Copper nanoclusters (CuNCs) are attractive electrochemiluminescence (ECL) emitters as Cu is comparatively inexpensive, nontoxic, and highly abundant. However, their ECL yield is relatively low. Herein, we report that orderly self-assembly of CuNCs using DNA nanoribbon as the template (DNR/CuNCs) conferred the CuNCs with improved ECL properties compared with individual CuNCs in both annihilation and co-reactant processes. The DNR/CuNCs resulted in a high ECL yield of 46.8 % in K2S2O8, which was ≈68 times higher than that of individual CuNCs. This strategy was successfully extended to other ECL emitters, such as gold nanoclusters and the Ru(bpy)32+/TPrA system. Furthermore, as an application of DNR/CuNCs, a DNR/CuNC-based ECL biosensor with higher sensitivity was constructed for dopamine determination (two orders of magnitude lower than that previously reported), showing that DNR/CuNCs have a potential for application in ECL bioanalysis as a new type of superior luminophore candidate. 相似文献
Copper nanoclusters (CuNCs) are emerging electrochemiluminescence (ECL) emitters with unique molecule-like electronic structures, high abundance, and low cost. However, the synthesis of CuNCs with high ECL efficiency and stability in a scalable manner remains challenging. Here, we report a facile gram-scale approach for preparing self-assembled CuNCs (CuNCsAssy) induced by ligands with exceptionally boosted anodic ECL and stability. Compared to the disordered aggregates that are inactive in ECL, the CuNCsAssy shows a record anodic ECL efficiency for CuNCs (10 %, wavelength-corrected, relative to Ru(bpy)3Cl2/tripropylamine). Mechanism studies revealed the unusual dual functions of ligands in simultaneously facilitating electrochemical excitation and radiative transition. Moreover, the assembly addressed the limitation of poor stability of conventional CuNCs. As a proof of concept, an ECL biosensor for alkaline phosphatase detection was successfully constructed with an ultralow limit of detection of 8.1×10−6 U/L. 相似文献
Fluorescent copper nanoclusters (CuNCs) have been widely used in chemical sensors, biological imaging, and light-emitting devices. However, individual fluorescent CuNCs have limitations in their capabilities arising from poor photostability and weak emission intensities. As one kind of aggregation-induced emission luminogen (AIEgen), the formation of aggregates with high compactness and good order can efficiently improve the emission intensity, stability, and tunability of CuNCs. Here, DNA nanoribbons, containing multiple specific binding sites, serve as a template for in situ synthesis and assembly of ultrasmall CuNCs (0.6 nm). These CuNC self-assemblies exhibit enhanced luminescence and excellent fluorescence stability because of tight and ordered arrangement through DNA nanoribbons templating. Furthermore, the stable and bright CuNC assemblies are demonstrated in the high-sensitivity detection and intracellular fluorescence imaging of biothiols. 相似文献
Fluorescent copper nanoclusters (CuNCs) have been widely used in chemical sensors, biological imaging, and light‐emitting devices. However, individual fluorescent CuNCs have limitations in their capabilities arising from poor photostability and weak emission intensities. As one kind of aggregation‐induced emission luminogen (AIEgen), the formation of aggregates with high compactness and good order can efficiently improve the emission intensity, stability, and tunability of CuNCs. Here, DNA nanoribbons, containing multiple specific binding sites, serve as a template for in situ synthesis and assembly of ultrasmall CuNCs (0.6 nm). These CuNC self‐assemblies exhibit enhanced luminescence and excellent fluorescence stability because of tight and ordered arrangement through DNA nanoribbons templating. Furthermore, the stable and bright CuNC assemblies are demonstrated in the high‐sensitivity detection and intracellular fluorescence imaging of biothiols. 相似文献
Copper nanoclusters (CuNCs) as a new class of fluorescent materials have attracted a great deal of interest due to their outstanding fluorescence properties. In this work, a variety of organic solvents were used to induce self-assembly of glutathione-capped CuNCs (GSH-CuNCs) to form ordered assemblies with enhanced fluorescence properties. Assemblies with multicolor fluorescence emission were constructed on the basis of the aggregation-induced emission (AIE) of GSH-CuNCs and the solvent effect. The fluorescence emission from these GSH-CuNCs assemblies can also be tuned from yellow to purple by changing the organic solvent. A possible mechanism based on the size of the assemblies and electron transfer was explored to explain the solvent effects on GSH-CuNCs. Stimuli-responsive nanoswitches with excellent reversibility can be controlled by changing the type of organic solvent and the ratio of the organic solvent to the aqueous solution of GSH-CuNCs. As the CuNCs assemblies exhibit strong, stable, and color-tunable fluorescence, they were employed as color-conversion materials for recognizing different organic solvents. 相似文献
In general, copper nanoclusters (CuNCs) possess very low or even virtually no bactericidal effect. Herein,we report a novel CuNCs possessing significantly high antibacterial activity, that is tannic acid (TA)capped CuNCs (TA-CuNCs). TA-CuNCs exhibit strong absorption and excitation-dependent fluorescence within pH 2-12, resulting from the functional groups of TA-CuNCs due to two prototropic equilibria,phenolphenolate and carboxyliccarboxylate. There exists synergistic effect of TA and copper nanoclusters which endows TA-CuNCs remarkable antibacterial capability as a microbicide, as characterized by the effective inhibition on the growth of gram-positive bacteria by damaging the cell membrane. By incubating 1 x 10~7 CFU/mL of gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with 30 μg/mL of TA-CuNCs for 10 min, the bacteria are completely inhibited, while under same conditions the viabilities of gram-negative bacteria Escherichia coli 0157:H7 and Pseudomonas aeruginosa remain 85.0%, 72.0%, respectively. In addition, TA-CuNCs exhibit low cytotoxicity and favorable biocompatibility demonstrated by standard methyl thiazolyl tetrazolium (MTT) assay with HepG2 and 293 Tcells, giving rise to cell viability of 94.2% for HepG2 and 96.7% for 293 T by incubating 10~6 cell/mL with 200 μg/mL of TA-CuNCs for 24 h. These results make TA-CuNCs a potential alternative as bactericide for infection treatment caused by gram-positive bacteria. 相似文献
The authors describe a fluorometric glucose assay that is based on the use of MnO2 nanosheets and copper nanoclusters (CuNCs) acting as nanoprobes. The CuNCs were synthesized by using bovine serum albumin as a template by chemical reduction of copper(II) sulfate. On addition of MnO2 nanosheets to a colloidal solution of CuNCs, the fluorescence of CuNCs (measured at excitation/emission wavelengths of 335/410 nm) is quenched. However, in the presence of enzymatically generated H2O2, the MnO2 nanosheets are reduced to form Mn(II) ions. As a result, fluorescence intensity recovers. The glucose assay is based on the enzymatic conversion of glucose by glucose oxidase to generate H2O2 and glucuronic acid. The calibration plot is linear in the 1 μM to 200 μM glucose concentration range, and the detection limit is 100 nM. The method was successfully applied to the determination of glucose in spiked human serum samples.
Graphical abstract A sensitive fluorescent bioassay is reported for the detection of glucose based on the hydrogen peroxide-induced decomposition of a quencher system composed of MnO2 nanosheets and copper nanoclusters (CuNCs).
Stable copper nanoclusters (CuNCs) were prepared by utilizing D-penicillamine as both the stabilizer and reductant. The emission of the CuNCs (with excitation/emission peaks at 390/645 nm) is largely stabilized by coating with poly(sodium-p-styrenesulfonate) (PSS). Cytochrome c (Cyt c) quenches the fluorescence of the PSS-coated CuNCs, and this effect was exploited to design a quenchometric fluorometric assay for Cyt c. If trypsin is added to the loaded CuNCs, it will hydrolyze Cyt c to form peptide fragments, and fluorescence is gradually restored. A highly sensitive and fluorometric turn-off-on assay was constructed for sequential detection of Cyt c and trypsin. The linear ranges for Cyt c and trypsin are from 8.0 nM to 680 nM, and from 0.1 to 6.0 μg mL?1, and the lower detection limits are 0.83 nM and 20 ng mL?1 for Cyt c and trypsin, respectively.
Graphical abstract Schematic illustration of the fluorometric assay for trypsin based on the electron transfer between poly(p-styrenesulfonate)-protected copper nanoclusters (PSS-CuNCs) and cytochrome c (Cyt c).
Herein, an innovative and simple strategy for synthesizing high fluorescent Cu nanoclusters was successfully established while l-cysteine played a role as the stabilizer. Meaningfully, the current Cu nanoclusters together with a quantum yield of 14.3% were prepared in aqueous solution, indicating their extensive applications. Subsequently, the possible fluorescence mechanism was elucidated by fluorescence, UV–vis, HR-TEM, FTIR, XPS, and MS. Additionally, the CuNCs were employed for assaying Hg2+ on the basis of the interactions between Hg2+ and l-cysteine; thus facilitating the quenching of their fluorescence. The proposed analytical strategy permitted detections of Hg2+ in a linear range of 1.0 × 10−7 mol L−1 × 10−3 mol L−1, with a detection limit of 2.4 × 10−8 mol L−1 at a signal-to-noise ratio of 3. Significantly, this CuNCs described here were further applied for coding and fluorescent staining, suggesting may broaden avenues toward diverse applications. 相似文献
An electrochemical sensor based on modification of carbon paste electrode by glutathione‐capped copper nanoclusters silica nanoparticles (CuNCs/SiO2NPs) composite for determination of dopamine in the presence of ascorbic acid was presented. Transmission electron microscopy, scanning electron microscopy, energy dispersive X‐Ray analysis, X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction and electrochemical impedance spectroscopy were used for characterization of the developed electrode. The electrochemical behavior of dopamine on CuNCs/SiO2NPs/carbon paste electrode was investigated by cyclic voltammetry and differential pulse voltammetry. Dopamine was determined in the range of 10.0 – 900.0 μM, and the limit of detection was obtained as 0.43 μM. The electrochemical behaviors of the coexisting electroactive species, which often cause interference with the determination of dopamine, were investigated. The results show that the developed electrode does not show any interference with respect to coexisting species, even in the presence of ascorbic acid. The developed electrochemical sensor was further employed for the determination of dopamine in human blood plasma, with a good recovery. 相似文献
The authors report on a simple strategy for sensitive determination of the activity of terminal deoxynucleotidyl transferase (TdT) using copper nanoclusters (CuNCs) as fluorescent probes. TdT-polymerized long chain AT-rich DNA serves as a template for the synthesis of the CuNCs, and TdT activity is detected fluorometrically at excitation/emission wavelengths of 340/570 nm. The protocol relies on the target-triggered formation of dsDNA polymers and in-situ formation of CuNCs. The calibration plot is linear in the 0.7 to 14 U L?1 activity range, with a 60 mU L?1 detection limit (at a signal-to-noise ratio of 3). The protocol was applied to determine TdT activity in acute lymphatic leukemia cells. This approach is selective, simple, convenient and cost-efficient because a complex DNA sequence is not required. In our perception, the method provides a viable new platform for monitoring the activity and inhibition of TdT.
Graphical abstract Based on the target-triggered formation of dsDNA polymers and in-situ formation of CuNCs with strong fluorescence, a turn-on fluorescence assay for TdT activity is presented.
The authors report that sulfide ions are capable of inhibiting the peroxidase-like activity of copper nanoclusters (CuNCs). The catalytic activity of CuNCs toward the oxidation of the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine by H2O2 is remarkably decreased in the presence of sulfide. Based on this finding, a colorimetric assay was developed for the rapid determination of sulfide. Best operated at a wavelength of 652 nm, it has a 0.5 μM detection limit. The method is highly selective and has been successfully applied to the quantification of sulfide in environmental water samples.
Graphical abstract The catalytic activity of CuNCs toward the oxidation of 3,3′,5,5′-tetramethylbenzidine by H2O2 is remarkably decreased in the presence of sulfide ions. This finding has been applied to design a method for colorimetric quantification of sulfide ions in environmental samples.
DNA-based logic gates promote the development of molecular computing and show enormous potential in the fields of nanotechnology and biotechnology. Dumbbell oligonucleotides(DNA) with poly-thymine(poly-T) loops and a nicked random double strand have been demonstrated to be an efficient template for the formation of fluorescent copper nanoclusters(Cu NCs) in our previous work. Herein, a new platform technology is presented with which to construct molecular logic gates by employing Cu NCs probe as... 相似文献
A facile, one-pot green method is presented for the preparation of water-soluble luminescent copper nanoclusters (Cu-NCs) from copper dichloride and cysteine as the precursor and stabilizer, respectively. The Cu-NCs are characterized by high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, fluorescence, UV–Vis, and Raman spectroscopy. The Cu-NCs have an average size of 3.5 nm and are stable in aqueous solution at least for 2 weeks. Under photo excitation with 365 nm light, the Cu-NCs display strong green fluorescence with the maximum of emission at 490 nm and a quantum yield of 5.6 %. Fluorescence is quenched by Cr(VI) ion, and this effect was exploited to develop a highly selective method for the determination of Cr(VI). The detection limit of this probe is as low as 43 nM.
Graphical Abstract A facile, one-pot, “green” synthetic route was developed for preparing water-soluble luminescent copper nanoclusters (CuNCs) by using copper chloride and cysteine as the precursor and stabilizer, respectively. Their fluorescence is quenched by Cr(VI) ion, and this is exploited in a sensitive assay for Cr(VI) ions.
Ultrasmall water-soluble silver nanoclusters are synthesized, and their properties are investigated. The silver nanoclusters have high colloidal stability and show fluorescence in the red. This demonstrates that like gold nanoclusters also silver nanoclusters can be fluorescent. 相似文献
Ordered silver iodide nanoclusters inside zeolite Y host were prepared by using a thermal diffusion method. The Y-AgI samples were characterized with powder X-ray diffraction, differential thermal analysis, X-ray photoelectron spectroscopy, adsorption technique and chemical analysis. The results show that silver iodide nanoclusters were situated in the ordered cages of the zeolite Y host. The results on the luminescence of the nanocomposites Y-AgI suggest that when the sizes of silver iodide nanoclusters are were very small, non-radiation surface recombination exceeds radiation process and the luminescence efficiency increases as the size of the silver iodide nanoclusters increaseds As the sizes of AgI nanoclusters increased, non-radiative surface recombination effect become equal to the radiation effect of the excitons. As the size of the nanoclusters of AgI in zeolite host further increases, the surface recombination of the nanoclusters becomes a major process. 相似文献