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Q-graphene-scaffolded covalent organic frameworks as fluorescent probes and sorbents for the fluorimetry and removal of copper ions
摘要： Metal-free fluorescent covalent organic frameworks (COFs) were synthesized initially with Q-Graphene (QG) scaffolds by the one-step covalent reactions of melamine-aldehyde and phenol-aldehyde poly-condensations using paraformaldehyde. It was discovered that onion-like hollow QG, which consists of multi-layer graphene and different carbon allotropes having a high proportion of folded edges and surface defects, could endow the scaffolded COFs with enhanced green fluorescence and environmental stability. Unexpectedly, they could exhibit the powerful absorption for Cu2+ ions resulting in the specific quenching of fluorescence. A fluorimetric strategy with QG-scaffolded COFs was thereby developed to probe Cu2+ ions separately in blood and wastewater with the linear concentration ranges of 0.0010 - 10.0 μM (limit of detection of 0.50 nM) and 0.0032 - 32.0 μM (limit of detection of 2.4 nM), respectively, promising the potential applications for the field-applicable monitoring of Cu2+ ions in the clinical and environmental analysis fields. In addition, the prepared COFs sorbents were employed to absorb Cu2+ ions in wastewater showing high removal efficiency. More importantly, such an one-pot fabrication route with hollow QG scaffolds may be tailorable extensively for the preparation of a variety of metal-free multifunctional COFs with enhanced fluorescence, water solubility, environmental stability, and metal removal capability.
关键词： Q-Graphene Scaffold；Covalent Organic Frameworks；Fluorescent Analysis；Removal Sorbents；Copper Ions
更新于2025-09-23 15:23:52
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Reusable surface plasmon resonance sensor for rapid detection of Cu2+ based on modified-chitosan thin film as an active layer
摘要： In this article, a reusable surface plasmon resonance (SPR) sensor for rapid detection of copper ions (Cu2+), based on optimized silver/gold (Ag/Au) composite film modified by modified-chitosan (MCS) thin film as an active layer, was achieved. We employed a four-layer Kretchmann semi-cylindrical prism configuration and induced a reference beam into the experimental system to improve the sensitivity and stability, and investigated the cross-linking technique of CS solution, the spin coating process of MCS film, the stability of active layer, the rebirth power of SPR sensor, and the detection for trace Cu2+. The rate of swelling or dissolution of MCS film after flushing sensor chip for four times is less than 9×10?4/min, and the decline of signal value is less than 1.5% after MCS film adsorbing Cu2+ and multiple flushing. The elution and capacity rates are above 96% after five times of elution for the sensor by EDTA solution with 0.5mmol/L. Within 1-5ppm, the SPR sensor was found to possess sensitivity of 0.7271ppm?1. The LOD is 18ppb for the trace Cu2+. The present SPR sensor not only could be used in trace monitoring of Cu2+ but also could be extended to other potential applications.
关键词： Copper ions,Reutilization,Composite film,Modified-chitosan,Surface plasmon resonance
更新于2025-09-23 15:23:52
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Colorimetric detection of copper ions using gold nanorods in aquatic environment
摘要： On the basis of that Cu2+ can accelerate the leaching rate of Au by thiosulfate, a colorimetric, unlabeled and non-aggregating gold nanorod (GNR) probe has been developed for the determination of trace-level Cu2+ in aqueous solutions. Our study demonstrates a high sensitivity and rapid response towards Cu2+ with a detectable range (20–200 nM). E?ect factors such as the ratio of NH3/NH4Cl, the concentration of S2O3 2?, the bath temperature and the heating time were researched to investigate the in?uences on the copper detection process by GNRs sensor. The method studied in this project is highlighted by its high selectivity and high tolerance to interferences, which can be used to detect trace amounts of Cu2+ ions in water samples quickly and sensitively, indicating the potential suitability of copper detection in various applications.
关键词： Gold nanorods,Copper ions,Catalytic leaching,Colorimetric detection
更新于2025-09-23 15:22:29
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Rapid Quantitative Fluorescence Detection of Copper Ions with Disposable Microcapsule Arrays Utilizing Functional Nucleic Acid Strategy
摘要： In this work, an economical and easy-to-use microcapsule array fabricated by ice printing technique has been realized for ultrasensitive fluorescence quantification of copper ions employing functional nucleic acid strategy. With ice printing, the detection reagents are sealed by polystyrene (PS) film isolation and photopolymer, which guarantees a stable and contamination-free environment for functional nucleic acid reaction. Our microcapsule arrays have shown long-term stability (20 days) under ?20 °C storage in frozen form before use. During the Cu2+ on-site detection, 1 μL sample is simply injected into the thawy microcapsule by a microliter syringe under room temperature, and after 20 minutes the fluorescence result can be obtained by an LED transilluminator. This method can realize the detection limit to 100 nM (100 fmol/μL) with high specificity.
关键词： ice printing,functional nucleic acid,fluorescence detection,copper ions,microcapsule arrays
更新于2025-09-19 17:15:36
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A large Stokes shift, sequential, colorimetric fluorescent probe for sensing Cu2+/S2- and its applications
摘要： Copper ions (Cu2+) and sulfide (S2?) are important markers in many physiologies and pathological processes. In this work, a new near-infrared fluorescent probe 1 for colorimetric and sequential detection of Cu2+/S2? was designed and developed. The probe showed a rapid (less than 1 min), highly selective and sensitive response toward copper ions. Notably, the probe could also be applied to detect S2? through reversible formation-separation of complex 1-Cu2+ and CuS with a large Stokes shift of 234 nm. The detection limit for Cu2+ and S2? was found to be 1.8 × 10-8 M and 1.5 × 10-8 M, respectively. Furthermore, the binding stoichiometry between 1 and Cu2+ was found to be 1:1, the binding mode was also demonstrated using density functional theory (DFT) calculations and contrastive compound research. In addition, the probe was successfully applied in real water samples assay for the detection of Cu2+, and the strip papers experiments also showed that probe 1 can be used to detect Cu2+ and S2?.
关键词： DFT calculations,Colorimetric,Near-infrared,Sulfide,Large Stokes shift,Copper ions
更新于2025-09-19 17:15:36
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Cu2+-mediated Fluorescence Switching of Graphene Quantum Dots for Highly Selective Detection of Glutathione
摘要： As a short peptide containing active thiol group, glutathione (GSH) participates in many cellular reactions, so it is of great significance to detect cellular GSH. In this work, amino-rich graphene quantum dots (GQDs) were synthesized, which could coordinate with copper ions (Cu2+) and yield aggregation-induced fluorescence quenching. However, GSH owns stronger coordination ability with Cu2+, so that GSH could promote the dissociation of Cu2+ from the surface of GQDs, and then led to the fluorescence recovery of GQDs. In BR buffer medium at pH 6.8, GSH was able to gradually recover the fluorescence of GQDs (1 μg/mL) that was quenched by Cu2+ (250 μmol/L), which could be finished within 20 min. Additionally, the recovery degree of fluorescence was linear to the concentration of GSH in the range of 20─500 μmol/L with a detection limit of 3.4 μmol/L. This method was applicable to the detection of GSH in cell lysate by the switchable function of Cu2+ to improve the selectivity.
关键词： Graphene quantum dots,Fluorescence switching,Copper ions,Glutathione
更新于2025-09-19 17:13:59
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Investigation of photo-induced electron transfer between amino-functionalized graphene quantum dots and selenium nanoparticle and it's application for sensitive fluorescent detection of copper ions
摘要： Copper ions play an essential role in some biological processes. Currently, there is a need for the development of convenient and reliable analytical methods for the Cu2+ measurement. In the present work, a sensitive fluorescence method was developed for the determination of copper ions. Amino-functionalized graphene quantum dots (af-GQDs) and selenium nanoparticles (Se NPs) were synthetized, respectively, and they were characterized via transmission electron microscope, infrared spectrum analysis and X-ray photoelectron spectrum measurement. Photo-induced electron transfer (PET) between the prepared two nanomaterials could effectively quench the fluorescence of af-GQDs. Cu(II) was reduced to Cu(I) in the presence ascorbic acid and Cu2Se was finally generated on Se NPs surface, which led to the declined PET efficiency and inhibited the fluorescence quenching of af-GQDs. The change in fluorescence intensity was linearly correlated to the logarithm of the Cu2+ concentration from 1 nM to 10 μM, with a detection limit of 0.4 nM under the optimal conditions. The detections of copper ions in water samples were realized via standard addition method and the recovery values varied from 98.7% to 103%. The proposed fluorescence method was also employed to analyze the uptake of Cu2+ into human cervical carcinoma HeLa cells and cisplatin-resistant HeLa cells (HeLa/DDP cells). The experimental results indicate that the decreased hCTR1 expression level in HeLa/DDP cells weakened the uptake of copper ions into these drug-resistant tumor cells.
关键词： photo-induced electron transfer,selenium nanoparticles,cellular uptake,copper ions,fluorescence quenching,amino-functionalized graphene quantum dots
更新于2025-09-11 14:15:04
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Rapid immunological detection of copper ions using fluorescence immunochromatographic assay
摘要： One-step fluorescence immunochromatographic assay (FICA) has been developed using fluorescent microspheres-labelled monoclonal antibody (McAb) probe for the rapid detection of copper ions in herbal plants and soil samples were investigated in this study. The results can be read by the fluorescence reader according to the fitted standard curve equation. Under optimal conditions, detecting copper ions with FICA can be done within 15 min with a LOD (limit of detection) of 0.2 μg/L, and was very useful for the rapid onsite testing. A total of 31 solid samples were pre-treated by microwave digestion combined with cation exchange solid phase extraction and prepared as test samples for FICA and ICP-AES. The two methods showed good relativity with correlation coefficients of 0.924 and 0.969 in herbal plants and soil samples for copper detection, respectively. We hope that our research can help promote the daily monitoring of heavy metal pollution effectively.
关键词： Copper ions,fluorescence immunochromatographic assay,monoclonal antibody,rapid onsite testing
更新于2025-09-09 09:28:46