MicroRNAs are short noncoding regulatory RNAs that are increasingly used as disease biomarkers. Rapid, sensitive, and quantitative microRNAs detection methods with high specificity are imperative. Here, we for the first time developed a DNA-functionalized metal-organic framework (MOF)-based ratiometric fluorescent probe using the interaction between Thiazole Orange (TO) dye and Rhodamine B(RhB) dye molecules, and achieved sensitive detection and imaging of miRNA-21 in living cells. Among them, DNA was successfully conjugated with MOF through the Zr-O-P bond in a single step with high efficiency. Based on this ratiometric fluorescent probe, picomolar limit detection (57 pM) for miRNA-21 can be obtained without signal amplification. After penetration into the cell, intracellular miRNA-21 can also be imaged by strand-displacement reaction, even distinguishing cancer cells from normal cells was achieved. This work paves the way for the development of DNA-functionalized MOF for intracellular molecules analysis and is of great significance for the early disease diagnosis.

MicroRNA 是一种短的非编码调控 RNA，越来越多地用作疾病生物标志物。快速、灵敏、定量的高特异性 microRNA 检测方法势在必行。在这里，我们首次利用噻唑橙（TO）染料和罗丹明B（RhB）染料分子之间的相互作用，开发了一种基于DNA功能化金属有机框架（MOF）的比率荧光探针，并实现了对DNA功能化金属有机框架（MOF）的灵敏检测和成像。活细胞中的 miRNA-21。其中，DNA通过Zr-OP键一步成功地与MOF结合，效率高。基于这种比率荧光探针，无需信号放大即可获得 miRNA-21 的皮摩尔极限检测 (57 pM)。渗透入细胞后，细胞内的 miRNA-21 也可以通过链置换反应成像，甚至可以区分癌细胞和正常细胞。该工作为开发用于细胞内分子分析的DNA功能化MOF铺平了道路，对疾病的早期诊断具有重要意义。