A novel fluorescent probe for highly selective and sensitive detection of sulfur ions in real samples and living cells based on the tripeptide-Cu2+ ensemble system

Abstract

We report a new fluorescent probe named DGGH with dansyl-labeled tripeptide (Dan-Gly-Gly-His-NH2). 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.