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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。
In this paper, an electrochemiluminescent (ECL) sensor based on DNAzyme for detecting Pb2 + was designed. The DNAzyme specifically recognizing Pb2 + is immobilized on the surface of the gold electrode by gold-mercapto bond and hybridized with the substrate DNA chain labeled with silica-embedded ruthenium bipyridine (Ru-SNPs) to form double-stranded DNA ds-DNA) sensor. In the absence of Pb2 +, a strong ECL signal results due to the proximity of Ru-SNPs to the electrode surface. When Pb2 + is present, DNAzyme catalyzes the breakdown of the substrate chain and Ru-SNPs away from the electrode surface, resulting in a decrease in ECL signal. The experimental results show that the ECL intensity has a good linear relationship with the concentration of Pb2 + in the range of 0.2-1.0 nmol / L with the detection limit of 0.04 nmol / L. Other divalent metal ions have no interference.