Key Laboratory of Luminescence Analysis and Molecular Sensing, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Anal Chem. 2022 Jan 18;94(2):1264-1270. doi: 10.1021/acs.analchem.1c04489. Epub 2021 Dec 28.
Herein, a novel two-dimensional ladder-like DNA nanostructure (LDN)-mediated cascade catalytic nanomachine (LDN-CCN) with a higher catalytic efficiency beyond those of a conventional one-dimensional hybrid chain reaction (HCR) nanostructure-mediated CCN was constructed and applied to design an electrochemical biosensing platform with first-rank performance for ultrasensitive detection of target miRNA-21. First, output DNA S1' and S2' were produced through the DNAzyme recycle amplification when the target miRNA-21 existed. Then, the controllable LDN-CCN was constructed on S1-S2 modified electrodes by the subsequent reaction triggered by S1' and S2' with H1-AuNPs, H2, H3-AuNPs, and H4 with the assistance of K and hemin, in which the hemin/G-quadruplexes could produce a prominent electrochemical signal response to the substrate glucose. The best performance of cascade catalysis was acquired when the distance of Au nanoparticles (glucose oxidase-like activity) modified on H1 and H3 and hemin/G-quadruplexes (peroxidase-like activity) formed by the sticky ends of H2 and H4 was roughly 9 nm (27 bp) in LDN-CCN. The constructed electrochemical platform realized the sensitive detection of target miRNA-21 with the linear range from 100 aM to 10 nM and with a detection limit as low as 48.5 aM, which provided novel insights to explore the new functional DNA nanostructure and well-performing mimic enzyme cascade catalytic platforms for applications in biological fields and early diagnosis of diseases.
本文构建了一种新型二维梯型 DNA 纳米结构（LDN）介导的级联催化纳米机（LDN-CCN），其催化效率高于传统的杂交链式反应（HCR）纳米结构介导的 CCN，用于设计电化学生物传感平台，用于超灵敏检测靶 miRNA-21。首先，当存在靶 miRNA-21 时，通过 DNA 酶循环扩增产生输出 DNA S1'和 S2'。然后，通过 S1'和 S2'与 H1-AuNPs、H2、H3-AuNPs 和 H4 的后续反应，在 S1-S2 修饰电极上构建可控的 LDN-CCN，在 K 和血红素的辅助下，其中血红素/G-四链体可以产生显著的电化学信号响应底物葡萄糖。当 LDN-CCN 中修饰的 Au 纳米粒子（葡萄糖氧化酶样活性）与 H2 和 H4 的粘性末端形成的血红素/G-四链体（过氧化物酶样活性）之间的 Au 纳米粒子（葡萄糖氧化酶样活性）之间的距离大致为 9nm（27bp）时，级联催化获得最佳性能。构建的电化学平台实现了对靶 miRNA-21 的灵敏检测，线性范围从 100aM 到 10nM，检测限低至 48.5aM，为探索新型功能 DNA 纳米结构和高性能模拟酶级联催化平台在生物领域和疾病早期诊断中的应用提供了新的思路。
