中文摘要：

该研究首次将DNA分子机器—DNA纳米镊子引入到ECL传感体系中,并设计构建了新型的DNA酶诱导的目标物循环放大的电致化学发光生物传感器,用于超灵敏检测癌症细胞中的microRNA。首先,目标物microRNA-21依次打开两个发夹型探针,形成“Y”型DNA结构。通过DNA酶（Pb~（2＋））的剪切实现了目标物的循环放大,并得到了大量的DNA引发链。该引发链可“关闭”DNA纳米镊子,随着镊子两端的发光物质靠近而发生能量转移,钌将能量转移给量子点,因而量子点电致化学发光信号得到显著增强。在优化的实验条件下,线性范围为10 nmol/L~0.1 pmol/L,检测限为0.03 pmol/L（S/N=3）。该研究通过引入新型的DNA分子机器,拓展了DNA纳米技术在生物传感及临床诊断方面的应用,对于疾病诊断及预防具有重要的理论意义及实用价值。

英文摘要：

A novel electrochemiluminescence （ECL） biosensor was constructed for the highly-sensitive detection of microRNA-21 coupling with the target recycling amplification and the DNA nanomachine. First, the primer probe with assistant probe and miRNA formed Y junction which was cleaved with the addition of Pb2＋ to release microRNA. Subsequently, the released microRNA could initiate the next recycling process, leading to the generation of numerous DNA reporters. In the presence of the DNA reporters, the tweezer transformed to ＂closed＂ state through the hybridization of reporter DNA and generate ERET of Ru（bpy）3^2＋ and QDs, increasing the ECL intensity of QDs remarkably. The proposed biosensor realized high sensitive detection of the microRNA in cancer cell. The linearity range was 10 nmol/L-0.1 pmol/L with a detection limit down to 0.03 pmol/L（S/N = 3）. This work offers a new modular platform for the construction of DNA nanomachines which could serve as an effective signal amplification strategy for the real application in biosensing and clinical diagnosis.