Selective and sensitive detection of Zn(II) ion using a simple peptide-based sensor

- A novel short peptide-based chemosensor is synthesized and used for the detection of Zinc ion both in vitro and living cells.
- The chemosensor L displays high selectivity and sensitivity with the detection limit for Zn(II) ion measured to be 82 nM.
- The chemosensor L shows a fine performance in cell fluorescence imaging.
- The binding mode was predicted by molecular modelling between peptide-based chemosensor HL and Zinc ion.

The development of biocompatible chemosensors is becoming increasingly important for chemical analyses in environmental sampling, the food industry, and clinical medicine. Many current chemosensors have limited utility as they represent potential secondary pollutants. To circumvent this problem, researchers are evaluating peptide-based fluorescent chemosensors because of their well-established synthesis protocols, good biological compatibility, and generally low cytotoxicity, which makes them suitable for bioimaging. In this study, we report the development of a peptide-based fluorescent chemosensor HL (fluorophore-Cys-Pro-Gly-His) for divalent zinc ions (Zn2+). The objective of this study was to select a suitable peptide sequence and associated fluorophore exhibiting high selectivity and sensitivity to Zn2+-binding, and enhanced fluorescent response. Results of this study, both in vitro and in living cells, indicated that HL exhibited high selectivity and sensitivity for Zn2+, with a limit of detection (LOD) of about 82 nM. The sensor also exhibited very low cell cytotoxicity and strong fluorescence emission in living cells, which indicates that it may find application as a novel chemosensor for selective Zn2+ detection in biological environments.