基于聚乙烯亚胺还原的金纳米颗粒为基底构建的“signal on”型高灵敏ECL传感器铅离子检测

A sensitive “signal-on” electrochemiluminescence sensor for Pb^(2+) based on polyethyleneimine reduced gold nanoparticles as matrix

该实验结合目标物循环与杂交链式反应(HCR)信号放大策略,构建了用于检测Pb^(2+)的"signal on"型ECL生物传感器。该传感器可以通过Pb^(2+)和脱氧核酶的特异识别作用,循环剪切固载在电极表面的发卡型底物链H0,在实现目标物循环的同时使得电极表面越多的H0被剪切为DNA残链,获得的DNA残链继而作为引物打开发夹探针H1和H2引发HCR反应,形成由H1和H2交替杂交形成的长双链聚合物。这些双链聚合物可以通过静电吸附作用固载大量的邻菲罗啉钌配合物(Ru(phen)3^(2+))。利用固载在电极基底的PEIAu复合纳米材料对发光试剂的共反应作用显著放大检测信号,构建了对Pb^(2+)的"signal on"模式ECL检测新方法。实验结果表明,在Pb^(2+)浓度范围为1×10-12mol/L^1×10-8mol/L之间,表现出良好的线性关系,其检出限为3.33×10-13mol/L。

In this work,combining the target cycle with the hybridization chain reaction（HCR） signal amplification,the ＂signal-on＂ electrochemiluminescence（ECL） biosensor was successfully prepared for Pb^2＋detection.In the presence of Pb^2＋,the hairpin substrate chain H0 immoblized on the electrode,which was cleaved at the RNA site owing to the the oxidative cleavage to release a DNA fragments as the primer for repetitive cycling.The DNA fragments could open hairpin structure H1,and exposes a new terminus of H1 to further react with H2 to form a long ds DNA polymer.This long ds DNA polymer can immobilize a large amount of phenanthroline ruthenium complexes（Ru（phen）_3^2＋） via electrostatic adsorption interaction.Thus,a new ＂signal on＂ ECL test method for Pb^2＋was developed by using PEI-Au composite nanomaterial as a new co-reactant reagent for ECL intensity enhancement.The results showed that the prepared ECL biosensor was successfully applied for the determination of Pb^2＋with a linear detection range of 1×10^-12mol/L to 1×10^-8mol/L,the detection limit was 3.33× 10^-13mol/L.