A triarylboron-based binuclear Zn(II) complex as a two-photon fluorescent probe for simultaneous multicolor imaging of the cell membrane, endoplasmic reticulum, and nucleolus.

The visualization of subcellular structures is critical for understanding their intracellular function. We prepared two triarylboron-based multinuclear Zn complexes, TAB-1-3Zn and TAB-2-2Zn, which can be used as fluorescent probes for nucleoside polyphosphate (NPP) and RNA because their multi Zn center can selectively combine with the phosphate side chain of NPP or RNA, accompanied by a corresponding fluorescence change. Among them, TAB-2-2Zn is more suitable than TAB-1-3Zn for live cell imaging because of its excellent cell membrane permeability resulting from amphiphilicity. Since the various membrane structures in cells are also composed of phosphoric acid bilayers, TAB-2-2Zn may also be used to image various membrane structures. Various colocalization experiments further confirmed that TAB-2-2Zn can achieve clear simultaneous imaging of the cell membrane, the endoplasmic reticulum, and the nucleolus. Graphical abstract.