A phosphorescent silver(I)–gold (I) cluster complex that specifically lights up the nucleolus of living cells with FLIM imaging

• Published in: Biomaterials Vol. 34; no. 17; pp. 4284 - 4295
• Main Authors: Chen, Min, Lei, Zhen, Feng, Wei, Li, Chunyan, Wang, Quan-Ming, Li, Fuyou
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.06.2013
• Subjects: Advanced Basic Science; Biological Transport; Cell Cycle; Cell Death; Cell Line, Tumor; Cell Nucleolus - metabolism; Cell Survival; Dentistry; Endocytosis; FLIM imaging; Flow Cytometry; Gold - chemistry; Humans; Imaging, Three-Dimensional; Kinetics; Luminescent Measurements; Microscopy, Confocal; Microscopy, Fluorescence - methods; Nucleolus; Photobleaching; Selective staining; Silver - chemistry; Silver(I)–gold (I) cluster complex; Spectrophotometry, Atomic; Staining and Labeling; Temperature; Silver(I)–gold (I) cluster complex; Selective staining; FLIM imaging; Nucleolus
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/j.biomaterials.2013.02.032

Abstract The phosphorescent silver(I)–gold(I) cluster complex [CAu6 Ag 2dppy 6 ](BF4 )4 ( N1 ) selectively stains the nucleolus, with a much lower uptake in the nucleus and cytoplasm, and exhibits excellent photostability. This Ag–Au cluster, which has a photoluminescent lifetime of microseconds, is particularly attractive as a probe in applications of time-gated microscopy. Investigation of the pathway of cellular entry indicated that N1 permeates the outer membrane and nuclear membrane of living cells through an energy-dependent and non-endocytic route within 10 min. High concentrations of N1 in the nucleolus have been quantified by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and transmission electron microscopy coupled with an energy dispersive X-ray analysis (TEM-EDXA), which also helped to elucidate the mechanism of the specific staining. Intracellular selective staining may be correlated with the microenvironment of the nucleolus, which is consistent with experiments conducted at different phases of the cell cycle. These results prove that N1 is a very attractive phosphorescent staining reagent for visualizing the nucleolus of living cells.