An aggregation-induced emission (AIE) ratiometric fluorescent cysteine probe with an exceptionally large blue shift

In this work, we developed a novel colorimetric and ratiometric fluorescence probe for the selective and sensitive monitoring of cysteine based on a coumarin Schiff-base platform. This probe exhibited remarkable AIE characteristics with an exceptionally large blue shift (125 nm), which showed low emission in DMSO but strong aggregation-induced emission in water solution. An excellent linear relationship of fluorescence intensity ratio (F450/F575) (R2 = 0.9922) versus Cys concentration in the range of 1–13 μM was obtained.