Electrochemiluminescence Detection of Silver Ion Based on Trigeminal Structure of DNA

A novel electrochemiluminescence (ECL) biosensor for highly sensitive and selective detection of Ag+ is developed based on the sensitive “turn-on” structure-switching trigeminal structure of deoxyribonucleic acid (DNA-TS). DNA-TS consists of three oligonucleotides hybridized to form three double-stranded DNA like Y-shaped DNA structure. The formation of DNA-TS makes the ECL sign Ru(bpy)2(mcbpy-O-Su-ester)(PF6)2 of reporter probe approach to the electrode surface and thus increase the ECL signal intensity. The “signal-on” ECL biosensor could detect Ag+ concentration in the range from 1.0 × 10-11 to 3.2 × 10-9 mol L-1, and the limit of detection is 3.0 × 10-12 mol L-1. The strategy is sensitive and rapid. This approach could be extended to the design of sensors for other desired heavy metal ions as well. Such ECL sensors are promising for sensitive detection of other heavy metal ions.本研究开发了一种基于脱氧核糖核酸（deoxyribonucleic acid, DNA）敏感“开启型”结构切换三叉结构（DNA-TS）的新型电化学发光（electrochemiluminescence, ECL）生物传感器，可实现银离子（Ag+）的高灵敏度、高选择性检测。DNA-TS由三条寡核苷酸杂交形成类Y形DNA结构的三条双链DNA所构成。DNA-TS的形成可使报告探针携带的ECL信号物质Ru(bpy)2(mcbpy-O-Su-ester)(PF6)2趋近电极表面，从而提升ECL信号强度。该信号开启型ECL生物传感器对Ag+的检测浓度区间为1.0×10^-11 至 3.2×10^-9 mol·L^-1，检出限为3.0×10^-12 mol·L^-1。该检测策略灵敏度高、响应快速，且可推广应用于其他目标重金属离子传感器的设计。此类ECL生物传感器在其他重金属离子的高灵敏检测领域具备良好应用前景。