Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070, PR China.
Key Laboratory of Bioelectrochemistry & Environmental Analysis of Gansu Province, College of Chemistry & Chemical Engineering, Northwest Normal University, Lanzhou 730070, PR China; Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, PR China.
Biosens Bioelectron. 2018 May 30;106:64-70. doi: 10.1016/j.bios.2018.01.052. Epub 2018 Jan 31.
An ultrasensitive and stable "dual-potential" ratiometric electrochemiluminescence (ECL) sensor is reported for specific DNA, the femtomolar detection limit (0.12 fM, S/N = 3) and high selectivity insure its potential applications in cancer biomarkers searching or monitoring. The excellent performance of the sensor comes from simultaneously fabricated layer by layer structure "target DNA + Hemin / Au-Luminol NPs / DNA* / sl DNA / TGA / QDs / MWNTs / GCE" mode which was based on the enhancing effect of luminol by G-quadruplex / hemin and Au nanoparticles and the quenching effect of CdSe/ZnS by G-quadruplex / hemin. (i) DNA-SH could combine with Au-Luminol NPs via S-Au bond to solve the problem of poor solubility and weak ECL intensity of luminol in neutral medium. (ii) Target DNA and Hemin formed the G-quadruplex / hemin peroxidase mimicking DNAzyme could enhance the ECL of luminol and quench the ECL of CdSe/ZnS simultaneously. (iii) DNA* was employed to increase a certain distance between CdSe/ZnS and Au-Luminol for enhancing the CdSe/ZnS QDs initial ECL intensity. The dual-potential ratiometric mode lower the influence of background and side reaction of the ECL sensor which were the most important factors in trace sensing.
一种超灵敏和稳定的“双电位”比率型电化学发光（ECL）传感器被报道用于特定的 DNA，其检测限低至飞摩尔（0.12 fM，S/N = 3），高选择性确保了其在癌症生物标志物检测或监测方面的潜在应用。该传感器的优异性能来自于同时构建的层层结构“目标 DNA + 血红素/ Au-发光氮纳米颗粒/ DNA* / sl DNA / TGA / QDs / MWNTs / GCE”模式，该模式基于 G-四链体/血红素和 Au 纳米颗粒对发光氮的增强效应，以及 G-四链体/血红素对 CdSe/ZnS 的猝灭效应。（i）DNA-SH 可以通过 S-Au 键与 Au-发光氮纳米颗粒结合，解决发光氮在中性介质中溶解度差和 ECL 强度弱的问题。（ii）目标 DNA 和血红素形成 G-四链体/血红素过氧化物酶模拟 DNA 酶，可增强发光氮的 ECL，并同时猝灭 CdSe/ZnS 的 ECL。（iii）DNA* 被用来增加 CdSe/ZnS 和 Au-发光氮之间的一定距离，以增强 CdSe/ZnS QDs 的初始 ECL 强度。双电位比率型模式降低了 ECL 传感器背景和副反应的影响，这是痕量检测中最重要的因素。
