Achieving specific and sensitive imaging of mRNA in living cells plays a key role in cancer diagnosis and treatment. Catalytic hairpin assembly (CHA) has been widely used for mRNA imaging. However, it has been significantly constrained by limited in-depth amplifications. Herein, a novel feedback catalytic hairpin assembly (FCHA) with exponential amplification efficiency was proposed for mRNA imaging in living cells. The FCHA system consisted of with two hairpin DNAs (H, H) and a double stranded DNA (HL). After the probes enter the cell by using β-FeOOH nanoparticles (NPs) as delivery vector, the intracellular target Tk1 mRNA acted as catalyst to trigger the FCHA between H, H and HL, which achieved the exponential growth of CHA product. This FCHA system has demonstrated improved reaction kinetics and sensitivity compared to traditional CHA, which was 106 times more sensitive than conventional CHA. This strategy can be used for real-time imaging and indication of changes in the mRNA expression. This strategy slao can distinguish the expression difference of mRNA in normal and tumor cells, and can evaluate the anti-tumor drug’s efficacy. Benefiting from these outstanding advantages, we believe that this FCHA will become a powerful tool for early cancer diagnosis.

中文翻译：

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一种用于活细胞中敏感 mRNA 成像的新型反馈催化发夹组装策略

实现活细胞中 mRNA 的特异性和灵敏成像在癌症诊断和治疗中发挥着关键作用。催化发夹组装（CHA）已广泛用于 mRNA 成像。然而，它受到深度放大有限的严重限制。在此，提出了一种具有指数放大效率的新型反馈催化发夹组装（FCHA），用于活细胞中的 mRNA 成像。FCHA系统由两个发夹DNA（H，H）和一个双链DNA（HL）组成。探针以β-FeOOH纳米粒子(NPs)为递送载体进入细胞后，细胞内靶Tk1 mRNA作为催化剂触发H、H和HL之间的FCHA，从而实现CHA产物的指数增长。与传统 CHA 相比，该 FCHA 系统显示出改进的反应动力学和灵敏度，其灵敏度是传统 CHA 的 106 倍。该策略可用于实时成像并指示 mRNA 表达的变化。该策略slao可以区分正常细胞和肿瘤细胞中mRNA的表达差异，并可以评估抗肿瘤药物的疗效。受益于这些突出的优势，我们相信FCHA将成为早期癌症诊断的有力工具。