基于荧光DNA银纳米簇水凝胶构建荧光分析系统用于肿瘤标志物microRNA检测

DNA templated Ag nanoclusters have attracted special research interests in the fields of DNA nanotechnology and fluorescent materials in the past decade. These novel fluorophores exhibit bright fluorescence emission with high photostability, and their fluorescent emission is highly dependent on the sequences of the DNA templates. The emission spectra can be tuned in the range from visible to near-infrared just by varying the DNA template sequences. Therefore, they are powerful fluorescence probes in analytical chemistry fields. Here, we proposed a multifunctional fluorescence analysis system based on DNA hydrogels composed of fluorescent DNA-Ag nanoclusters for the detection of microRNA as the tumor marker. The hydrogel systems were designed to response to specific microRNA targets and release fluorescent DNA Ag nanoclusters to generate fluorescence signals. Benefit from the multi-color fluorescence emissions of different DNA templated Ag nanoclusters and the programmed specific DNA responses to different microRNA targets, a fluorescence analysis system which can smartly response to different microRNA targets can be developed. The proposed analysis system has the advantages of low detection background, environmentally friendly, low-cost, easy to operate, and so on. Furthermore, the analysis system can be easily expanded to the detection of other biochemical targets. The system will have great potential in the future analytical applications, especially in the fields of cancer early diagnosis, biochemical analysis and disease diagnosis.

DNA荧光银纳米簇是过去十多年间在DNA纳米技术和荧光材料领域一个新兴的热点。这种荧光团有荧光发射强和光稳定性高等优点，特别是其荧光发射对DNA模板序列具有很强依赖性，可通过改变序列在可见到近红外谱带可调。DNA荧光银簇作为荧光探针在分析化学研究领域具有很大的应用价值。本项目提出构建一个以肿瘤标志物microRNA为检测目标，基于荧光DNA银纳米簇水凝胶体系的多功能荧光分析系统。利用DNA水凝胶中的编入的DNA识别结构对目标microRNA的响应来控制释放荧光银簇从而输出荧光信号。并且，利用可以通过调控DNA序列形成不同发射波长的荧光银簇这一特点，可进而设计出对不同microRNA目标响应、释放不同荧光银簇的智能多目标分析系统。这种分析系统具有低检测背景、环境友好、低成本、易于操作等优点，且可方便拓展到其它生化分析体系，在未来癌症早期诊断、生化分析、疾病检测等领域有着广泛应用潜力。

本项目力图通过结合智能响应性DNA水凝胶体系和荧光DNA银纳米簇等功能探针体系发展新型的智能DNA水凝胶传感体系，进而将其应用于microRNA等重要生化目标的分析检测。在项目执行期内，在项目预定的多个方面取得了一系列重要进展：为解决DNA水凝胶体系中功能小分子可控释放的问题，发展了脂质体作为水凝胶的多交联单元并可用于功能小分子可控释放的新型DNA智能水凝胶体系；通过利用聚阳离子保护荧光DNA银纳米簇，解决了DNA荧光银纳米簇在生理条件下不稳定和不易进入细胞等不利于生化传感应用的问题，成功实现了其在快速生物成像中的应用；发展了多功能、可循环的智能DNA微凝胶传感体系，有望大大降低DNA水凝胶传感的成本，发展了可对microRNA高灵敏检测的DNA水凝胶传感体系，并应用于实际样的分析检测等。这些新型DNA水凝胶功能传感体系有望在未来的癌症早期诊断、疾病检测等生化分析应用领域中发挥一定作用。