Yao Tong, Chen Jie, Kong Lingqi, Liu Ying, Yuan Ruo, Chai Yaqin
Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, P. R. China.
Department of Endocrinology, 9th People's Hospital of Chongqing, Chongqing 400700, P. R. China.
Anal Chem. 2023 Sep 5;95(35):13211-13219. doi: 10.1021/acs.analchem.3c02212. Epub 2023 Aug 22.
Herein, a giant-sized DNA nanoarray was subtly assembled by two kinds of independent tetrahedral DNA structures as the DNA track for a multi-armed three-dimensional (3D) DNA nanomachine to perform signal transduction and amplification efficiently, which was developed as an electrochemical biosensor for the rapid and ultrasensitive detection of matrix metalloproteinase 2 (MMP-2). Impressively, in contrast to conventional DNA walkers with inefficiency, which walked on random DNA tracks composed of a two-dimensional (2D) probe or a one-dimensional (1D) single-stranded (ss)DNA probe, the multi-armed 3D DNA nanomachine from exonuclease III (Exo III) enzyme-assisted target recycling amplification would be endowed with faster reaction speed and better walking efficiency because of the excellent rigidity and orderliness of the tetrahedral DNA nanoarray structure. Once the hairpin H-label with the signal substance ferrocene (Fc) was added to the modified electrode surface, the multi-armed 3D DNA nanomachine would be driven to move along the well-designed nanoarray tracks by toehold-mediated DNA strand displacement, resulting in most of the ferrocene (Fc) binding to the electrode surface and a remarkable increase in electrochemical signals within 60 min. As a proof of concept, the prepared biosensor attained a low detection limit of 11.4 fg/mL for the sensitive detection of the target MMP-2 and was applied in Hela and MCF-7 cancer cell lysates. As a result, this strategy provided a high-performance sensing platform for protein detection in tumor diagnosis.
在此，通过两种独立的四面体DNA结构巧妙地组装了一种巨型DNA纳米阵列，作为多臂三维（3D）DNA纳米机器的DNA轨道，以高效地进行信号转导和放大，该纳米阵列被开发为一种用于快速超灵敏检测基质金属蛋白酶2（MMP - 2）的电化学生物传感器。令人印象深刻的是，与在由二维（2D）探针或一维（1D）单链（ss）DNA探针组成的随机DNA轨道上行走的低效传统DNA步行器相比，来自核酸外切酶III（Exo III）酶辅助靶标循环扩增的多臂3D DNA纳米机器由于四面体DNA纳米阵列结构具有出色的刚性和有序性，将具有更快的反应速度和更好的行走效率。一旦将带有信号物质二茂铁（Fc）的发夹H标记物添加到修饰电极表面，多臂3D DNA纳米机器将通过链置换介导的DNA链置换沿着精心设计的纳米阵列轨道移动，导致大部分二茂铁（Fc）与电极表面结合，并在60分钟内使电化学信号显著增加。作为概念验证，制备的生物传感器对目标MMP - 2的灵敏检测达到了11.4 fg/mL的低检测限，并应用于Hela和MCF - 7癌细胞裂解物中。因此，该策略为肿瘤诊断中的蛋白质检测提供了一个高性能的传感平台。
