A novel peptide-based fluorescent probe for highly selective detection of mercury (II) ions in real water samples and living cells based on aggregation-induced emission effect.

A new fluorescent probe TPE-GHK was synthesized containing a tetrastyrene (TPE) derivative as fluorophore and classical tripeptide (Gly-His-Lys-NH) as a receptor based on the aggregation-induced emission (AIE) mechanism. TPE-GHK displayed high selectivity and rapid fluorescent "turn-on" response to Hg among other competitive metal ions. The 2:1 complex binding mechanism of TPE-GHK toward Hg was verified by fluorometric titration, Job's plots, and ESI-HRMS spectra. The fluorescent emission showed a good linear response in the range of 0-1.0 μM with the low detection limit of 28.6 nM. Meanwhile, TPE-GHK exhibited the excellent biocompatibility and low toxicity and was successfully applied in monitoring Hg in living CAKI 2 cells, which demonstrated its potential application in environment and biological science. More importantly, TPE-GHK could be used to detect Hg in two real water samples and also was successfully designed as test strips.