Selectivity For Cu2 Research Articles

Selective Cu2+ detection by a novel fluorescence hydrazone – Base probe in aqueous media

This article describes the novel hydrazone derivatives bearing chromeno[2,3-c]pyrazole heterocycles synthesis via pyrazol-3-one elimination and the properties of their fluorescence emission. The photophysical properties of the novel dyes were studied in the presence of different solvents, and 31 various ions, which demonstrated hydrazone 4b showed a distinct response toward Cu2+ in rather aqueous media with a good limit of detection. This probe forms a 1:2 complex with Cu2+, and fluorescence enhancement occurs by CN isomerization inhibition. Also, the results exhibited that 4b with moderate cytotoxicity is a simple and valuable probe for selective fluorescence sensing of Cu2+ ions in both experimental and real samples.

An innovative colorimetric platform for the low-cost and selective identification of Cu(II), Fe(III), and Hg(II) using GQDs-DPA supported amino acids by microfluidic paper-based (µPADs) device: Multicolor plasmonic patterns

This study reports the synthesis of functional graphene quantum dots (GQDs) through the thermal pyrolysis of D-penicillamine (DPA) and citric acid towards water treatment. For the first time, a novel type of highly fluorescent probe for selective Cu2+ detection among 26 types of metal ions which considerably enhance the fluorescence intensity of GQD. Furthermore, the recognition effects can be strengthen addition of amino acids owing to raise the electron density of the system and boos the accumulation profile of the sensing molecules. This simple fluorescent probe was applied for facile metal ions recognition in human urine samples, as well as environmental fluids. The proposed DPA-GQDs supported amino acids respond to Cu2+, Hg2+, and Fe3+, with high sensitivity. The intensity of the fluorescence histogram of this probe significantly diminished in exposure to metal ions such as, Cu(II), Hg(II), and Fe(III). Moreover, in our work, microfluidic paper-based (µPADs) was fabricated through a facile and a cost-effective method. Cu2+ can selectively be recognized by GQD-DPA on the paper-based sensors by naked-eye. The functionalized DPA-GQDs is an excellent alternative to previously reported fluorescent probes for sensing, bio-labeling, and other biological usages in aqueous solution. Its nitrogen and oxygen-rich groups can coordinate with Cu2+ and cause to an apparent fluorescence quenching by the non-radiative electron-transmission. The technique presented in this paper is economical and simple in design, and provides a "mix-and-sense" protocol with no need to chemical- or dye-modifications. Our proposed Cu2+ sensing probe exhibits linear response in the concentrations ranging from 0.001 ppm to 5 ppm, with a lower limit of quantitation (LLOQ) of 0.1 ppm in both environmental fluids, and human urine samples. The enhanced color uniformity, the low instrumental needs of the stamp, and disposability of μPADs enable the application of the suggested paper-based device for the commercial diagnostics biosensor.

Novel phenylalanine derivative-based turn-off fluorescent chemosensor for selective Cu2+ detection in physiological pH

A novel and unnatural amino acid-based phenylalanine derivative bearing dansyl and benzoxazole moieties (DPB) as a side chain has fine-tuned fluorometric/colorimetric chemosensor was synthesized and characterized through various spectroscopic techniques. It was verified with 16 other competing alkali, alkali-earth, and transition metal ions but it was selectively quenched the Cu2+ ion in aqueous organic media with physiological pH (DMSO/H2O, 1:1, v/v, pH 7.4). The binding interaction was proved as 1:1 by Job’s plot method and the LOD value was found as 3.0 μM which is a much lower value than WHO and EPA guideline value. A naked eye color change was observed with Cu2+ ion, it induces a light yellow to light brown color with a large Red Shift value (307–539 nm) in emission spectra. The utilization of this sensor for water analysis also performing well with a high-level recovery rate of up to 99.92%. The encouraging photophysical results revealed that this probe DPB will act very well by selectively and sensibly as a “turn of” chemosensor towards Cu2+ ion.

Development of a method for the detection of Cu2+ in the environment and live cells using a synthesized spider web-like fluorescent probe

A macrocyclic Schiff base fluorescent probe [1,2-phenylenediamine-2,6-pyridinedialdehyde macrocyclic Schiff base] (BP-MSB) based on 2,6-pyridinedialdehyde was synthesized for use in the detection of Cu2+ in environmental water samples and live cells imaging by the method of specific recognition. The free fluorescent probe BP-MSB shows strong fluorescence in DMSO/H2O. The probe shows high sensitivity and selectivity for Cu2+ through “turn-off” fluorescence response in DMSO/H2O buffer solution (pH = 6.5), with a detection limit of 0.83 nM, which is far below the maximum allowable drinking water content of 20.0 μM specified by the US Environmental Protection Agency. The BP-MSB fluorescence quenching method was used for the determination of Cu2+ in Xiang Jiang water samples and tap-water. Furthermore, addition of the same number of moles of ethylene diamine tetraacetic acid (EDTA) can realize the reversible recognition of Cu2+ by the probe BP-MSB. Most importantly, the fluorescence imaging of live cells after incubation of BP-MSB with GM12878 cells showed good imaging performance, confirming the sensitivity of the fluorescent probe BP-MSB in vivo. The probe was also used to form an analog logic gate. This probe has the advantages of good stability, simple operation and high selectivity, which provides a broad prospect for environmental monitoring, intracellular detection and practical application of POCT.

Aggregation-Induced Emission-Active Fluorescent Polymer: Multi-Targeted Sensor and ROS Scavenger.

A multi-functional polymer with aggregation-induced emission (AIE)-active salicylaldehyde azine (SA) functionality and reactive oxygen species (ROS)-responsive thioether groups is readily prepared via thiol-ene click polymerization of SA derivative diacrylate monomer, poly(ethylene glycol) diacrylate, and 3,6-dioxa-1,8-octanedithiol. The obtained AIE-active polymer exhibited an unexpected strong emission in amide solvents compared to that in other common organic solvents that was dramatically decreased by adding a trace amount of water, suggesting that the polymer could be utilized as a water trace indicator in amide solvents. In the backbone, the PEG segments make the polymer well dispersed in water and the ROS-responsive thioether groups enable this polymer as a promising ROS scavenger, with embedded SA moieties as a fluorescent indicator for the hemolysis determination. Due to the ability of SA moieties to complex with Cu2+, this AIE polymer can also be utilized as a fluorescent sensor for selective Cu2+ detection in real-world water samples. Thus, this multi-functional polymer is anticipated to be well applied in biological and environmental applications.

Novel sampangine derivatives as potent inhibitors of Cu2+-mediated amyloid-β protein aggregation, oxidative stress and inflammation

A series of 11-substituted sampangine derivatives have been designed, synthesized, and tested for their ability to inhibit cholinesterase. Their chelating ability and selectivity for Cu2+ over other biologically relevant metal ions were demonstrated by isothermal titration calorimetry. Their blood-brain barrier permeability was also tested by parallel artificial membrane permeation assay. Among the synthesized derivatives, compound 11 with the strong anti-acetylcholinesterase activity, high blood-brain barrier penetration ability and high binding affinity to Cu2+ was selected for further research. Western blotting analysis, transmission electron microscopy, DCFH-DA assay and paralysis experiment indicated that compound 11 suppressed the formation of Cu2+-Aβ complexes, alleviated the Cu2+ induced neurotoxicity and inhibited the production of ROS catalyzed by Cu2+ in Aβ42 transgenic C. elegans. Moreover, compound 11 also inhibited the expressions of proinflammatory cytokines, such as NO, TNF-α, IL-6 and IL-1β, induced by Cu2+ + Aβ1–42 in BV2 microglial cells. In general, this work provided new insights into the design and development of potent metal-chelating agents for AD treatment.

Construction of a novel ion imprinted film to remove low concentration Cu2+ from aqueous solution

To develop a green approach to ion capturing and separation, an electrochemically assisted imprinting and elution strategy was proposed. Novel ion imprinted film (Cu2+-IIF) was synthesized by combining ion imprinting technology with electrochemically switched ion exchange technology for removal of low concentration Cu2+ from aqueous solution. Cu2+-IIF was prepared by using Cu2+ as template ion, potassium ferrocyanide as doping agent, pyrrole as cross-linker and conductor. To enhance the ability to remove Cu2+ at low concentration, adsorption and reduction were integrated. The morphologies and microstructures of samples were characterized by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transformation infrared spectrometry and X-ray photoelectron spectroscopy. The removal ability and selectivity of Cu2+ were tested. The results show that more than 90% of Cu2+ at the concentration of 5 ppm was removed, thus meeting the requirement for direct emission. The adsorption capacity reaches 7.57 mg g−1 at initial Cu2+ concentration of 5 ppm. The selectivity factor of Cu2+ with respect to Cd2+, Zn2+ and Ni2+ was 49.27, 26.52 and 30.16, respectively. The removal capacity of Cu2+-IIF remained 95.13% after five cycles.

An ultra-sensitive selective fluorescent sensor based on a 3D zinc-tetracarboxylic framework for the detection and enrichment of trace Cu2+ in aqueous media.

Herein, a novel and fluorescent zinc-organic framework sensor [Zn3(μ3-Hbptc)2(μ2-4,4'-bpy)2(H2O)4]n·2nH2O (1) (H4bptc = 2,3,3',4'-biphenyl tetracarboxylic acid, 4,4'-bpy = 4,4'-bipyridine) is synthesized and characterized, demonstrating its excellent fluorescence performance for Cu2+ detection and the enrichment of Cu2+ in aqueous media. The fluorescence intensity of 1 can be selectively quenched by Cu2+ in a linear range of Cu2+ concentrations of 0-0.7 μM. The limit of detection (LOD) value is as low as 32.4 nM, which is superior to those of most of the fluorescent sensors based on metal-organic frameworks (MOFs). It is also far below the maximum allowable concentration of Cu2+ in drinking water as defined by the U.S. Environmental Protection Agency (EPA) and the World Health Organization (WHO), so it is employed for the detection of Cu2+ in actual water samples. More importantly, the nature of the interaction between the active coordination site (COO-) of 1 and Cu2+ determines the quenching mechanism, that is Cu2+ in the analyte is captured by MOF 1, which has been investigated by ICP, luminescence, UV-vis, XPS, and lifetime studies. Besides, the chemosensor shows regeneration performance without the loss of performance in five consecutive cycles. So MOF 1 is a simple and convenient probe used not only for the rapid detection but also for the enrichment of trace amounts of Cu2+ in aqueous media, and the application can be further extended to a variety of environmental and biological analysis processes.

Structurally defined polythiophene-based nanoprobe for selective Cu2+ detection in living cells

Abstract Structurally defined block conjugated polymers (SDBCPs) are characterized by unique photophysical and self-assembly properties. However, the potential of SDBCP for sensing application has seldomly been exploited. Herein, we present the synthesis and application of a novel type of SDBCP, P3EPT17-b-P3ImHT33, which is comprised of regio-regular diblock polythiophene and imidazole side chains. P3EPT17-b-P3ImHT33 can self-assemble into nanofibers in DMSO via crystallization-driven self-assembly, while it self-assembles into quasi-spherical micelles in water via hydrophilic/hydrophobic phase separation. By exploiting the strong coordination interaction between Cu2+ and imidazole group, P3EPT17-b-P3ImHT33-based nanoparticles (PT–CPNs) were used as an effective fluorescent nanoprobe for the selective and sensitive detection of Cu2+. The detection limit can be down to 0.13 nM. Furthermore, fluorescence imaging studies demonstrated that PT–CPNs can efficiently detect Cu2+ in living HeLa cells.

Altering molecular polarity via assembly induced charge transfer for high selectivity detection of Cu2+

In this work, a method of assembly-induced charge transfer for changing the polarity of molecules was proposed to achieve highly selective Cu2+ detection. The colorimetric molecule Erie Garnet (EG) is assembled to the surface of single lay RGO (reduced graphene oxide) through simple molecular assembly. Theoretical calculations and experimental results show that through assembly-induced charge transfer, the polarity of the EG molecule is significantly altered, and the dipole moment increases from 3.579D to 29.552D. This change in polarity improves the chelating properties of EG, even in the presence of certain interfering ions (even trivalent Fe3+ and Al3+), it can selectively sense Cu2+ in complex environments with a detection limit as low as 0.98 μM. The recovery rate and relative standard deviation of Cu2+ are 97.75 % ∼ 100.8 % and ≤4.8 %, respectively. The mechanism of assembly, deaggregation effect, selective detection and optical stability were investigated in detail, respectively.

A Rare Natural Benzo[k,l]xanthene as a Turn-Off Fluorescent Sensor for Cu2+ Ion.

Rapid and efficient analyses of copper ions are crucial to providing key information for Cu2+ in living cells because of their biological importance. In this study, we reported one new turn-off fluorescent sensor for Cu2+ with a benzo[k,l]xanthene core, which served as an efficient cation sensor for copper ion over a wide range of other cations (Na+, K+, Ag+, Hg2+, Cd2+, Co2+, Ni2+, Zn2+, Mg2+, and Fe3+) owing to the catechol group in the aromatic core. The sensor showed selectivity for Cu2+ over other ions; the logKβ for Cu2+ binding to compound 1 had a value of 13.265. In the presence of Cu2+, sensor 1 provided significant fluorescence decrement; Co2+, and Ni2+ caused a fluorescence decrement when employed at a higher concentration than Cu2+, while Na+, K+, Hg2+, Cd2+, Zn2+, and Mg2+ metal ions produced only minor changes in fluorescence intensity. Fluorescence experiments demonstrate that compound 1 may have an application as a fluorescent probe for detecting Cu2+ with a limit of detection of 0.574 µM.

Cu2+ activated persulfate for sulfamethazine degradation

Sulfonamide antibiotics (SAs) are widely used in veterinary medicine but are poorly metabolized in biological systems; thus, they can cause a selective pressure to promote the proliferation of antibiotic resistant pathogens and threaten human health. Persulfate (PS)-based advanced oxidation processes (AOPs) have been applied for SA degradation, but using transition metal ions as PS activators is relatively limited. In this study, sulfamethazine (SMZ) was used as a model SA to evaluate the performance of a Cu2+ -activated PS system. Cu2+-PS exhibited better SMZ removal than other metal ions, and 25 mg/L SMZ can be degraded in the presence of 0.2 mM Cu2+ and 2.5 g L−1 PS within 120 min. Various anions inhibited SMZ degradation to different degrees except HCO3−. Among the cations, Fe3+ significantly inhibited SMZ removal, while Ni2+ increased the removal rate. High concentrations of humic acid and protein also increased the degradation rate of SMZ. Radical and singlet oxygen quenching experiments, together with the results of electron spin-resonance spectroscopy (ESR), showed that the main active species generated from Cu2+-PS are SO4·- and ·OH. The degradation pathway of SMZ was identified through HPLC-HRMS. Direct SO4·- and ·OH oxidation products of SMZ were not found, suggesting that the complex formed between Cu2+ and SMZ may affect the fate of SMZ. On the other hand, the efficiency and selectivity of Cu2+-PS against different SAs were confirmed. Overall, this study provides a facile and effective method for SMZ and other SA removal.

A novel anthrapyridone diamine-based probe for selective and distinctive Cu2+ and Hg2+ sensing in aqueous solution; utility as molecular logic gates

A newly synthesized anthrapyridone-based diamine (probe 1) having two metal ion binding sites exhibited selective and sensitive sensing of Cu2+ or Hg2+ among various metal ions. Upon addition of the metal ion, the probe 1-containing solution vividly changed color, enabling visual detection of each metal ion (Cu2+ or Hg2+) without requiring any instruments. A ratiometric approach insensitive to environmental interference provided limit of detections (LODs) of 1.0 and 2.0 μM for Cu2+ and Hg2+ sensing, respectively. The green fluorescence emission of probe 1 was entirely (Cu2+) or partially (Hg2+) quenched in the presence of the metal ion, yielding an observed fluorescence-based LOD (5/200 nM for Cu2+/Hg2+). Thus, probe 1 showed a dual responsiveness for detection of the metal ion. A model probe (2) with only a single metal binding site was ineffective at sensing the metal ion (Cu2+ or Hg2+) under the same conditions, demonstrating that the presence of the two binding sites in probe 1 is essential for the sensitive detection of the metal ion. The DFT calculations suggest binding of the metal ion to the probe with a stoichiometry of 1:1 or 2:1 (M2+: probe). Probe 1 was also effective at detecting a small amount of Cu2+ in live HeLa cells or real samples such as tap and lake waters. The UV–Vis. absorbance results of probe 1 with Cu2+ and Hg2+ enabled us to build ‘NOR-YES-INHIBIT’ molecular logic gates. The metal ion sensing system presented here was extensively investigated by various techniques including UV–visible, fluorescence, NMR spectroscopy, DFT calculations, FE-SEM, and DLS.

Synthesis of multidentate functional monomer for ion imprinting.

In this work, N,N,N-tri(2-carboxyethyl)-3-(2-aminoethylamino)propyl-trimethoxysilane was prepared as a multidentate functional monomer. The 3D model of the monomer coordinating with Cu2+ indicated that the monomer is able to provide five ligating atoms like ethylenediaminetetraacetic acid-Cu2+ to complex with Cu2+ . When Cu2+ was used as a template ion, the synthesis conditions of Cu2+ -imprinted polymers were optimized upon orthogonal design. It is interesting to find that Cu2+ -imprinted polymer offers a selectivity coefficient of 192.2 when the molar ratio of Cu2+ to monomer was exactly 1:1. That means there is no excess ligating atom in the ion-imprinted polymer and therefore, the nonspecific adsorption could be avoided. Benefiting from the excellent selectivity of Cu2+ -imprinted polymer, even if the concentration of Zn2+ was 25 times that of Cu2+ , Cu2+ -imprinted polymer still affords a high selectivity coefficient. Finally, the optimal synthesis conditions for Cu2+ -imprinted polymer, except the pH, were adopted to prepare Ni2+ -imprinted polymer, and Ni2+ -imprinted polymer also offered satisfying selectivity to Ni2+ . That implies this multidentate monomer is adaptable in ion imprinting and, the optimal synthesis conditions of Cu2+ -imprinted polymer except pH are likely suitable for the imprinting of other ions besides Cu2+ .

A novel electrochemical platform based on indenoindole for selective detection of Cu2+ ions in Punica granatum fruit juice

In this study, we have synthesized 5-ethyl-5,10-dihydroindeno[1,2-b]indole (INID) through cyclization reaction method and confirmed by proton nuclear magnetic resonance spectroscopy. Cyclic voltammetry showed that a glassy carbon electrode modified with the INID exhibited an excellent electrocatalytic activity towards the oxidation/reduction of Cu2+ in 0.1 M acetate buffer solution (pH = 4.4). The effects of pH and scan rate were measured to determine the optimum conditions at which the INID/GCE showed the highest sensitivity with a lower detection limit. The oxidation peak current for Cu2+ was proportional to its concentration under optimized conditions in the range of 10–180 μM with a limit of detection of 28 nM (1.81 μg.L−1). Moreover, the fabricated sensor exhibited an excellent selectively to Cu2+ over other interfering metal ions. In addition, the selectivity of Cu2+ ions over other related metal ions present in various environments (or interaction receptor) was further investigated by density functional theory. Furthermore, the INID/GCE sensor demonstrated excellent selectivity, good stability, and reproducibility. In real sample analysis, the determination of Cu2+ in pomegranate juice samples was studied by standard addition method with good recoveries.

Facile and highly effective synthesis of nitrogen-doped graphene quantum dots as a fluorescent sensing probe for Cu2+ detection

Nitrogen-doped graphene quantum dots (N-GQDs) with high blue fluorescence efficiency were synthesized by the hydrothermal method from p-Phenylenediamine and p-Coumaric acid. The N-GQDs possess several superiorities, most significantly in excellent solubility and superior photostability. Besides, the as-prepared N-GQDs exhibit a uniform size distribution with a diameter of about 3.8 ± 0.5 nm. After dispersing the N-GQDs in water, the formed aqueous solution still presents a stable and homogeneous phase even after 2 months at room temperature. The N-GQD dispersion was further utilized as sensing probes for the selective detection of copper ions (Cu2+), which is realized by the photoluminescence (PL) quenching of N-GQDs after adding Cu2+. The detection limit for Cu2+ was found to be 57 nM L−1, with superior selectivity in the presence of other commonly interfering metal ions. The presented results in this study provide a facile and high-efficiency method for synthesizing N-GQDs, with ultra-high detectivity and selectivity for Cu2+ detection, offering numerous opportunities for the development of biosensing, bioimaging, environment monitoring, and others.

Sodium sulfite leads to the formation of fluorescent organic nanoparticles: Regulation from aqueous solution, cellular pathway to security design patterns

Fluorescent organic nanoparticles (FONs) play important roles in the monitoring and controls of biological systems. To fulfill such duties, we have to investigate how the nanoplatforms interact with living matters. Currently, very limited information concerning the potential risks and toxicity has been reported for FONs except the MTT assay. In this contribution, the amine-rich cationic precursor (polyethyleneimine) initiates one-pot copolymerization with methyldopa sesquihydrate and water-soluble fluorescent nanoparticles are afforded. The influence of reduction agent (sodium sulfite) on the luminescence, microstructure and crystallinity has been discussed and the corresponding stabilities are substantially improved. Further studies reveal that selective Cu2+ detection has been realized due to “on-off” change and the limit of detection is determined to be 52 nM. It has been discovered that glutathione (GSH) can recover its green luminescence in terms of strong affinity of GSH to copper ions. For the first time, three different cell viability experiments including MTS assay, Annexin V-APC/7-AAD kit and double stain technique have been performed to support the negligible cytotoxicity of FONs in living cells. Spectra imaging has been employed for the identification of Cu2+ and GSH in HeLa cells. In addition, the Cu2+-GSH pairs can generate an “AND” logic gate during recognition sequence operations. It will be the first example that the effectiveness of encryption and decryption has been verified via Cu2+ and GSH based on FONs.

A Schiff-based fluorescence sensor for the detection of Cu2+ and its application in living cells

A novel fluorescent and colorimetric probe FL was designed and synthesized for selective Cu2+ detection in aqueous solutions. The detection limit of probe FL for Cu2+ was determined to be 1.09 μM. Furthermore, probe FL was successfully used to recognize Cu2+ in living cells, indicating its high potential in biological imaging applications.

Solvothermal synthesis of in situ nitrogen-doped Ti3C2 MXene fluorescent quantum dots for selective Cu2+ detection

Two-dimensional MXenes have attracted increasing attention from researchers in the optical, electrical and thermal fields due to their high electric conductivity, thermal conductivity and mechanical properties. MXene quantum dots (QDs) have been highly desired to achieve selective ion detection using highly fluorescent media. In this study, a facile route using amine-assisted solvothermal tailoring was developed to prepare in situ nitrogen-doped Ti3C2 MXene QDs. Pristine MXene was exfoliated to yield MXene with a few layers. Diethylenetriamine, few-layer MXene and N,N-dimethylformamide were blended to perform a solvothermal process, yielding in situ nitrogen-doped MXene QDs with an ~1 nm thickness and ~6.2 nm size. The formation of QDs was dynamically monitored. The reduction in the QD size depended on tailoring and in situ nitrogen doping. Fluorescence properties of those QDs were studied. Nitrogen-doped QDs exhibited different fluorescence-quenching responses to various metal cations. Selective Cu2+ detection using the nitrogen-doped QDs mainly depended on a static fluorescence-quenching mechanism. This study might provide opportunities for the large-scale fabrication of in situ element-doped MXene fluorescent QDs.

Computational Approach to Evaluate Eugenol Affinity and Derivatives Empirical Against Cu(II)

A computational approach to assess the emperical results of eugenol affinity, eugenoxy acetate (EOA), and pyridine methyl eugenoxy acetate (PMEOA) against Cu2+has been done. This research aims to determine the effects of the functional groups (−OH, −COOH, and −N) on eugenol and their derivatives on the selectivity of Cu2+adsorption experimentally and to calculate the energy interaction between eugenol compounds and derivatives with Cu2+. The experimental approach was carried out by solvent extraction method, using 10 mL of Cu2+10 ppm solution along with 0.3089 mmol of eugenol, EOA and PMEOA. The remaining concentration of Cu2+metal after extraction in the water phase was measured using an Atomic Absorption Spectrophotometer (AAS). Assessments of the Cu2+metal interaction with eugenol, EOA and PMEOA compounds were carried out using the ab initio method with 6-31G** basis set to predict the interaction energy. The results showed that pyridine methyl eugenoxy acetate (PMEOA) can separate Cu2+better than eugenol and EOA with extraction efficiency (% E) = 78.76%. The calculation results of Cu2+metal interactions with eugenol, EOA, and PMEOA compounds found that PMEOA has the lowest energy of interaction compared to eugenol and EOA with Cu2+metal.