A highly selective and sensitive Zn2+ fluorescent sensor based on zinc finger-like peptide and its application in cell imaging

Developing new chemosensors for detection of Zn2+ has attracted great attentions because of the important roles of Zn2+ in biological systems, and it will produce toxic effects with an excessive intake of zinc ion. Metalloproteins are often used as an effective template for the design and development of peptide-based fluorescent sensors. In this study, we designed a new and simple ratiometric fluorescent sensor for Zn2+, which was based on a zinc finger-like peptide and labeled with a dansyl group, i.e., Dansyl-His-GlnArg-Thr-His-Trp-NH2 (D-P6), by using solid phase peptide synthesis (SPPS). The dimeric peptide has a high affinity for Zn2+ over other metal ions, as indicated by spectroscopic studies, as well as molecular modeling. Remarkably, the sensor exhibited a highly selective and sensitive ratiometric fluorescent response to Zn2+ by fluorescent resonance energy transfer effect between tryptophan residue and fluorophore dansyl group, with a very low detection limit of 33 nM in aqueous solution. Furthermore, the sensor displayed a very low biotoxicity, which allows successful detection of Zn2+ in living HeLa cells. We believe that the new sensor may have potential applications in biological science. (C) 2021 Elsevier B.V. All rights reserved.