Sensor For Cu2 Research Articles

Post-functionalization of Fluorinated Dibenzosulfone-based Conjugated Polymer for Smart 'Turn-off' Sensing of Cu2+ Ions.

Post-functionalization of conjugated polymeric backbone with various N-containing heterocycles through nucleophilic aromatic substitution reaction (SNAr) demonstrates crucial tailoring of their photophysical properties. This study explores an approach of post-polymerization modification of a fluorinated dibenzosulfone-based conjugated polymer aiming to incorporate functional groups having coordinating sites to bind metal ions. The resulting polymers, namely BDT-DBTS-IM, BDT-DBTS-TR, and BDT-DBTS-PY, revealed successful substitution reactions with imidazole, triazole, and pyridine respectively, andshowed significant changes in their absorption and emission properties. Notably, BDT-DBTS-IM demonstrated exceptional performance as a chemosensor, exhibiting a dramatic fluorescence turn-off response specifically to copper ions (Cu2+) with the limit of detection of 26 nM and Stern-Volmer quenching constant (KSV) of 8.2×105 Lmol-1. This high selectivity and sensitivity are attributed to the ability of the imidazole group to form a stable complex with Cu2+, resulting in both static and dynamic quenching efficiently. Our findings underscore the potential of post-polymerization modifications to significantly enhance the functionality of conjugated polymers. The ability of BDT-DBTS-IM to detect trace levels of copper ions with high precision highlights its practical utility in environmental and biological monitoring. This research not only demonstrates an approach for post-polymeric modification through SNAr reaction but also opens new avenues for developing sensors.

A novel fluorescent probe with high sensitivity and selectivity for “On-Off-On” sensors for Cu2+ cations and CN− anions

A novel fluorescent probe NIPF was synthesized by the Suzuki reaction to recognize Cu2+ and CN−. With the addition of Cu2+, NIPF exhibited strong fluorescence quenching (90 % for NIPF) with a Ksv value of 3.4 × 106 M−1 and a detection limit of 9.04 × 10−10 M. Subsequently, CN− was added to the NIPF-Cu2+ solution, and [Cu(CN)x]n− was formed due to the strong interaction between Cu2+ and CN− leading to fluorescence recovery (89 % for NIPF-Cu2+). In addition, a detection limit of 3.6 × 10−8 M was obtained by fluorescence titration. Meanwhile, it was demonstrated that the sensor achieved 93 %–105 % recovery of Cu2+ in the tested environmental samples, and the practicability of Cu2+ and CN− detection were verified using hydrogels test, with significant color changes observed under 365 nm light. Accordingly, the fluorescent probe NIPF was used to recognize Cu2+ and CN− by the “on-off-on” sensors.

Synthesis of Phenol-Hydrazide-Appended Tetraphenylethenes as Novel On-Off-On Cascade Sensors of Copper and Glutathione.

This study reports the synthesis of novel fluorescent probes, phenol-hydrazide-appended tetraphenylethenes (TPEs I and II), and explores their photochemical properties. The probes exhibit aggregation-induced emission (AIE) in increasing water content, as observed using fluorescence spectroscopy. Further investigation with UV-vis and fluorescence techniques revealed their potential as ion sensors. Both TPE I and TPE II act as "turn-off" sensors for Cu2+ ions, showing decreased fluorescence intensity in their presence. Their limit of detection (LOD) and association constant (K a) for Cu2+ were found to be comparable at 747 nM/597 nM, and 2.46 × 105 M-1/2/1.78 × 105 M-1/2, respectively. Moreover, the quantum yields of TPE I and TPE II were also calculated and found to be 0.651 and 0.325, respectively. Interestingly, these probes also function as "turn-on" sensors for glutathione (GSH) in the presence of copper. This means their fluorescence can be reversibly switched off and on by alternating CuCl2 and GSH additions. Moreover, the LOD values for GSH with TPE II-Cu2+ were calculated to be 544 nM. In addition, the investigation also employed visual analysis to assess the color alterations of TPEs on filter paper and in real water samples. Overall, this research introduces promising new probes with potential applications in copper ion detection and biomolecule glutathione sensing in real water samples.

Synthesis and characterization of a rhodamine derivative as a selective switch-on fluorescent sensor for Cu2+ ions in aqueous PBS buffer and living cells

A novel rhodamine-based receptor molecule (L1) was synthesized via the reaction between rhodamine hydrazide and acetylacetone.

A highly selective and sensitive electrochemical Cu(II) detector based on ion-imprinted magnetic carbon nanospheres

An electrochemical sensor for Cu(II) based on ion-imprinted polymers was prepared by combining surface imprinting with electrochemical polymerization deposition. The sensor was modified by ion-imprinted magnetic carbon nanospheres with a specific selectivity and sensitivity for Cu(II). The morphology and structure of the materials were characterized and analyzed. Sensors with the imprinted electrode had a stronger selectivity and higher sensitivity towards Cu(II) compared with their original counterparts. Within relative concentrations of Cu(II) from 10−6 to 10−10 mol L−1, the detection limit of the sensor was as low as 5.138×10−16 mol L−1 (S/N=3). The sensor is resistant to interference, and has good reproducibility, and stability, making it excellent for the electrochemical detection of metal ions.

Engineering of An Aptamer-Functionalized Fluorescent DNA Sensor for Cu(II) Responding in Living Tumor Cells.

Copper ions play vital roles in regulating life processes and being closely involved in several diseases such as cancer. Although detection methods based on fluorescent sensors or other strategies have been developed, it still remains a challenge to simultaneously realize the convenience, specificity, and accuracy in intracellular copper ion analysis. Herein, we propose an aptamer-functionalized DNA fluorescent sensor (AFDS) for accurate and specific detection of Cu(II) both in vitro and in cells by engineering the linkage of two DNA aptamers, namely, Lettuce aptamer and AS1411 aptamer, to achieve the manner of recognition response. Taking advantage of the functions of each aptamer, the tumor cell recognition capability and the high-contrast detection performance are simultaneously equipped in the AFDS. Furthermore, the AFDS shows high specificity and selectivity in Cu(II) response to avoid interference from common metal ions, chelators, and reactants by being associated with the irreversible interaction between nucleobases and Cu(II), which can destroy the topological structures and switch off the fluorescence of the AFDS. It also enables a sensitive in vitro detection of Cu(II) with a detection limit as lower as 0.1 μM and a wide detection linear range from 0.1 to 300 μM. The feasibility and superiority of the AFDS provide an opportunity to reveal both concentration-dependent and time-dependent intracellular Cu(II) responses in living cells. Therefore, the AFDS has achieved the novel detection performance of Cu(II) to exhibit great potential in exploring copper-related biological and pathological research.

Anthocyanin-induced color changes in bacterial cellulose nanofibers for the accurate and selective detection of Cu(II) in water samples

The environment and our health are negatively impacted by heavy metal ions, like Cu(II). The present study developed a green and effective metallochromic sensor that detects copper (Cu(II)) ions in solution and solid state using anthocyanin extract from black eggplant peels embedded in bacterial cellulose nanofibers (BCNF). Cu(II) is quantitatively detected by the sensing method with detection limits between 10-400 ppm and 20–300 ppm in solution and solid state, respectively. In the solution state, we depicted a sensor for Cu(II) ions in aqueous matrices in the pH range from 3.0 to 11.0, with the capability to produce a visual color change from brown to light blue and dark blue depending on the Cu(II) concentration. Additionally, BCNF-ANT film can act as a sensor for Cu(II) ions in the pH range of 4.0–8.0. Neutral pH was selected from the standpoint of high selectivity. It was found that visible color changed when Cu(II) concentration was increased. Bacterial cellulose nanofibers modified with anthocyanin were characterized with ATR-FTIR and FESEM. Various metal ions, including Pb2+, Co2+, Zn2+, Ni2+, Al3+, Ba2+, Hg2+, Mg2+, and Na+, were used to challenge the sensor to determine its selectivity. Anthocyanin solution and BCNF-ANT sheet were employed in the actual tap water sample successfully. The results also clarified that the various foreign ions did not significantly interfere with Cu(II) ions detection at optimum conditions. Compared to previously developed sensors, no electronic components, trained personnel, or sophisticated equipment were needed to apply the colorimetric sensor developed in this research. Cu(II) contamination in food matrices and water can be monitored on-site easily.

Efficient removal and sensing of copper(II) ions by alkaline earth metal-based metal–organic frameworks

A class of alkaline earth metal-based metal–organic frameworks (MOFs), namely NDCMOF(Ca) and NDCMOF(Sr), has been synthesized using 2,6-naphthalenedicarboxylic acid (NDC) as the linker. In view of the biocompatibility of the starting materials, these MOFs are expected to be environmentally benign and, in this work, have been employed for the removal of copper(II) ions (Cu2+) from aqueous systems. The results showed that the maximum adsorption capacities of NDCMOF(Ca) and NDCMOF(Sr) for Cu2+ were 299.4 and 398.4 ​mg ​g−1, respectively, which were comparable to those of related MOFs and porous materials. Meanwhile, NDCMOF(Ca) and NDCMOF(Sr) displayed blue luminescence in the solid state at room temperature upon photoexcitation with ultraviolet (UV) light. This emission would be readily quenched after the adsorption of Cu2+ ions. Such visible changes in the observed color and emission of the MOFs have rendered them versatile adsorbents and sensors for Cu2+ in the aqueous environment.

Development in Fluorescent OFF-ON Probes Based on Cu2+ Promoted Hydrolysis Reaction of the Picolinate Moiety.

Anions and cations have a key role in our normal life. Cu2+ ion is a crucial trace element accountable for the part of several cellular enzymes and proteins, including cytochrome c oxidase, dopamine monooxygenase, Cu/Zn superoxide dismutase, and ceruloplasmin. WHO has found the extreme acceptable level of Cu2+ ions in drinking water is up to 2.0ppm. Excess use of Cu2+ ions is associated with various human genetic disorders. Thus, the visualization of Cu2+ ions to avoid its toxic effects in chemical and biological systems is significant. In this review we have summarized sensors based on catalytic hydrolysis of picolinate to detect Cu2+ ions. The sensors based on hydrolysis of picolinate are very selective as compared to the other sensors for Cu2+ ions detection. We have focused on describing the structure, spectral properties, detection limits, and bioimaging model of the sensors.

Optical and quantitative sensing capability of phenolphthalein derived Schiff base chromo‐fluorogenic sensor for Cu2+

Accurate tracking of Cu2+ is of major significance for several fields from human health to the environment and industry. Hence, well-organized, sensitive, and accurate methods for Cu2+ recognition in solutions are in special request. Herein, a novel phenolphthalein-based fluorogenic probe has been constructed by integrating a phenolphthalein-based building block with an amine-containing molecule. The probe was explored as a“switch-off” fluorogenicsensorfor Cu2+signaling in the presence of interfering cations in ionic concentrations and also displayed perfect selectivity/sensitivity toward Cu2+and faster equilibrium response time than any other reportedfluorogenic probes. As a sensing platform, the probe has a moderately experimental LOD of 84.0 nM Cu2+ in HEPES:CH3CN (v:v, 1:1, pH = 7). Binding affinity tests, MALDI–TOF MS techniques and theoretically DFT computations demonstrated that Cu2+formed coordinate bonds with phenolic hydroxyl and –CH = N groups of FPAB. The probe was successfully utilized for Cu2+ sensing in theFPABcoated silica plates and cotton swabs. The present study offers a fast, visible, low-cost and precise process for Cu2+ sensing.

Erdosteine-based potentiometric sensor for real-time surveillance of copper traces in food supplements and shredded canned tuna

Industrial anthropogenic activities pollute water and contaminate fish with heavy metals. The study presented a chemically modified carbon paste sensor for Cu (II) ion assay based on Cu-erdosteine association complex. The electrode exhibited a Nernstian response (29.6 ± 0.018 mV/decade) with a wide linear concentration range (1.99 ×10−6 −1 ×10−2 mol L−1). Over the pH range of 4.0–6.0, the potentiometric response of the fabricated electrode is independent of pH. The sensor determined the Cu (II) content in drug substances, pharmaceutical formulations, and tuna meat via potentiometric titration with EDTA. The method did not differ statistically from the method described in the literature.

Ultrasensitive detection of Cu2+: A cyanobiphenyl–based colorimetric and fluorescence chemosensor and its Smartphone and food sample applications

A new cyanobiphenyl–based compound 4–hydroxy–3–(((4–(phenylamino)phenyl)imino)methyl)–[1,1–biphenyl]–4–carbonitrile (PEBP) for Cu2+ detection was fabricated and successfully characterized. PEBP was employed as a sensor for Cu2+ sensing and used as an extremely fast responsive colorimetric and ''ON/OFF'' fluorescent sensor in H2O:CH3CN (40:60, v/v). Highly selective fluorescence response of PEBP to Cu2+ yielded an excellently low detection limit of 20.4 nM. Binding stoichiometry for PEBP−Cu2+ was found to be 2:1 by Job's plot study, as well MALDI TOF–MS data, and the binding constant was computed as 0.62 × 102 M−1/2. The validation study was employed using analytical parameters and statistical tests. To understand the binding capability, density functional theory (DFT) study was performed. Smartphone and applications for different food and drinking water samples were successfully constructed for Cu2+ detection, and the findings revealed that PEBP could be easily employed for in–site Cu2+detection without sophisticated instrument.

Click Chemistry ‐ Inspired Synthesis of Porphyrin Hybrid Glycodendrimers as Fluorescent Sensor for Cu(II) Ions

AbstractAn expeditious and modular CuAAC ‘click’ protocol has been exploited for the construction of porphyrin cored hybrid glycodendrimers of G1 and G2 generation. The developed porphyrin hybrid glycodendrimers were characterized using extensive spectral analysis including NMR (1H, 13C, and 19F), MS, MALDI‐TOF, IR, and SEC datas and evaluated for their sensing ability for a range of metal ions, where they displayed notable sensing for Cu(II) ion with solvatochromism properties.

Application of 2,4,5-tris(2-pyridyl)imidazole as 'turn-off' fluorescence sensor for Cu(II) and Hg(II) ions and in vitro cell imaging.

The 2,4,5-tris(2-pyridyl)imidazole (L) molecule has been evaluated as a probe for dual sensing of Hg2+ and Cu2+ ions in EtOH/HEPES buffer medium (5 mM, pH = 7.34, 1:1, v/v). Probe L shows a good sensitive and selective turn-off response in the presence of both Hg2+ and Cu2+ ions, which is comprehensible under long UV light. The probe can detect Cu2+ ion in the pH range 3-11 and Hg2+ ion in pH 6-8. The limit of detection for Cu2+ (0.77 μM) is well under the allowable limit prescribed by the United States Environmental Protection Agency. Two metal (Cu2+ /Hg2+ ) ions are needed per L for complete fluorescence quenching. The probe shows marked reversibility on treatment with Na2 EDTA, making the protocol more economical for practical purposes. Paper strip coated with the L solution of EtOH can detect the presence of Cu2+ and Hg2+ ions in the sample using visible quenching of the fluorescence intensity. Density functional theory-time-dependent density functional theory (DFT-TDDFT) calculations support experimental observations, and d-orbitals of Cu2+ /Hg2+ provide a nonradiative decay pathway. Cell imaging study using HDF and MDA-MB-231 cells also supported the viability of L in detecting Cu2+ and Hg2+ ions in living cells.

A highly selective fluorescent sensor for Cu2+ based on naphthalimide containing aza‐crown ether

AbstractThe development of a fluorogenic chemosensors with high sensitivity for copper ion (Cu2+) has been receiving great attention in recent years because of their potential application in clinical biochemistry and the environment studies. In the present study, we designed and synthesized a fluorescent probe, Np‐azaCE, with 1,8‐naphthalimides as a core structure and 1,4‐diaza‐9‐crown‐3‐ether as a copper ion tweeze, which showed selective and sensitive fluorometric change upon addition of a copper ion. The Np‐azaCE chemosensor was highly selective for Cu2+ over the other metal ions with fluorescent quenching. Finally, the Cu2+ detection limit and job's plot of Np‐azaCE were calculated using UV–visible spectrophotometer and fluorescence spectrophotometer.

Carbazole‐based dual‐functional chemosensor: Colorimetric sensor for Co2+ and fluorescent sensor for Cu2+ and its application

AbstractA new carbazole derivative CNS was prepared by the condensation of 2‐hydrazine benzothiazole with 3‐aldehyde‐6‐naphthalene‐N‐butyl carbazole, which could highly selectively discriminate Co2+ and Cu2+ in different solvent systems. CNS could enable the recognition of Co2+ by the “naked eye,” with the color changing from colorless to pale yellow in DMSO/H2O (v/v = 1:1). The addition of Cu2+ made the fluorescence emission intensity increase nearly 10 times, which was accompanied by a weak blue shift of the emission peak in CH3CN. Under the illumination of 365 nm ultraviolet lamp, the color of the CNS solution changed from light blue to dark blue after Cu2+ was added. The binding process could be reasonably speculated by spectrometric titrations, 1H NMR, mass spectrometry (MS) analysis, and density functional theory (DFT) calculation. The results of fluorescence electron microscopy showed that CNS could be used as a fluorescent sensor to detect Cu2+ in Hela cells. In addition, CNS was successfully used for the detection of Cu2+ in actual water samples.

A novel multi-stimuli-responsive organogel sensor for detecting Cu2+ and Co2+ based on benzotriazole derivative

A novel low molecular organic gelator (BTA) based on the derivative of benzotriazole has been successfully synthesized and developed. Extremely stable organogel (BTAG) with the low critical gelation concentration could be formed in methanol by heating and cooling. Interestingly, the BTAG could act as a multi-stimuli-responsive sensor for detecting Cu2+ and Co2+ and presents selective fluorescent and colorimetric response for Cu2+ and Co2+. Moreover, the detection limits of the multi-stimuli-responsive sensor for Cu2+ and Co2+ ions are 0.962 × 10−6 M and 1.08 × 10−6 M, respectively. Notably, the BTAG could be induced to a rare organo-to-metallogel transformation at room temperature by Cu2+ or Co2+ without any external assistances. The results provide an effective strategy for sensing Cu2+ and Co2+ and also offer a new method for the enrichment of Cu2+ and Co2+ in the environment with the low molecular organogel.

Glycerol‐Triazole Conjugated Rhodamine as Colorimetric and Fluorimetric Sensor for Cu2+

AbstractA glycerol‐triazole tethered rhodamine based colorimetric and fluorimetric sensor 3′,6′‐bis(diethylamino)‐2‐(((1‐(1,3‐dihydroxypropan‐2‐yl)‐1H‐1,2,3‐triazol‐4‐yl)methylene)aminospiro [isoindoline‐1,9′‐xanthen]‐3‐one (L1) is designed and synthesized for the selective recognition of Cu2+ ion. The sensor L1 allows naked eye detection of Cu2+ ion with a fast response (<1 min). Among the various metal ions tested, the sensor L1 shows selective binding with Cu2+ through turn‐on fluorescence mechanism. The sensor shows 1 : 2 binding stoichiometry with binding constant, Ka=1.1×106 M−2 as revealed by job's plot & Benesi‐Hildebrand plot (B−H plot), respectively. The detection limit of L1 with Cu2+ ion is found to be 3.3 μM. Further, the experimental results are also validated using density functional theoretical (DFT) study. The optimized geometries indicates that the formation of the L1‐Cu2+ complex is thermodynamically favourable by ΔG=−11.7 kcal/mol. The HOMO‐LUMO gap of the ligand L1 is found to be 3.49 eV, which decreases to 1.76 eV upon complexation with copper.

Four Novel d10 Metal-Organic Frameworks Incorporating Amino-Functionalized Carboxylate Ligands: Synthesis, Structures, and Fluorescence Properties.

By employment of amino-functionalized dicarboxylate ligands to react with d10 metal ions, four novel metal-organic frameworks (MOFs) were obtained with the formula of {[Cd(BCPAB)(μ 2-H2O)]}n (1), {[Cd(BDAB)]∙2H2O∙DMF}n (2), {[Zn(BDAB)(BPD)0.5(H2O)]∙2H2O}n (3) and {[Zn(BDAB)(DBPB)0.5(H2O)]∙2H2O}n (4) (H2BCPAB = 2,5-bis(p-carbonylphenyl)-1-aminobenzene; H2BDAB = 1,2-diamino-3,6-bis(4-carboxyphenyl)benzene); BPD = (4,4′-bipyridine); DBPB = (E,E-2,5-dimethoxy-1,4-bis-[2-pyridin-vinyl]-benzene; DMF = N,N-dimethylformamide). Complex 1 is a three-dimensional (3D) framework bearing seh-3,5-Pbca nets with point symbol of {4.62}{4.67.82}. Complex 2 exhibits a 4,4-connected new topology that has never been reported before with point symbol of {42.84}. Complex 3 and 4 are quite similar in structure and both have 3D supramolecular frameworks formed by 6-fold and 8-fold interpenetrated 2D coordination layers. The structures of these complexes were characterized by single crystal X-ray diffraction (SC-XRD), thermal gravimetric analysis (TGA) and powder X-ray diffraction (PXRD) measurements. In addition, the fluorescence properties and the sensing capability of 2–4 were investigated as well and the results indicated that complex 2 could function as sensor for Cu2+ and complex 3 could detect Cu2+ and Ag+ via quenching effect.

Tetraphenylpyrazine-Based Manganese Metal-Organic Framework as a Multifunctional Sensor for Cu2+, Cr3+, MnO4-, and 2,4,6-Trinitrophenol and the Construction of a Molecular Logical Gate.

A tetraimidazole-decorating tetraphenylpyrazine has been designed and utilized for the fabrication of a novel metal-organic framework (MOF), denoted as {Mn(Tipp)(A)2}n·2H2O (TippMn, where Tipp = 2,3,5,6-tetrakis[4-[(1H-imidazol-1-yl)methyl]phenyl]pyrazine and A = deprotonation of 1,4-naphthalenedicarboxylic acid), through hydrothermal synthesis. Structural analysis reveals that TippMn possesses a 2-fold-interpenetrated 4,8-connected three-dimensional (3D) network with an unprecedented {416·612}{44·62} topology. Fluorescent spectral investigations indicate that TippMn shows discriminative fluorescence when treated by Cr3+ and Cu2+, giving an INHIBIT logical gate performance. Meanwhile, TippMn can be further used as a sensor for MnO4- and 2,4,6-trinitrophenol (TNP) by fluorescence quenching. Notably, the sensing processes toward Cu2+, Cr3+, MnO4-, and TNP are labeled with high selectivity and sensitivity, quick response, and good recyclability. It is anticipated that this MOF-based versatile sensor could shed light on the exploration of MOFs for fluorescent sensors, optical switches, etc.