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• A new peptide-based fluorescent probe DCH was synthesized. • DCH exhibited high sensitivity to Zn2+, with detection limits of 30.49 nM. • DCH was utilized for detecting Zn2+ in two real samples with high reliability. • DCH was low toxicity and could be used to monitor Zn2+ in two living cells. Zinc (Zn2+) ions play a very important role in the environment and organisms, and it is of great significance to realize the high sensitivity and selectivity detection of Zn2+ ions. Herein, a new peptide-based fluorescent probe named DCH was rationally designed and synthesized by solid phase peptide synthesis with Fmoc chemistry. DCH exhibited excellent fluorescent "turn-on" responding to Zn2+ with highly selective and exhilaratingly sensitive in aqueous media, with detection limits (LOD) as low as 30.49 nM. ESI-MS, Job's plot curves and fluorescence titration results indicated that the stoichiometric ratio between DCH and Zn2+ was 2:1. DCH could be regenerated by adding EDTA solutions to the complex formed during interaction, and indicated that DCH was promising reversibility probe. Furthermore, DCH has excellent practical application potential through two actual water sample experiments. Importantly, DCH was successfully used in monitor cellular Zn2+ and EDTA in living HK2 cells and SV-HUC-1 cells based on good biocompatibility and exciting low toxicity. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel peptide fluorescent probe DGGH was synthesized. • DGGH -Cu2+ system showed highly selective and "turn-on" response to S2−. • The detection limit of DGGH -Cu2+ for sensing S2− was calculated to be 13.7 nM. • DGGH -Cu2+ was successfully applied to monitor Cu2+ and S2− in real samples and living cells. We report a new fluorescent probe named DGGH with dansyl-labeled tripeptide (Dan-Gly-Gly-His-NH 2). DGGH showed obvious fluorescence quenching after the addition of Cu2+ ions and a 1:1 ensemble system (DGGH -Cu2+) was formed, the limit of detection was 37.9 nM. As expected, DGGH -Cu2+ ensemble system exhibited high selectivity and rapid response for S2− in 100% aqueous solutions, as a result of the addition of S2− immediately replaced Cu2+ from the DGGH -Cu2+ ensemble system. The limit of detection of the DGGH -Cu2+ ensemble for S2− was determined to be 13.7 nM. In addition, DGGH -Cu2+ has excellent detection performance within a wide pH range of 6 to 12, and its outstanding response time of less than 50s. Furthermore, we demonstrated the usability of the present approach for detecting Cu2+ and S2− in two water samples. What's more, DGGH was successfully applied to monitor Cu2+ and S2− in living LNcap cells based on good cells permeability and low toxicity. [ABSTRACT FROM AUTHOR]