基于量子点-DNA纳米结构电化学体系的肿瘤标志物单细胞水平检测方法研究

Tumor markers (such as telomerase, thymine DNA glycosylase and circulating tumor miRNA) have been considered to be an important quota for early cancer diagnostic. Highly sensitive and selective detection of tumor marker is crucial for cancer diagnosis, monitoring and targeted drug screening. In this project, we will develop several highly sensitive, selective and stable biosensors using quantum dots-DNA nanostructures as bio-nanoprobe. Taking advantages of the electrochemical method and cell imaging techniques, the obtained biosensor will be employed to determine the tumor marker at the single-cell level, intracellular in situ and real sample analysis. Firstly, various kinds of quantum dots such as CdTe, silver nanoclusters, copper nanoclusters will be synthesized via sonochemistry, microwave-assisted, and hydrothermal method by the aid of the biomolecule template. Then, various 3D DNA nanostructures with different configurations will be obtained with the technology of rolling circle amplification and hybridization chain reaction. These DNA nanostructures will be further conjugated with quantum dots, and assembled into bio-nanoprobes with unique optical and electrochemical properties, and the capability of specific recognition for tumor marker. We will also investigate the mechanism of the fabrication for DNA nanostructure and biosensor, discuss the effect of the DNA configuration on the performance of the biosensor, and finally improve the sensitivity, selectivity and stability of biosensor significantly.

肿瘤标志物（如端粒酶、胸腺嘧啶DNA糖基化酶和肿瘤循环miRNA）是癌症早期诊断的重要检测指标，针对它们的高灵敏、高特异性检测对癌症的早期诊断、监测和药物筛选有重大意义。本项目拟将量子点-DNA纳米结构生物纳米探针应用于灵敏度高、特异性好和性能稳定的生物传感器的构建，通过电化学方法和细胞成像技术实现标志物的单细胞水平检测、原位成像和实样分析。首先采用超声化学、微波辅助和水热等方法以生物小分子为模板合成多种量子点如碲化镉、银纳米簇和铜纳米簇；通过滚环扩增和碱基杂交链反应等DNA技术构筑具有不同构型的三维DNA纳米结构；以此为载体与量子点结合组装多功能生物纳米探针，赋予探针优良的光电性能和高效识别标志物的能力；探讨量子点和DNA纳米结构的形成及传感分析的机理，讨论DNA结构对传感器性能的影响，以期在传感器的灵敏度、特异性和稳定性等方面有明显改善。

癌症标志物的检测是癌症早期诊断的重要依据。MicroRNA、DNA糖基化酶是某些癌症的新型标志物，与癌症的形成过程密切相关。本项目以量子点为基础制备量子点-DNA纳米结构的生物纳米探针，构建功能化的传感界面，研究癌症标志物的检测新方法，并探究其潜在的应用价值。主要研究工作包括：(1)采用微波、水热、等离子溅射等方法合成了荧光碳点、CdTe量子点、CuInS2量子点、ZnO纳米棒–Ag纳米粒子复合物、ZnO纳米棒–Au纳米粒子复合物、碳纤维/ZnO核壳杂化物、Au@CuOS蛋壳结构、中空NiS、FeMoO4等纳米材料；(2)基于以上纳米材料良好的电化学和类酶催化特性构建功能化的光电传感界面，如；基于Au@CuOS蛋壳结构、CuInS2量子点、中空NiS等纳米材料的类酶性质构建了比色传感界面，基于含铜碳点、ZnO纳米棒–Ag纳米粒子复合物等纳米材料构建电化学传感界面，实现对多个癌症标志物的感知；(3)发展一系列基于量子点-DNA纳米结构多功能纳米探针肿瘤标志物的检测新方法，如基于DNA-QDs树形超级纳米结构构建DNA糖基化酶检测传感器、基于目标物引发杂交链反应放大策略的无酶microRNA电化学传感器，为癌症的早期诊断提供一些有效的手段，对于新药开发具有重要意义。.本项目发表了论文12篇，主要发表在ACS Applied Materials & Interfaces, Biosensors and Bioelectronics, Sensors and Actuators B等杂志上，申报专利1 项，参加国内会议6次，培养2名硕士研究生，13名本科生，目前在培研究生8人。完成了任务书中制定的任务。

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