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Abstract：
This study explores the synthesis and characterization of aggregation-induced emission enhancement (AIEE)-active gold nanoclusters (AuNCs), focusing on their near-infrared luminescence properties and potential applications in biological imaging. These AIEE-active AuNCs were synthesized via the NaBH4-mediated reduction of HAuCl4 in the presence of peptides. We systematically investigated the influence of the peptide sequence on the optical features of the AuNCs, highlighting the role of glutamic acid in enhancing their quantum yield (QY). Among the synthesized peptide-stabilized AuNCs, EECEE-stabilized AuNCs exhibited the maximum QY and a pronounced AIEE effect at pH 5.0, making them suitable for the luminescence imaging of intracellular lysosomes. The AIEE characteristic of the EECEE-stabilized AuNCs was demonstrated through examinations using transmission electron microscopy, dynamic light scattering, zeta potential analysis, and single-particle imaging. The formation of the EECEE-stabilized AuNCs was confirmed by size-exclusion chromatography and mass spectrometry. Spectroscopic and electrochemical examinations uncover the formation process of EECEE-stabilized AuNCs, comprising EECEE-mediated reduction, NaBH4-induced nucleation, complex aggregation, and subsequent cluster growth. Furthermore, we demonstrated the utility of these AuNCs as luminescent probes for intracellular lysosomal imaging, leveraging their pH-responsive AIEE behavior. Additionally, cyclic arginylglycylaspartic acid (RGD)-modified AIEE dots, derived from cyclic RGD-linked peptide-induced aggregation of EECEE-stabilized AuNCs, were developed for single- and two-photon luminescence imaging of αvβ3 integrin receptor-positive cancer cells.
摘要：
本研究探索了聚集诱导发射增强（AIEE）活性金纳米簇（AuNC）的合成和表征，研究了其近红外发光特性及其在生物成像中的潜在应用。这些AIEE活性AuNC是在肽存在下通过NaBH4介导的HAuCl4还原合成的。我们系统地研究了肽序列对AuNC光学特征的影响，强调谷氨酸在提高量子产率(QY)中的作用。在合成的肽稳定的AuNC中，EECEE稳定的AuNC在pH5.0时表现出最大的QY和明显的AIEE效应，使其适用于细胞内溶酶体的发光成像。通过使用透射电子显微镜的检查证明了EECEE稳定的AuNC的AIEE特性，动态光散射,zeta电位分析，和单粒子成像。通过尺寸排阻色谱和质谱确认EECEE稳定的AuNC的形成。光谱和电化学检查揭示了EECEE稳定的AuNC的形成过程，包括EECEE介导的还原，NaBH4诱导的成核，复杂聚合，以及随后的集群增长。此外，我们证明了这些AuNC作为细胞内溶酶体成像的发光探针的实用性，利用其pH响应性AIEE行为。此外,环状精氨酰甘氨酰天冬氨酸（RGD）修饰的AIEE点，源自环状RGD连接肽诱导的EECEE稳定的AuNC聚集，已开发用于αvβ3整合素受体阳性癌细胞的单光子和双光子发光成像。
