Using Fluorescence On/Off to Trace Tandem Nanofiber Assembly/Disassembly in Living Cells

To track an intact biological process inside cells, continuous showing of the assembly/disassembly process is needed and fluorescence is advantageous in characterizing these processes. However, using fluorescence on/off' to observe a sequential assembly/disassembly process in living cells has not been reported. Herein, we rationally designed a probe PEA-NBD-Yp and employed its fluorescence on/off' to trace tandem assembly/disassembly of nanofibers in living HeLa cells. In vitro experiments validated that PEA-NBD-Yp could be efficiently dephosphorylated by ALP to yield PEA-NBD-Y, which self-assembled into nanofibers with the NBD fluorescence on. Also, the PEA-NBD-Y nanofiber was disassembled by GSH, accompanied by fluorescence off. Living cell imaging (together with ALP-inhibition or GSH-blocking) experiments sequentially showed the self-assembling nanofibers on the cell outer membrane with fluorescence on (On(1)), translocated inside cells (On(2)), and disassembled by GSH with fluorescence off (Off(2)). We anticipate that our strategy of one probe conferring temporal on/off' fluorescence signals might provide people with a new tool to deeply understand a biological event in living cells in the near future.

Automated summary

Researchers successfully designed a new fluorescence probe to track the assembly and disassembly process of nanofibers in living cells.