High selective and sensitive detection of Zn(II) using tetrapeptide-based dansyl fluorescent chemosensor and its application in cell imaging

Abstract

The zinc ions (Zn2+) play extremely irreplaceable role in the organism and the environment, the design and synthesis of a biomolecule-based fluorescence chemosensor for the detection of Zn2+ with high sensitivity is very important. Herein, a novel tetrapeptide-based dansyl fluorescent “turn-on” response chemosensor (L) has been designed and synthesized by solid phase peptide synthesis (SPPS). As designed, L can detect Zn2+ ions with specifically and sensitively based on photo-induced electron transfer (PET) mechanism in 100% aqueous solutions, and other metal ions do not interfere with Zn2+ ions recognition. The stoichiometric ratio of L with Zn2+ ions was 2:1, which matches with fluorescence titration and Job-plot assay. In addition, the reversibility and circularly process of the detection of L was confirmed by adding bonding agent Na2EDTA. Moreover, L exhibits excellent biocompatibility and low biotoxicity with the limit of detection (LOD) for Zn2+ about 18 nM, and has been successfully utilized for fluorescence imaging of Zn2+ ions in living HeLa cells under physiological conditions.