An electrochemiluminescence (ECL) three-dimensional (3D) DNA nanomachine is developed for microRNA-141 (miRNA-141) detection by coupling Pb²⁺ dependent DNAzyme assisted target recycling amplification technology with multiple ECL resonance energy transfer (ECL-RET) system. Firstly, Pb²⁺ dependent DNAzyme is formed by three single strand DNA (ssDNA): A1, A2 and the target miRNA-141. In the presence of Pb²⁺, the specific recognition site of the DNAzyme is cleaved and a large number of secondary targets (A3) are released. Secondly, the 3D DNA nanomachine consists of four ssDNA: H1, H2, H3 and the probe (two ends are labeled with alexa fluor (AF) and a nanocomposite (PtNCs@Ru(dcbpy)₃²⁺) which is prepared by polyethyleneimine platinum nanoclusters and tris(4,4′-dicarboxylicacid-2,2′-bipyridyl) ruthenium(II) dichloride). Then, the 3D DNA nanomachine is assembled on the gold nanoparticles modified glassy carbon electrode. Afterwards, A3 is employed to hybridize with the probe, triggering the movement of the nanomachine and forming the multiple ECL-RET system. In this system, AF, serves as an effective energy transfer donor, which can transfer energy to PtNCs and Ru(dcbpy)₃²⁺directly. Meanwhile, PtNCs, both as the acceptor and donor, can accept energy from AF and transfer it to Ru(dcbpy)₃²⁺. As a result, The biosensor achieves enhanced ECL efficiency, which is 1.78 times that of the classic tris(2,2′-bipyridyl)ruthenium(II) dichloride (Ru(bpy)₃²⁺) and exhibits good responses to miRNA-141 in the linear range from 10 aM to 100 nM with a detection limit of 3.3 aM. Also, the obtained biosensor can be employed to detect miRNA-141 in human serum samples, which will be of great significance in bioanalysis.

电化学发光（ECL）三维（3D）DNA纳米机器被开发用于通过结合Pb ²⁺依赖的DNAzyme辅助靶循环扩增技术与多重ECL共振能量转移（ECL-RET）系统来检测microRNA-141（miRNA-141）。首先，Pb ²⁺依赖的DNAzyme由三个单链DNA（ssDNA）形成：A1，A2和靶标miRNA-141。在Pb ²⁺的存在下，^DNAzyme的特异性识别位点被切割，并释放出大量的次要靶标（A3）。其次，3D DNA纳米机器由四个ssDNA组成：H1，H2，H3和探针（两端用alexa fluor（AF）和纳米复合物（PtNCs @ Ru（dcbpy）₃ ²⁺标记））是由聚乙烯亚胺铂纳米簇和三（4,4'-二羧酸-2,2'-联吡啶基）二氯化钌（II）制备的。然后，将3D DNA纳米机器组装在金纳米粒子修饰的玻碳电极上。之后，使用A3与探针杂交，触发纳米机械的运动并形成多重ECL-RET系统。在该系统中，AF是有效的能量传递供体，可以将能量直接传递给PtNC和Ru（dcbpy）₃ ²⁺。同时，PtNCs既可以作为受体也可以作为供体，可以从AF接收能量并将其转移到Ru（dcbpy）₃ ²⁺。结果，该生物传感器实现了增强的ECL效率，这是经典的三氯化三（2,2'-联吡啶基）钌（II）（Ru（bpy））的1.78倍₃ ²⁺）并在从10 aM到100 nM的线性范围内表现出对miRNA-141的良好响应，检测限为3.3 aM。而且，所获得的生物传感器可用于检测人血清样品中的miRNA-141，这在生物分析中将具有重要意义。