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A potential fluorescent probe, N'-acetyl-2-((4-methyl-2-oxo-2H-chromen-7-yl)oxy)acetohydrazide (HMC1) was designed on the basis of photoinduced electron transfer (PET) and synthesized using cheap starting materials. HMC1 was found to be highly efficient as a Cu 2+ ion quencher with a detection limit of 0.64 μM (~ 40 ppb). The binding mode of HMC1 towards Cu 2+ was evaluated by 1 H NMR, LC-MS and FT-IR techniques. In addition, cellular imaging studies further exhibited that HMC1 could be used an intracellular turn-off fluorescent chemosensor for Cu 2+ in living cells. [ABSTRACT FROM AUTHOR]

The development of sensitive chromogenic chemosensors for sensing Cu 2+ has been receiving much attention in recent years because of their potential application in clinical biochemistry and the environment studies. Numerous chemosensors have been developed for selective recognition of different species on the basis of host–guest interactions such as hydrogen-bonding, electrostatic force, metal–ligand coordination, hydrophobic and van der Waals force of interactions. The simple and rapid sensing of Cu 2+ ions in biological and environmental systems is desirable and the development of selective and sensitive imaging tools capable of monitoring Cu 2+ ions rapidly has attracted considerable attention. Fluorescent chemosensors have served as useful tool for detecting metal ions owing to their intrinsic sensitivity, selectivity and capacity for rapid, real-time monitoring. Small-molecule fluorescent probes can make use of selective, bio-orthogonal chemistries to report on specific analytes in cells and in more complex biological specimens. This review presents a survey of strategies for using small-molecule fluorescent probes to detect Cu 2+ ions which cover UV to NIR regions such as anthracene, pyrene, quinoline, quinazoline, dansyl, naphthalimide, rhodamine, fluorescein, BODIPY and cyanine dyes. [ABSTRACT FROM AUTHOR]

A new on-off fluorescent probe 1 for Cu 2+ based on Schiff base compound was designed and synthesized by one-step reaction. The single probe 1 exhibited strong green fluorescence emission. A fluorescence quenching effect and faint color change were observed as soon as the Cu 2+ was added to the probe system in H 2 O/EtOH (v/v = 8:2, HEPES buffer, 0.05 M, pH = 7.4) solution. Other common metal cations did not cause the changes in the fluorescence and color of the probe 1. The optical properties were studied by the fluorescence emission and UV–Vis spectra. Meanwhile, the geometry optimizations of probe 1 and the [1-Cu 2+ ] coordination complexes were also carried out by DFT using the Gaussian 09 program, in which the B3LYP function was used. Based on experimental measurement and theoretical analysis, we can know that the combination ratio of the probe and Cu 2+ is 2:1 and the limit of detection (LOD) is as low as 5.3 × 10 −9 M Besides, the probe 1 was also used to analyze the Cu 2+ in living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel colorimetric and fluorescent chemosensor based on diaminopyrimidine (DAPCS) was designed and synthesized. • DAPCS was applied for the highly selective and ultra-sensitive detection of Cu2+ ion in aqueous media and living cell. • The probe DAPCS for Cu2+ showed a linear correlation, and LOD was calculated as 0.014 µM. • DAPCS-based test strips were fabricated and applied to the detection of Cu2+ ions in solutions. In this paper, a new and effective diaminopyrimidine-based chemosensor (DAPCS) was developed for the highly selective and ultra-sensitive detection of Cu2+ ion in aqueous media and living cell. Characterization and structure determining of DAPCS was determined by UV–Vis, FTIR and NMR analyses. It is observed that DAPCS and Cu (II) forms a ligand to metal charge transfer (LMCT) complex which produces distinguishable red color. The results also indicate that the DAPCS easily interacts with Cu2+ ion to form a 1:1 stoichiometry complex (DAPCS -Cu2+), resulting in a bathochromic shift in absorption maximum (429 nm to 449 nm) and remarkable quenching fluorescence intensity at the wavelength of 501 nm in DMSO-H 2 O solution. Furthermore, the detection limit of DAPCS towards Cu2+ was calculated to be 3.19 µM. Meanwhile, DAPCS was applied as fluorescent probe for detection of Cu2+ ions with the detection limit of 0.014 µM. The optimal pH range of probe DAPCS for quantitative analysis of Cu2+ ions was 9–11, which renders it suitable for detection of Cu2+ under physiological conditions. Additionally, the DAPCS could be applied to detect Cu2+ in real water samples and in HeLa cells, indicating the practical uses of DAPCS in real analyses. [ABSTRACT FROM AUTHOR]

Highly sensitive and selectivite detection of copper ions (Cu2+) and hydrogen sulfide (H 2 S) have become important research topics due to the potential harmful impacts of these chemicals to human health and the environment. In this study, we report the synthesis of a dual-functional peptide-based probe L (FITC-AhxSerSerHis), designed to mimic a copper-sulfur metalloprotein, and capable of continuous detection of Cu2+ and S2- based on colorimetric and fluorescent methods. The new probe L displayed excellent "turn off" fluorescence response and good selectivity for Cu2+ ions via a modification of the tripeptide and fluorescein isothiocyanate group, and produced an obvious color change visible to the naked eye. Furthermore, as an excitable probe, the L -Cu complex could continuously detect S2- with high selectivity and sensitivity in 100% aqueous buffered solutions. The detection limits for fluorescence titration measurements, calculated using the equation 3σ/k, were 76.7 nM (Cu2+) and 27.2 nM (S2-), which were well below U.S. EPA safety levels. In addition, L could be cycled to alternately detect Cu2+ and S2-, thereby making it a promising reversible probe. Moreover, L was successfully applied to monitoring Cu2+ and S2- in live RKO cells through fluorescence imaging, exhibiting low cytotoxicity and good cell permeability. ga1 • Novelty peptide-based probe (L) was developed for Cu2+ and S2- with colorimetric and fluorescent. • The low detection limits of Cu2+ and S2- were 76.7 nM and 27.2 nM, respectively. • L could be recycled many times during the detection of Cu2+ and S2- as reversible probe. • L was successfully applied for sensing Cu2+ and S2- in living cells. [ABSTRACT FROM AUTHOR]