Department of Pharmaceutical Engineering, School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China.
Anal Methods. 2021 Jul 7;13(25):2823-2829. doi: 10.1039/d1ay00390a. Epub 2021 Jun 1.
Specific and sensitive biomarker detection is significant for the early diagnosis of cancers. Herein, a highly sensitive electrochemical biosensor employing a tetrahedral DNA nanostructure (TDN) probe and multiple signal amplification strategies has been constructed, and successfully applied to microRNA-122 (miR-122) detection. The platform consisted of a TDN probe anchoring on a gold nanoparticle-coated gold electrode and multiple signal amplification procedures combining the electrodeposition of gold nanoparticles, hybridization chain reaction (HCR), and horseradish peroxidase enzymatic catalysis (HPEC). In the presence of the target, the hairpin structure of the helper probe could be opened and trigger the HCR through the hybridization of H1 and H2 probes, and then avidin-HRP was attached on the surface of the gold electrode that can produce an electro-catalytic signal. We used TDN probe as the scaffold to increase the reactivity and multiple signal amplification greatly improve the sensitivity of this biosensor. This biosensor offers an excellent sensitivity (a limit of detection of 0.74 aM) and differentiation ability for single and multiple mismatches. This multiplexing biosensor for trace microRNA detection shows promising applications in the early diagnosis of cancer.
特异性和灵敏的生物标志物检测对于癌症的早期诊断具有重要意义。在此，构建了一种基于四面体 DNA 纳米结构（TDN）探针和多种信号放大策略的高灵敏度电化学生物传感器，并成功应用于 microRNA-122（miR-122）检测。该平台由一个锚定在金纳米粒子修饰的金电极上的 TDN 探针和多个信号放大程序组成，该程序结合了金纳米粒子的电沉积、杂交链式反应（HCR）和辣根过氧化物酶酶催化（HPEC）。在存在靶标的情况下，辅助探针的发夹结构可以打开，并通过 H1 和 H2 探针的杂交触发 HCR，然后亲和素-HRP 可以附着在金电极表面上，从而产生电催化信号。我们使用 TDN 探针作为支架，大大提高了反应性和多重信号放大，从而提高了该生物传感器的灵敏度。该生物传感器对单碱基和多位点错配具有优异的灵敏度（检测限为 0.74 aM）和区分能力。这种用于痕量 microRNA 检测的多重生物传感器在癌症的早期诊断中具有广阔的应用前景。
