可以稳定地存在于外周血的循环miRNA（cmiRNA）与肿瘤、代谢和心血管等重要疾病发生、发展进程有关，是理想的非侵袭性早期疾病诊断分子标志物。本项目针对肝癌特异性cmiRNAs的分离富集、高灵敏检测问题开展研究，评估相关cmiRNA在外周血不同组分不同亚群中的表达差异、定量分布特点及临床诊断意义；建立cmiRNA不同组分（如囊泡包裹形式、蛋白复合体形式等）提取纯化新技术，采用微流控体积排阻色谱及免疫磁珠技术设计多通道微流控芯片，实现cmiRNA不同组分的高通量、自动化、高效分离富集；建立多种基于酶催化靶标循环及纳米强化信号放大的cmiRNA高灵敏检测新方法，设计构筑外周血样本处理、cmiRNA组分纯化及分类检测的一体化微流控芯片。本项目研究为肿瘤早期诊断、分型、预后、疗效预测及疾病复发预测等提供一种简单有效的基于新型肿瘤标志物cmiRNAs的非损伤性检测手段。

MicroRNAs are small (typically ≈22 nt in size) regulatory RNA molecules that play important roles in a wide range of physiologic and pathologic processes. Circulating MicroRNAs (cmiRNAs), first discovered in human blood in 2008, are found to be significantly correlated with the occurance and development of cancer, metabolic disorder, and cardiovascular disease, and can serve as a novel class of blood-based disease biomarkers. This project focuses on the separation and detection of hepatocellular carcinoma-related cmiRNAs. We will define distribution of these cmiRNAs in clinical samples of plasma and serum in different stable forms, including encapsulation in membrane-bound vesicles and miRNA-protein complexes, and develop the novel methods based on micro-size-exclusion chromatography and magnetic bead immunoaffinity for efficiently purifying various populations of cmiRNAs (cmiRNAs associated with exosomes, microvesicles, and apoptotic bodies; miRNA- Ago2; miRNA-NPM1; miRNA-HDL) in peripheral blood. The separation and identification of distinct cmiRNA populations, originating from different cell types and reflecting cell type-specific miRNA expression and/or release mechanisms, may increase biomarker sensitivity and provide more precise information for clinical diagnosis or prognosis. We will also establish the ultrasensitive detection methods of cmiRNAs based on target assisted enzyme-catalyzed signal amplification and nanoparticle-enhancement, and construct integrated high-throughput microfluidic chip for sample processing, purification and quantitative determination of distinct cmiRNA populations in human blood. Our researches lay the foundation for the development of circulating miRNAs as a novel class of blood-based disease biomarkers.