线粒体靶向的荧光金纳米团簇设计及其在细胞成像和检测中的应用

Gold nanoclusters (AuNCs) have shown great promise in the field of biomedicine because of their unique features including small size, low toxicity, good compatibility, facile modification, excellent chemical stability, large Stokes shift, long fluorescence lifetime, tunable luminescence emission, and robust resistance to photobleaching. Although some progress has been made in the design and synthesis of AuNCs for mitochondrial imaging, there still exists many deficiencies, such as low photoluminescence quantum yield, short emission wavelength, difficult to monitor the mitochondrial microenvironment and its related biomolecules. In addition, the relationship between composition/structure and target efficiency is still lack of in-depth study. This project aims at systematically study on the relationship between the target efficiency of AuNCs and their particle size, chemical composition, charge property, etc. The revealing mechanism and influence factors on target efficiency are used to guide the fabrication of highly mitochondria-targeting AuNCs. The designed AuNCs are subsequently used as fluorescent nanoprobes for mitochondrial imaging. Furthermore, different response types of targetable fluorescent AuNCs are constructed according to the mitochondrial microenvironment and the distribution of biomolecules in mitochondria.

金纳米团簇用作荧光探针具有粒径小、毒性低、生物相容性好、易修饰、化学稳定性高、斯托克斯位移大、荧光寿命长、光谱可调谐和抗光漂白能力强等突出优点，因此在生物医学领域中显示出巨大的应用前景。虽然当前对金纳米团簇在线粒体靶向成像方面的应用已经取得了一些进展，但是仍然存在许多不足之处，如荧光量子产率低，发射波长短，不能对线粒体局部微环境及生物活性分子进行测定等。另外，对于金纳米团簇的化学组成结构与线粒体靶向效果之间的关系目前尚缺乏系统、深入的研究。本项目旨在通过系统研究金纳米团簇粒径大小、配体化学组成结构、荷电性质等与靶向效果的关系，从而揭示线粒体靶向标记的影响因素及一般规律，用于指导设计合成具有高效线粒体靶向功能的金纳米团簇荧光探针，并最终建立线粒体靶向荧光成像方法。另外，针对线粒体局部微环境及活性物质分布特点，设计合成不同响应类型的金纳米团簇靶向荧光探针。

金纳米团簇用作荧光探针具有粒径小、毒性低、生物相容性好、易修饰、化学稳定性高、斯托克斯位移大、荧光寿命长、光谱可调谐和抗光漂白能力强等突出优点，因此在生物医学领域中显示出巨大的应用前景。本项目通过设计并筛选能够用于合成水溶性发光金纳米团簇的配体，利用可控制备技术及表面化学修饰技术调控其发光性能，系统研究了金簇发光性质及其与细胞作用的影响因素，并构建立一系列生物和药物分析新方法与新技术，为高效线粒体靶向功能的金纳米团簇荧光探针的设计合成提供了思路。分别以甲硫氨酸、6-氮杂-2-硫代胸腺嘧啶、二硫苏糖醇、N-乙酰-L-半胱氨酸、3-巯基丙酸、甲巯咪唑、脲酶、IgG等分子作为配体保护分子合成得到了一系列不同功能化的金簇，系统探讨了它们的稳定性，并将其成功应用于分析测定体系中，实现了酸性磷酸酶、碱性磷酸酶、硫酸酯酶、破伤风毒素、吡啶二甲酸、米托蒽醌、阿霉素、金刚烷胺等一系列生物和药物分子的检测。另外，研究发现6-氮杂-2-硫代胸腺嘧啶保护的金簇可作用于各种细胞的质膜上，并且在极低的浓度下，就能够在不损伤细胞的情况下对其进行长时间成像观察，具有良好的时间和空间分辨率。相关研究成果已在Analytical Chemistry、Journal of Physical Chemistry Letters、Biosensors & Bioelectronics、ACS Sensors、Journal of Hazardous Materials、ACS Applied Materials & Interfaces、Analytica Chimica Acta、Sensors and Actuators B: Chemical 等权威期刊发表论文20篇，获授权国家发明专利4项。