An off-on fluorescent probe for specifically detecting cysteine and its application in bioimaging

• This off-on fluorescent probe can specifically detect cysteine.
• The interaction between probe 1 and Cys in solution was studied in detailed.
• The probe can be applied in bioimaging.

Developing effective methods to specifically detect and image cysteine in vivo has become an increasingly important area of research. Here, we synthesized and characterized two isomers of 1,8-Naphthalimide derivatives (1 and 2), and result showed 1 is a fluorescent probe for selectively detecting cysteine over other relevant biological species based on Michael addition reaction. 1 can detect cysteine by fluorescence spectrometry with a detection limit of 0.064 μmol/L and can be used for detection of cysteine in living cells. The Michael addition mechanism of the reaction between 1 and cysteine was confirmed by MS and NMR spectra.

Figure optionsDownload as PowerPoint slideBased on the Michael addition reaction of thiol with the CC bond under mild conditions, we herein report a new Cys fluorescent probe which features a rapid signal response time, a good linearity range and a low detection limit. The potential application of this new fluorescent probe was demonstrated by fluorescent imaging of Cys in living cells.