title: A phosphorescent silver(I)-gold (I) cluster complex that specifically lights up the nucleolus of living cells with FLIM imaging.
abstract: The phosphorescent silver(I)-gold(I) cluster complex [CAu6Ag2(dppy)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.
authors.affiliation: Department of Chemistry & Institute of Biomedicine Science, Fudan University, Shanghai 200433, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.forename: Zhen
authors.initials: Z
authors.lastname: Lei
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.forename: Chunyan
authors.initials: C
authors.lastname: Li
authors.forename: Quan-Ming
authors.initials: QM
authors.lastname: Wang
authors.forename: Fuyou
authors.initials: F
authors.lastname: Li
mesh_terms: D001692:Biological Transport; D002453:Cell Cycle; D016923:Cell Death; D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000378:metabolism*; D002470:Cell Survival; D004705:Endocytosis; D005434:Flow Cytometry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007700:Kinetics; D008163:Luminescent Measurements; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence / Q000379:methods*; D038761:Photobleaching; D012834:Silver / Q000737:chemistry*; D013054:Spectrophotometry, Atomic; D013194:Staining and Labeling; D013696:Temperature
chemical_list: D012834:Silver; D006046:Gold