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Detection of Tetracycline in Water Using Glutathione-protected Fluorescent Gold Nanoclusters
摘要： Tetracycline (Tc), a widely used antibiotic, is one of the major pollutants in water. Herein, glutathione (GSH)-protected Au nanoclusters (GSH-AuNCs) were prepared to detect Tc. The fluorescence quenching ratio of GSH-AuNCs shows an excellent linear response against tetracycline in the concentration range of 50 μg/L – 50 mg/L with the detection limit of 5.31 μg/L. For the test paper prepared by GSH-AuNCs, 1 mg/L Tc caused a significant difference that could be recognized by the naked eye. The method exhibited good selectivity and excellent recovery when applied to a tap water sample. The method has the potential for Tc detection in real samples.
关键词： tetracycline detection,Au nanocluster,glutathione,recovery experiment,quenching ratio
更新于2025-11-19 16:56:35
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A Fluorescence Light-up Silver Nanocluster Beacon Modulated by Metal Ions and Its Application in Telomerase Activity Detection
摘要： DNA-templated silver nanoclusters (DNA-AgNCs) have been extensively studied in recent years. The enhancement of fluorescence emission from the DNA-AgNCs is still being explored. Herein, we report a new study on the fluorescence enhancement of DNA-AgNCs induced by metal ions. The enhancement is greatly dependent on the primary sequence and secondary structure of DNA strands. Thus, a label-free AgNCs-based molecular beacon (MB) is explored for the detection of telomerase activity. Nonfluorescent MB-AgNCs in phosphate buffer emit a dramatic red fluorescence when Mg2+ is introduced, whereas Mg2+ has a limited effect on the weak fluorescence of DNA-AgNCs when the hairpin structure of MB is opened. Telomerase primer (TP) can be elongated by telomerase, resulting in the unfolding of MB via strand displacement reaction. Based on the different brightnesses of AgNCs produced by the two DNA templates, telomerase activity is detected. MB-AgNCs sensing platform provides a simple and low-costing method to detect telomerase activity and shows a great potential in the construction of cost-effective probes for biomolecular detection.
关键词： telomerase detection,DNA,fluorescence enhancement,silver nanocluster,metal ions
更新于2025-09-23 15:23:52
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Sensing of iron(III)-biomolecules by surfactant-free fluorescent copper nanoclusters
摘要： Surfactant-free copper nanoclusters (sf-CuNCs) synthesized in the absence of external stabilizer, could be promising fluorescence biosensors because of the presence of relatively exposed surfaces that may ease coupling with biomolecules. This article shows that sf-CuNCs are effective fluorescence sensor of iron(III)-biomolecules: hemin, cytochrome C (cyt C), and ferritin. Although, sf-CuNCs are found to be weaker sensor of aqueous Fe3+ (Stern-Volmer constant (KSV) 3.0 × 103 M?1 and limit of detection (LOD) up to 2 μM) compared to other capped CuNCs, however, the sensing ability markedly increases in the presence of Fe(III)-biomolecules. KSV (LOD) are 5.3 × 104 M?1 (0.8 μM), 9.0 × 105 M?1 (68 nM), 1.6 × 106 M?1 (16.50 nM), respectively for cyt C, hemin and ferritin. We carried out detailed mechanistic investigations of the quenching process using time-resolved fluorescence, zeta potential and transmission electron microscopy (TEM) measurements. We found that fluorescence quenching is associated with complexation of Fe3+ with CuNCs which changes zeta potential of the sf-CuNCs and leads to aggregation of CuNCs. Moreover, fluorescence quenching, zeta potential and aggregation of CuNC can be reversed by addition of vitamin C which is a very strong chelator and reducing agent of Fe(III). Vitamin C reduces Fe(III) to Fe(II) and promotes disassembly of CuNCs-aggregates to regenerate fluorescence intensity. Since, the sensing is primarily governed by complex formation with Fe3+, absence of ligands on the surface of sf-CuNCs may be detrimental to quenching to aqueous Fe3+ but favors binding with the biomolecules.
关键词： Iron sensing,Copper nanocluster,Proteins,TEM,Fluorescence
更新于2025-09-23 15:23:52
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A unique FRET approach toward detection of single-base mismatch DNA in BRCA1 gene
摘要： Early detection of mutation carriers in predisposing genes such as BRCA1 plays an important role in disease prevention. This work developed a quantum dots-based (QDs-based) fluorescence resonance energy transfer (FRET) technique for the detection of single-base mismatch DNA in BRCA1 gene. The FRET between QDs as the donor and silver nanocluster (AgNCs) as the acceptor was designed by the strong interaction between CdTe QDs with appropriate size and dsDNA through binding to its major groove. The dsDNA was formed by the hybridization of ssDNA labeled to AgNCs with target DNA, which introduced CdTe QDs into the major grooves to place the AgNCs in close proximity to the QDs. The complementary and single-base mismatch DNA led to obviously different FRET signals. The FRET signal linearly correlated to the concentration of single-base mismatch DNA in the range of 1.5 × 10^{-10}–1.0 × 10^{-6} mol L^{-1}. The proposed method showed a detection limit of 80 pmol L^{-1} and the sensitivity comparable to the previously reported assays, indicating promising potential for single nucleotide polymorphisms diagnosis in clinical application.
关键词： Silver nanocluster,DNA,Single-base mismatch,Quantum dots,FRET,Fluorescence analysis
更新于2025-09-23 15:23:52
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Potassium triiodide-quenched gold nanocluster as a fluorescent turn-on probe for sensing cysteine/homocysteine in human serum
摘要： A fluorescent sensing platform using KI3-quenched bovine serum albumin stabilized gold nanoclusters has been designed and used as a fluorescent probe for the turn-on detection of homocysteine/cysteine (Cys/Hcy). The fluorescence of gold nanoclusters was quenched by iodine. The fluorescence of quenched gold nanoclusters was effectively switched on by Cys/Hcy devoid of the interference of glutathione. The transmission electron microscopy image, X-ray photoelectron spectroscopy analysis, time-correlated single photon counting analysis, and dynamic light scattering data confirmed the aggregation-induced quenching of fluorescence of gold nanoclusters by iodine. The turn-on response of Cys/Hcy shows two linear ranges from 0.0057 to 5 μM and from 8 to 25 μM, with a limit of detection of 9 nM for cysteine and 12 nM for homocysteine. Real samples were analyzed to monitor Cys/Hcy added to human serum. The fluorescence turn-on response of the probe on a paper strip in the presence of Cys/Hcy was studied.
关键词： Cysteine,Fluorescence turn on,Gold nanocluster,Bovine serum albumin,Iodine,Homocysteine
更新于2025-09-23 15:22:29
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Self-Referenced Ratiometric Detection of Sulfatase Activity with Dual-Emissive Urease-Encapsulated Gold Nanoclusters
摘要： In this study, on the basis of the biomineralization capability of urease, a facile, one-step, and green synthetic method has been proposed for the fabrication of gold nanoclusters (AuNCs). The prepared urease-encapsulated AuNCs (U-AuNCs) exhibited strong red fluorescence emission (λem = 630 nm) with a quantum yield as high as 17%. Interestingly, at a low concentration, the U-AuNC solution was found to be a dual-emissive system with the blue emission of the dityrosine (diTyr) residues of urease and the red emission of the embedded AuNCs. Further experiments demonstrated that p-nitrophenol (PNP) can selectively suppress the 410 nm emission of the diTyr residues of U-AuNCs without affecting the red emission of the U-AuNCs. The fluorescence quenching mechanism between U-AuNCs and PNP was systematically studied, and the leading role of the inner filter effect (IFE) was identified. Additionally, based on the sulfatase-catalyzed hydrolysis of p-nitrophenyl sulfate (PNPS) to release PNP, a self-referenced ratiometric detection method for sulfatase, which plays a crucial role in sulfur cycling, degradation of sulfated glycosaminoglycans and glycolipids, and extracellular remodeling of sulfated glycosaminoglycans, was developed by using dual-emissive U-AuNCs as the signal readout, in which the diTyr residues served as the probe and the AuNCs functioned as the internal reference. This IFE-based ratiometric sensing strategy showed a good linear relationship over the range of 0.01-1 U/mL (R2 = 0.997). The detection limit for sulfatase activity was 0.01 U/mL. The developed protocol was successfully used to detect sulfatase activity in human serum samples. The simplicity, rapidness, low cost, high credibility, good reproducibility, and excellent selectivity of the detection platform serve as an inspiration for further applications of fluorescent AuNCs in chemo/biosensing.
关键词： dityrosine,inner filter effect,gold nanocluster,ratiometric detection,sulfatase
更新于2025-09-23 15:22:29
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Ether-soluble Cu53 Nanoclusters as an Effective Precursor of High-quality CuI Films for Optoelectronic Applications
摘要： An effective strategy is developed to synthesize high-nuclearity Cu clusters, [Cu53(RCOO)10(C≡CtBu)20Cl2H18]+ (Cu53), which is the largest Cu(I)/Cu(0) cluster reported to date. Cu powder and Ph2SiH2 are employed as the reducing agents in the synthesis. As revealed by single-crystal diffraction, Cu53 is arranged as a four-concentric-shell Cu3@Cu10Cl2@Cu20@Cu20 structure, possessing an atomic arrangement of concentric M12 icosahedral and M20 dodecahedral shells which popularly occurs in Au/Ag nanoclusters. Surprisingly, Cu53 can be dissolved in diethyl ether and spin coated to form uniform nanoclusters film on organo-lead halide perovskite. The cluster film can subsequently be converted into high-quality CuI film via in-situ iodination at room temperature. The as-fabricated CuI film proves to be an excellent hole-transport layer for fabricating highly stable CuI-based perovskite solar cells (PSCs) with 14.3% of efficiency.
关键词： CuI film,Cu nanocluster,Alkynyl,Perovskite solar cells,Superatoms
更新于2025-09-23 15:21:21
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Sensors Based on Metal Nanoclusters Stabilized on Designed Proteins
摘要： Among all new nanomaterials, metal nanoclusters (NCs) have attracted special attention due to their interesting optical properties, among others. Metal NCs have been recently studied and used as sensors for different analytes. However, there is a need to explore the potential of these new sensors in a systematic manner and to develop new systems to broaden the possibilities that sensing offers to the industry. In this work, we show the potential use of repeat protein scaffolds as versatile templates for the synthesis and stabilization of various metal NCs, speci?cally Au, Ag, and CuNCs. The resulting protein-metal NCs hybrids are evaluated as sensors for different stimuli such as temperature, ions, or reactive oxygen species (ROS). Among the three protein-metal NCs, all performed nicely as temperature sensors, AuNCs responded to metal ions, and AgNCs were able to detect ROS.
关键词： nanosensor,ROS sensors,metal nanocluster,protein design,temperature sensor,metal sensors,?uorescent probe
更新于2025-09-23 15:21:21
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Preparation and comparison of Fe3O4@graphene oxide nanoclusters for analysis of glimepiride in urine by surface-assisted laser desorption/ionization time-of-flight mass spectrometry
摘要： Graphene oxide (GO) has the ability to absorb certain compounds, and it can be modified with functional groups for different purposes; for instance, iron oxide (IO) nanoparticles can be used to concentrate analyte by a magnet. Recently, many kinds of GO have been developed, such as single-layer GO (SLGO), two-to-four layers of GO (i.e., few-layer GO, FLGO2–4), and four-to-eight layers of GO (i.e., multi-layer GO, MLGO4–8). However, the abilities of these layered GO coated with IO nanoparticles have not been investigated. In this study, we conducted a novel analysis of glimepiride by using layered GO-coated magnetic clusters of IO nanoparticles that were synthesized through a simple and facile emulsion-solvent evaporation method. The methodology is based on (i) enrichment of glimepiride using the layered GO-coated magnetic clusters of IO nanoparticles (IO@SLGO, IO@FLGO2–4, and IO@MLGO4–8), and (ii) rapid determination using magnetic cluster–based surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOFMS). We found that IO@MLGO4–8, the magnetic cluster with the greatest number of GO layers, had the best limit of detection (28.6 pmol/μL for glimepiride). The number of GO layers played a significant role in increasing the sensitivity of the SALDI-MS, indicating that the size of GO in the magnetic clusters contributed to the desorption/ionization efficiency. To the best of our knowledge, this is the first study to enrich glimepiride using magnetic clusters of different GO types and to show that the glimepiride in HLB purified urine adsorbed by magnetic clusters can be analyzed by SALDI-TOFMS.
关键词： Mass spectrometry,Iron oxide,Glimepiride,Nanocluster,SALDI,Graphene oxide
更新于2025-09-23 15:21:01
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Ag2Au50(PET)36 Nanocluster: Dimeric Assembly of Au25(PET)18 Enabled by Silver Atoms
摘要： Assembly of atomically precise metal nanoclusters is now in the research spotlight, which offers exciting opportunities to gain fundamental insights into the hierarchical assembly of nanoparticles. However, it is still extremely challenging for controllable assembly of individual nanoclusters at a molecular- or atomic-level. Herein we report the dimeric assembly of Au25(PET)18 (PET = 2-phenylethanethiol), where two Au25(PET)18 monomers are bridged together by two Ag atoms to form the Ag2Au50(PET)36 dimer. The Ag2Au50(PET)36 dimer is an exclusive mesomer, which has not been found in any other chiral metal nanoclusters belonging to the racemic category. Furthermore, the Ag2Au50(PET)36 dimer is distinct from the Au25(PET)18 monomer on the optical, electronic, and catalytic properties. This study is expected to provide a feasible strategy to precisely modulate the assembly of metal nanoclusters with controllable structures and properties.
关键词： dimer,assembly,properties,Ag2Au50(PET)36,nanocluster
更新于2025-09-23 15:21:01