A novel AIE peptide-based fluorescent probe for highly selective detection of mercury(II) ions and its application in food samples and cell imaging

[Display omitted] •An AIE-active peptide-based fluorescent probe TPE-PGH was synthesized.•TPE-PGH exhibited high selectivity and good sensitivity (58.1 nM), rapid (within 50 s) response to Hg2+ ions.•TPE-PGH was successfully used for the detection of Hg2+ in food samples with good recovery.•TPE-PGH was successfully applied in imaging of Hg2+ in living cells based on good biocompatibility.•Smartphone-assisted test strips visual assays were successfully used to evaluate and monitor Hg2+ levels. A novel peptide-based fluorescent probe TPE-PGH was firstly developed based on aggregation-induced emission (AIE) effect. The fluorescence intensity of TPE-PGH was largely ignored in the low water fraction, whereas bright blue fluorescence was observed in the high water fraction. TPE-PGH achieved high selectivity and rapid detection of Hg2+, and has excellent sensitivity to detect Hg2+ with low LOD (58.1 nM). Interestingly, TPE-PGH provided a significant color changed from dark blue to bright cyan upon binding with Hg2+ ions under UV lamp (365 nm). In addition, TPE-PGH was able to simultaneously visualize Hg2+ in living cells with different fluorescence intensities based on excellent cells permeability and low toxicity. Further, TPE-PGH exhibited high precision (RSD