Accurate quantitative detection of DNA is an advanced strategy in various fields (such as disease diagnosis and environmental monitoring), but the classical DNA detection method usually suffers from low sensitivity, expensive thermal cyclers, or strict annealing conditions. Herein, a MOF-ERA platform for ultrasensitive HBV-DNA detection is constructed by integrating metal–organic framework (MOF)-mediated double energy transfer nanoprobe with exonuclease III (Exo III)-assisted target recycling amplification. The proposed double energy transfer containing a donor and two receptors is simply composed of MOFs (UiO-66-NH₂, a well-studied MOF) modified with a signal probe formed by the hybridization of carboxyuorescein (FAM)-labeled DNA (FDNA) and black hole quencher (BHQ1)-terminated DNA (QDNA), resulting in low fluorescence signal. After the addition of HBV-DNA, Exo III degradation to FDNA is activated, leading to the liberation of the numerous FAM molecules, followed by the generation of a significant fluorescence signal owing to the negligible binding of MOFs with free FAM molecules. The results certify that the MOF-ERA platform can be successfully used to assay HBV-DNA in the range of 1.0–25.0 nM with a detection limit of 97.2 pM, which is lower than that without BHQ1 or Exo III. The proposed method with the superiorities of low background signal and high selectivity holds promise for early disease diagnosis and clinical biomedicine applications.

中文翻译：

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MOF 介导的双能量转移纳米探针与核酸外切酶 III 扩增策略相结合，用于高灵敏度 DNA 检测

DNA的精确定量检测是各个领域（例如疾病诊断和环境监测）的先进策略，但经典的DNA检测方法通常存在灵敏度低、热循环仪昂贵或退火条件严格的问题。在此，通过将金属有机框架（MOF）介导的双能量转移纳米探针与核酸外切酶III（Exo III）辅助的靶标回收放大相结合，构建了用于超灵敏HBV-DNA检测的MOF-ERA平台。所提出的包含一个供体和两个受体的双能量转移简单地由 MOF（UiO-66-NH ₂，一种经过充分研究的 MOF）组成，并用羧基荧光素（FAM）标记的 DNA（FDNA）杂交形成的信号探针进行修饰。和黑洞猝灭剂 (BHQ1) 终止的 DNA (QDNA)，导致低荧光信号。添加 HBV-DNA 后，Exo III 被激活降解为 FDNA，导致大量 FAM 分子的释放，随后由于 MOF 与游离 FAM 分子的结合可忽略不计，因此产生了显着的荧光信号。结果证明MOF-ERA平台可以成功地用于检测1.0-25.0 nM范围内的HBV-DNA，检测限为97.2 pM，低于没有BHQ1或Exo III的检测限。该方法具有低背景信号和高选择性的优点，有望用于早期疾病诊断和临床生物医学应用。