Nowadays, novel and efficient signal amplification strategy in electrochemiluminescence (ECL) platform is urgently needed to enhance the sensitivity of biosensor. In this work, the dual ECL signal enhancement strategy was constructed by the interactions of Pd nanoparticles attached covalent organic frameworks (Pd NPs@COFs) with tris (bipyridine) ruthenium (RuP) and Exonuclease III (Exo.III) cycle reaction. Within this strategy, the COFs composite was generated from the covalent reaction between 2-nitro-1,4-phenylenediamine (NPD) and trialdehyde phloroglucinol (Tp), and then animated by glutamate (Glu) to attach the Pd NPs. Next, the “signal on” ECL biosensor was constructed by the coordination assembly of thiolation capture DNA (cDNA) onto the Pd NPs@COFs modified electrode. After the aptamer recognition of progesterone (P4) with hairpin DNA 1 (HP1), the Exo. III cycle reaction was initiated with HP2 to generate free DNA, which hybridized with cDNA to form double-stranded DNA (dsDNA). For that, the RuP was embedded into the groove of dsDNA and achieved the ultrasensitive detection of P4 with a lower limit of detection (LOD) down to 0.45 pM, as well as the excellent selectivity and stability. This work expands the COFs-based materials application in ECL signal amplification and valuable DNA cyclic reaction in biochemical testing field.

中文翻译：

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Pd纳米颗粒附着共价有机框架和核酸外切酶循环反应的双重ECL信号增强策略用于超灵敏检测孕酮

如今，迫切需要电化学发光（ECL）平台中新颖有效的信号放大策略来提高生物传感器的灵敏度。在这项工作中，通过附着共价有机框架的钯纳米颗粒（Pd NPs@COFs）与三（联吡啶）钌（RuP）和核酸外切酶III（Exo.III）循环反应的相互作用构建了双重ECL信号增强策略。在该策略中，COF 复合材料是通过 2-硝基-1,4-苯二胺 (NPD) 和三醛间苯三酚 (Tp) 之间的共价反应生成的，然后通过谷氨酸 (Glu) 活化以附着 Pd NP。接下来，通过将硫醇捕获 DNA (cDNA) 配位组装到 Pd NPs@COFs 修饰电极上，构建了“信号打开”ECL 生物传感器。适配体与发夹 DNA 1 (HP1) 识别黄体酮 (P4) 后，Exo.用HP2启动III循环反应产生游离DNA，其与cDNA杂交形成双链DNA(dsDNA)。为此，将RuP嵌入双链DNA的凹槽中，实现了P4的超灵敏检测，检测下限（LOD）低至0.45 pM，并且具有优异的选择性和稳定性。这项工作拓展了COFs基材料在ECL信号放大和生化检测领域有价值的DNA循环反应中的应用。