Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, School of Chemistry and Chemical Engineering , Southwest University , Chongqing 400715 , PR China.
Anal Chem. 2019 Jun 18;91(12):7782-7789. doi: 10.1021/acs.analchem.9b01266. Epub 2019 Jun 7.
A programmed dual-functional DNA tweezer (DFDT) as a signaling molecule is reported for the simultaneous and recognizable fluorescence detection of microRNA 21 (miRNA 21) and mucin 1 (MUC1). This unique DFDT is assembled from two Au-NP-attached central strands (C1 and C2) and an arm strand (A) dually ended by fluorophores Cy3 and Cy5, which are spatially separated from Au NP in the originally opened state. Through the competitive affinity interaction between targets and their complementary and aptamer sequences tethered in two recognition strands (R1 and R2), miRNA 21 and MUC1 are respectively converted into two dependently displaced fuel strands (F1 and F2). The next hybridization with two pairs of unpaired segments overhung in open DFDT leads to its conformational closure, resulting in the approach of Cy3 and Cy5 to Au NP. On the basis of the nanometal surface energy transfer scheme, the fluorescence emission of Cy3 or Cy5 is cooperatively quenched by Au NPs attached in C1 and C2. The significant variation of fluorescence intensity enables one-step, cost-effective, and specific quantization of miRNA 21 and MUC1 with high sensitivity down to 32 fM and 2.6 fg·mL (8.5 pM), respectively. The novel DFDT-based assay route of multiplex analytes is promising and has the potential for rapid and reliable diagnosis and treatment of cancer-related diseases.
一种可编程双功能 DNA 镊子（DFDT）作为信号分子，用于同时且可识别地荧光检测 microRNA 21（miRNA 21）和粘蛋白 1（MUC1）。这种独特的 DFDT 由两个 Au-NP 附着的中心链（C1 和 C2）和一个臂链（A）组装而成，臂链的两端分别带有荧光团 Cy3 和 Cy5，在最初打开的状态下，Cy3 和 Cy5 与 Au NP 在空间上分开。通过目标物与两个识别链（R1 和 R2）中连接的互补和适体序列之间的竞争亲和力相互作用，miRNA 21 和 MUC1 分别转化为两个依赖位移的燃料链（F1 和 F2）。接下来，与开放 DFDT 中伸出的两对未配对片段进行杂交，导致其构象闭合，从而使 Cy3 和 Cy5 接近 Au NP。基于纳米金属表面能量转移方案，附着在 C1 和 C2 中的 Au NPs 协同猝灭 Cy3 或 Cy5 的荧光发射。荧光强度的显著变化使得一步、经济高效且特异性地量化 miRNA 21 和 MUC1 成为可能，其灵敏度分别低至 32 fM 和 2.6 fg·mL（8.5 pM）。基于新型 DFDT 的多重分析物分析方法具有广阔的前景，有望用于癌症相关疾病的快速可靠诊断和治疗。
