A novel fluorescent peptidyl probe for highly sensitive and selective ratiometric detection of Cd(ii) in aqueous and bio-samples via metal ion-mediated self-assembly. (16th October 2018)

• Record Type: Journal Article
• Authors: Jung, Kwan Ho; Oh, Semin; Park, Joohee; Park, Yu Jin; Park, See-Hyoung; Lee, Keun-Hyeung
• Is Part Of: New journal of chemistry. Volume 42:Number 22(2018)
• Page Start: 18143
• Page End: 18151
• Publication Date: 2018-10-16
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c8nj02298d
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : A fluorescent peptidyl probe based on a Cd(ii )-triggered self-assembling process was proposed for ratiometric detection for Cd(ii ) in urine and live cells. Abstract : It is still a significant challenge to synthesize ratiometric fluorescent probes for Cd 2+ ions in aqueous solutions and biosamples. In the present study, we synthesized a fluorescent peptidyl probe (1, pyrene-Cys-Gly-Pro-Cys-OH) based on a Cd 2+ -triggered self-assembling process for the ratiometric fluorescent detection of Cd 2+ in aqueous solution, urine, and live cells. The peptidyl probe (1 ) consisting of a pyrene fluorophore and a tetrapeptide receptor did not self-assemble in aqueous solutions, resulting in significant pyrene monomer emission at 395 nm. Upon addition of Cd 2+, the probes self-assembled into nanoparticles, showing significant enhancement of the excimer emission at 475 nm and a significant decrease in monomer emission at 395 nm, as revealed by fluorescence, dynamic light scattering, and transmission electron microscopy studies. Among 16 metal ions tested, only Cd 2+ induced a sensitive ratiometric response. The ratiometric response showed an excellent linearity to Cd 2+ ions, ranging from nanomolar to micromolar concentrations in aqueous solutions and urine samples. The detection limit for Cd 2+ was 22 nM ( R 2 = 0.984) and the dissociation constant was measured to be 130 pM ( R 2 = 0.997) in aqueous solutions. Two thiol groups and a C-terminal carboxylic acid group of the peptide receptor of1 play a critical role in binding with Cd 2+ . Furthermore, the probe penetrated live cells and detected intracellular Cd 2+ by ratiometric responses. The specific metal ion-induced self-assembly of peptidyl probes could be a novel platform for the development of fluorescent detection methods for metal ions in aqueous samples and biosamples.