College of Chemistry and §Analytical & Testing Center, Sichuan University , Chengdu, Sichuan 610064, China.
ACS Appl Mater Interfaces. 2015 Jan 14;7(1):696-703. doi: 10.1021/am506980d. Epub 2014 Dec 16.
A dual signal amplification strategy for electrochemiluminescence (ECL) aptasensor was designed based on biobar-coded gold nanoparticles (Au NPs) and DNAzyme. CdSeTe@ZnS quantum dots (QDs) were chosen as the ECL signal probes. To verify the proposed ultrasensitive ECL aptasensor for biomolecules, we detected thrombin (Tb) as a proof-of-principle analyte. The hairpin DNA designed for the recognition of protein consists of two parts: the sequences of catalytical 8-17 DNAzyme and thrombin aptamer. Only in the presence of thrombin could the hairpin DNA be opened, followed by a recycling cleavage of excess substrates by catalytic core of the DNAzyme to induce the first-step amplification. One part of the fragments was captured to open the capture DNA modified on the Au electrode, which further connected with the prepared biobar-coded Au NPs-CdSeTe@ZnS QDs to get the final dual-amplified ECL signal. The limit of detection for Tb was 0.28 fM with excellent selectivity, and this proposed method possessed good performance in real sample analysis. This design introduces the new concept of dual-signal amplification by a biobar-coded system and DNAzyme recycling into ECL determination, and it is promising to be extended to provide a highly sensitive platform for various target biomolecules.
一种基于双信号放大策略的电化学发光（ECL）适体传感器，是基于生物条形码编码的金纳米粒子（Au NPs）和 DNA 酶设计的。选择 CdSeTe@ZnS 量子点（QDs）作为 ECL 信号探针。为了验证所提出的用于生物分子的超灵敏 ECL 适体传感器，我们以凝血酶（Tb）作为原理验证分析物进行了检测。用于识别蛋白质的发夹 DNA 由两部分组成：催化 8-17 DNA 酶和凝血酶适体的序列。只有在存在凝血酶的情况下，发夹 DNA 才能被打开，随后通过 DNA 酶的催化核心对过量底物进行循环切割，以引发第一步放大。片段的一部分被捕获以打开修饰在 Au 电极上的捕获 DNA，这进一步与制备的生物条形码编码的 Au NPs-CdSeTe@ZnS QDs 连接，以获得最终的双重放大 ECL 信号。对于 Tb 的检测限为 0.28 fM，具有优异的选择性，并且该方法在实际样品分析中表现出良好的性能。该设计通过生物条形码系统和 DNA 酶循环将双信号放大的新概念引入 ECL 测定中，有望扩展为各种靶标生物分子提供高灵敏度的平台。
