Ministry of Education & Fujian Provincial Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou 350108, PR China.
Biosens Bioelectron. 2013 Jan 15;39(1):315-9. doi: 10.1016/j.bios.2012.07.015. Epub 2012 Jul 20.
A simple, sensitive and reusable electrochemical sensor was designed for determination of mercury (II) (Hg(2+)) by coupling target-induced conformational switch of DNA hairpins with thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry. The hairpin probe consisted of a stem of 6 base pairs enclosing a 14 nucleotide (nt) loop and an additional 12 nt sticky end at the 3' end. Each hairpin was labeled with ferrocene (Fc) redox tag in the middle of the loop, which was immobilized on the electrode via self-assembly of the terminal thiol moiety at the 5' end. In the presence of target analyte, Hg(2+)-mediated base pairs induced the conformational change from the sticky end to open the hairpins, resulting in the ferrocene tags close to the electrode for the increasing redox current. The strong coordination reaction of T-Hg(2+)-T resulted in a good repeatability and intermediate precision down to 10%. The dynamic concentration range spanned from 5.0nM to 1.0μM Hg(2+) with a detection limit of 2.5nM at the 3s(blank) level. The strategy afforded exquisite selectivity for Hg(2+) against other environmentally related metal ions. Inspiringly, the developed sensor could be reused by introduction of iodide (I(-)).
设计了一种简单、灵敏且可重复使用的电化学传感器，用于通过 DNA 发夹的靶标诱导构象开关与胸腺嘧啶-汞(II)-胸腺嘧啶（T-Hg(II)-T）配位化学相结合来测定汞(II)（Hg(II)）。发夹探针由 6 个碱基对的茎组成，包含一个 14 个核苷酸（nt）的环和 3' 端额外的 12 个 nt 粘性末端。每个发夹在环的中间标记有二茂铁（Fc）氧化还原标记物，通过 5' 端末端硫醇部分的自组装固定在电极上。在存在目标分析物的情况下，Hg(II)介导的碱基对诱导从粘性末端到发夹打开的构象变化，导致 Fc 标记物靠近电极以增加氧化还原电流。T-Hg(II)-T 的强配位反应导致良好的重复性和中间精度，低至 10%。动态浓度范围从 5.0 nM 到 1.0 μM Hg(II)，检测限为 2.5 nM（空白 3s 水平）。该策略提供了对 Hg(II)的出色选择性，不受其他环境相关金属离子的影响。令人鼓舞的是，通过引入碘化物（I(-)），开发的传感器可以重复使用。
