一种基于脱氧核酶的铅离子电致化学发光传感器

本文设计了一种基于脱氧核酶(DNAzyme)检测Pb2+的电致化学发光(Electrocheluminescent,ECL)传感器。将对Pb2+特异性识别的DNAzyme通过金-巯键固定于金电极表面,并与标记有二氧化硅包埋的钌联吡啶(Ru-SNPs)的底物DNA链发生杂交,形成双链DNA(ds-DNA)传感器。Pb2+不存在时,由于Ru-SNPs靠近电极表面,产生强的ECL信号。当Pb2+存在时,DNAzyme催化底物链断裂,Ru-SNPs远离电极表面,导致ECL信号下降。实验结果表明ECL强度与Pb2+浓度在0.2-1.0 nmol/L范围内呈良好的线性关系,检测限可达0.04 nmol/L,其他二价金属离子对其基本无干扰。

An electrochemiluminescent sensor for lead ion based on DNAzyme

Here we design an electrochemiluminescent （ECL） DNAzyme-based sensor for detection Pb2＋. In this sensor, DNAzyme is immobilized on the gold electrode via Au-thiol interaction, and then hybridizes with DNAzyme substrate labeled with tris （ 2,2＇ - bipyridyl） ruthenium （II） - doped silica nanoparticles （ Ru- SNPs）, forming double- stranded DN A （ds-DNA） sensor. In the absence of Pb2＋ Ru-SNPs approach the electrode, which can generate a strong ECL signal. While in the presence of Pb2＋ DNAzyme can catalyzes the hydrolytic cleavage of the ds-DNA, and then remove Ru-SNPs away from the electrode, resulting in the reduction of ECL intensity. The result shows that the ECL intensity decreases linearly with Pb2＋ concentration in the rang of 0.2-1.0 nmol/L and the detection limit for Pb2＋ is 0.04 nmol/L. In addition, the ECL response to other divalent metal ions is negligible.