A Novel Fluorescent and Colorimetric Dual-Signals Peptide-Based Probe For Sequential Recognition of Cu(Ii) and Cimetidine and its Multi-Functional Applications

Abstract

In this work, a new dual-mode response peptide-based probe named FDKSH was designed and synthesized from the raw material of 5-carboxy fluorescein, by introducing of tetrapeptide (Asp-Lys-Ser-His-NH2) for the identification of groups. FDKSH exhibited a highly selective fluorescence “on-off” response and obvious colorimetric recognition to Cu2+ in 100% aqueous media. Meanwhile, the limit of detection (LOD) was found to be 62.1 nM, which was much lower than that of stated by World Health Organization (WHO) in drinking water (30.0 μM). As a new promising cascade probe, the Cu(II)-assisted peptide ensemble probe (FDKSH-Cu2+) has very high selectivity for cimetidine by the displacement method. FDKSH-Cu2+ ensemble of cimetidine performed a good linear range of 0-50.0 μM with LOD of 63.5 nM. In addition, FDKSH was successfully used to determine Cu2+ and cimetidine in three actual water samples with satisfactory results. Additionally, the results of bioimaging experiments demonstrated that FDKSH was also successfully used for monitoring Cu2+ and cimetidine in living cells and zebrafish, and showed an excellent fluorescence imaging performance. It is worth noting that FDKSH-impregnated test strips exhibited significant fluorescence and colorimetric color changes for Cu2+ and cimetidine directly observed by the naked eye. What is more, the smartphone with RGB color recognition function provided a new method for semi-quantitative visual detection of Cu2+ and cimetidine by analyzing different concentrations of Cu2+ and cimetidine without expensive instruments.

Keywords: Dual-signals peptide-based probe, Cu(II), Cimetidine, Biological imaging, Smartphone App.