循环miRNA的发现为癌症的早期诊断和无创诊断提供了新的方向，但其序列短、含量低、相似度高等自身限制给检测方法提出了巨大挑战。本项目提出基于DNA纳米界面生物传感技术和数字PCR技术联合检测循环miRNA的方法，DNA纳米界面生物传感通过构建一种DNA纳米探针界面特异性识别目标miRNA，利用酶催化放大电化学信号实现高通量、高灵敏的电化学循环miRNA检测；同时数字PCR技术具有通量高、样品需要量少、绝对定量的优势，可以实现对循环miRNA的精确定量。本项目将DNA纳米界面生物传感和数字PCR两项关键技术结合，通过优势互补和联合验证，解决miRNA检测应用于癌症早期检测的灵敏度、准确性和检测通量等核心问题，并且通过开展病人血液实际样品的检测，为miRNA在癌症检测中的扩展应用提供数据支持。

The discovery of circulating miRNA provides a new direction for the early diagnosis and noninvasive diagnosis of cancer, but its detection methods largely remain a technical challenge due to the low abundance, short length and sequence similarity of miRNAs. In this project, we combined DNA nanostructure-based biosensor and digital PCR for circulating miRNA detection. In DNA nano-structured biosensor, we constructed DNA nano-structured probe for specific recognizing target miRNA and uesd enzyme to amplify the electrochemical siganl, which can realize high throughput, high sensitive electrochemical cyclic miRNA detection; meanwhile, the digital PCR with high throughput, less sample, absolute quantitative advantages was employed to achieve precise quantification of circulating miRNA.This project will combine two key technologies of DNA nano-structured biosensor and digital PCR, to not only possess their own advantages but also confirm theirselves with each other. In order to improve the sensitivity, accuracy, detection throughput and other problems in miRNA detection, systematic research will be performed in our project. Further more, the practical application of our developed methods will be challenged by analyzing patient blood samples. Our results will provide strong support for the extended application of miRNA in cancer detection.