Zhou Ting, Zang Luyao, Zhang Xia, Liu Xia, Qu Zijie, Zhang Guodong, Wang Xiufeng, Wang Fang, Zhang Zhiqing
Department of Chemistry, College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Molecules. 2024 Dec 20;29(24):6011. doi: 10.3390/molecules29246011.
Gold nanoclusters (AuNCs) have been widely investigated because of their unique photoluminescence properties. However, the applications of AuNCs are limited by their poor stability and relatively low fluorescence. In the present work, we developed nanocomposites (L-Cys-AuNCs@ZIF-8) with high fluorescence and stability, which were constructed by encapsulating the water-dispersible L-Cys-AuNCs into a ZIF-8 via Zn-triggered growth strategy without high temperature and pressure. The maximum emission wavelength of the L-Cys-AuNCs@ZIF-8 composite was at 868 nm, and the fluorescence intensity of L-Cys-AuNCs@ZIF-8 was nearly nine-fold compared with L-Cys-AuNCs without the ZIF-8 package. The mechanism investigation by fluorescence spectroscopy and X-ray photoelectron spectroscopy showed that L-Cys-AuNCs@ZIF-8 impeded ligand rotation, induced energy dissipation, and diminished the self-quenching effect, attributing to the spatial distribution of L-Cys-AuNCs. Based on the high fluorescence efficiency of L-Cys-AuNCs@ZIF-8, a "signal off" detective platform was proposed with copper ions as a model analyte, achieving a sensitive detection limit of Cu at 16.7 nM. The quenching mechanism was confirmed, showing that the structure of the L-Cys-AuNCs@ZIF-8 nanocomposites was collapsed by the addition of Cu. Attributing to the strong adsorption ability between copper ions and pyridyl nitrogen, the as-prepared L-Cys-AuNCs@ZIF-8 was shown to accumulate Cu, and the Zn in ZIF-8 was replaced by Cu.
金纳米团簇（AuNCs）因其独特的光致发光特性而受到广泛研究。然而，AuNCs的应用受到其稳定性差和荧光相对较低的限制。在本工作中，我们通过锌触发生长策略在无需高温高压的情况下将水分散性L-半胱氨酸修饰的金纳米团簇（L-Cys-AuNCs）封装到ZIF-8中，制备了具有高荧光和稳定性的纳米复合材料（L-Cys-AuNCs@ZIF-8）。L-Cys-AuNCs@ZIF-8复合材料的最大发射波长为868 nm，与未包裹ZIF-8的L-Cys-AuNCs相比，L-Cys-AuNCs@ZIF-8的荧光强度提高了近9倍。通过荧光光谱和X射线光电子能谱进行的机理研究表明，L-Cys-AuNCs@ZIF-8阻碍了配体旋转，诱导了能量耗散，并减少了自猝灭效应，这归因于L-Cys-AuNCs的空间分布。基于L-Cys-AuNCs@ZIF-8的高荧光效率，提出了以铜离子为模型分析物的“信号关闭”检测平台，实现了对铜的灵敏检测限为16.7 nM。淬灭机理得到证实，表明添加铜会导致L-Cys-AuNCs@ZIF-8纳米复合材料的结构坍塌。由于铜离子与吡啶氮之间具有很强的吸附能力，所制备的L-Cys-AuNCs@ZIF-8能够积累铜，并且ZIF-8中的锌被铜取代。
