Gold nanoclusters (AuNCs) with well-defined atomically precise structures present promising emissive prospects for excellent biocompatibility and optical properties. However, the relatively low luminescence efficiency in solutions for most AuNCs is still a perplexing issue to be resolved. In this study, a facile supramolecular strategy was developed to rigidify the surface of FGGC-AuNCs by modifying transition rates in excited states via host–guest self-assembly between cucurbiturils (CBs) and FGGC (Phe–Gly–Gly–Cys peptide). In aqueous solutions, CB/FGGC-AuNCs presented an extremely enhanced red phosphorescence emission with a quantum yield (QY) of 51% for CB[7] and 39% for CB[8], while simple FGGC-AuNCs only showed a weak emission with a QY of 7.5%. Furthermore, CB[7]/FGGC-AuNCs showed excellent results in live cell luminescence imaging for A549 cancer cells. Our study demonstrates that host–guest self-assembly assisted by macrocycles is a facile and effective tool to non-covalently modify and adjust optical properties of nanostructures on ultra-small scales.

中文翻译：

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葫芦素增亮水中的纳米金簇

具有明确定义的原子精确结构的金纳米团簇（AuNCs）具有出色的生物相容性和光学性能，具有广阔的发展前景。然而，大多数AuNC的解决方案中相对较低的发光效率仍然是一个亟待解决的难题。在这项研究中，一个浅显的超分子战略开发的激发态修改转换率FGGC-AuNCs表面僵化通过葫芦（CBs）和FGGC（Phe-Gly-Gly-Cys肽）之间的宿主-客体自组装。在水溶液中，CB / FGGC-AuNCs表现出极大的红色磷光发射，CB [7]的量子产率（QY）为51％，CB [8]的量子产率为39％，而简单的FGGC-AuNCs仅显示弱发射。 QY为7.5％。此外，CB [7] / FGGC-AuNCs在A549癌细胞的活细胞发光成像中显示了出色的结果。我们的研究表明，由大环化合物辅助的宿主与客体自组装是一种便捷有效的工具，可以非共价地修饰和调节纳米结构的超小尺度光学特性。