions is 0.2–2000 pM, This technology offers good selectivity and high recognition efficiency for the detection of mercury ions and has broad application prospects in actual sample detection. Schematic diagram of the electrochemical Hg2+ sensor operation. The probe and the target induce the hairpin to catalyze self-assembly to form a rigid DNA triangular structure with the help of auxiliary DNA. A higher signal was generated when tetraferrocene reached the electrode. the electrochemical signals were determined by differential voltammetric pulses (DPV). [Display omitted] •3, 5-bis (3, 5-bisferrocenethoxybenzyloxy) benzoic acid was first synthesized for electrochemical Hg2+ sensor based on catalytic hairpin self-assembly.•Sensitive and homogeneous biosensor based on electrochemical bonding between tetraferrocene and electrode surface was successfully applied to in traditional Chinese medicine with detection limit reaching 0.12 pM.•Since there is no need to modify the electrode surface with complicated materials, it saves a lot of time for the whole work, avoids reagent loss, and saves time and cost.•Catalytic hairpin self-assembly occurs in a homogeneous solution, avoiding steric hindrance effects and improving detection efficiency.