Highly selective and sensitive detection of Zn(II) and Cu(II) ions using a novel peptide fluorescent probe by two different mechanisms and its application in live cell imaging.

Abstract

Metalloproteins are often a useful template for the design and development of peptide fluorescent probes. Herein, we report a novel and simple fluorescent probe L comprised of tetrapeptide and dansyl groups by the solid phase peptide synthesis (SPPS). As a multifunctional analytical probe, L exhibited a highly selective "turn-on" fluorescent response to zinc ions, and a selective "turn-off" fluorescent response to copper ions at an excitation wavelength of 330 nm. The high sensitivity of L was made possible photo-induced electron transfer (PET), and L exhibited very low detection limits for Zn2+ and Cu2+ of 4.9 nM and 15 nM in 100% aqueous solutions, respectively. Furthermore, L displayed very low biotoxicity and excellent cell permeability, and was successfully used for detection of Zn2+ and Cu2+ in living HeLa cells based on two different mechanisms. We believe that the probe L may have many potential applications in environmental and biological research.