Peptide-based fluorescent probe with large Stokes shift for specific sequential detection of copper (II) ions and histidine: Smartphone device, real samples, test strips and bioimaging applications

• Published in: Microchemical journal 2024-12, Vol.207, p.111728, Article 111728
• Main Authors: Wang, Peng, Cao, Xinlin, Xue, Shirui, Wang, Zhijie, Zhou, Yi, Wu, Jiang
• Format: Article
• Language: English
• Subjects: Bio-imaging; Cu(II); L-Histidine; Peptide-based fluorescent probe; Semi-quantitative and visual detection
• ISSN: 0026-265X
• DOI: 10.1016/j.microc.2024.111728

[Display omitted] •A peptide-based fluorescent probe DNH was developed for the specific sequential detection of Cu(II) and L-His.•The detection limits for Cu(II) and L-His were notably low at 19.6 nM and 22.8 nM, respectively.•DNH was effectively employed for imaging Cu(II) and L-His in living cells and zebrafish.•DNH facilitated the recognition of Cu(II) and L-His in test strip applications.•A smartphone App was successfully utilised for the semi-quantitative and visual detection of Cu(II) and L-His. A novel and facile fluorescent probe, DNH, was developed based on a dipeptide backbone (Asn-His-NH2) labelled with a dansyl fluorophore. DNH exhibited significant advantages in detecting Cu2+ based on the paramagnetic quenching mechanism, including satisfactory water solubility (100 % aqueous medium), a large Stokes shift (230 nm), excellent anti-interference capability (no interference), a low detection limit (19.6 nM), rapid response time (within 30 s) and a wide pH range (7–12). Employing a displacement approach, the DNH-Cu2+ ensemble showed strong fluorescence enhancement upon recognition of L-His with outstanding selectivity, and the detection limit for the DNH-Cu2+ ensemble with respect to L-His was calculated at 22.8 nM. Notably, DNH demonstrated favourable reversibility for at least seven cycles with minor changes in fluorescence intensity when Cu2+ and L-His were added alternately. Moreover, DNH exhibited excellent low cytotoxicity and good biocompatibility, and was utilised as an outstanding probe for the sequential determination of Cu2+ and L-His in living cells and zebrafish. DNH was successfully used to determine Cu2+ and L-His in three actual water samples with good recovery and accuracy. In addition, DNH was applied to filter paper to develop visual test strips for the rapid and high-efficiency analysis of Cu2+ and L-His. Furthermore, the semi-quantitative visual monitoring of Cu2+ and L-His was achieved by developing a smartphone colour recogniser into a portable analytical device, achieving low detection limits of 0.49 μM and 0.63 μM, respectively. Given these attributes, DNH presents itself as a promising peptide-based fluorescent probe, showcasing considerable potential for real-time visual monitoring of Cu2+ and L-His in various environmental and biological settings.