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A “turn-on” fluorometric assay for kanamycin detection by using silver nanoclusters and surface plasmon enhanced energy transfer
摘要： A rapid method is described for the determination of the antibiotic kanamycin. It integrates a kanamycin-binding aptamer and surface plasmon enhanced energy transfer (SPEET) between DNA-templated silver nanoclusters (AgNCs) and gold nanoparticles (AuNPs). The AgNCs and AuNPs were selected as energy donor and energy acceptor, respectively. The aptamer was designed to regulate the energy transfer between AgNCs and AuNPs. The aptamer was adsorbed on the AuNPs. Upon addition of kanamycin, the aptamer-kanamycin complex is formed, and this results in the aggregation of the AuNPs in high salt concentration, the formation of a blue coloration, and in the suppression of the SPEET process. The fluorescence of the AgNCs (with excitation/emission peaks at 560/600 nm) is quenched by the aptamer protected AuNPs in absence of kanamycin. The fluorescence on addition of kanamycin increases linearly in the 5 to 50 nM concentration range, with a lower detection limit of 1.0 nM (at S/N = 3). The assay can be performed within 30 min. It was successfully applied to the determination of kanamycin in spiked milk samples, and recoveries ranged between 90.2 and 95.4%. Conceivably, the strategy has a wide potential for screening by simply changing the aptamer.
关键词： Ag NCs,Milk analysis,Antibiotics detection,Au NPs,Food safety,Aptasensor
更新于2025-11-19 16:46:39
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Enzyme-free fluorometric assay for chloramphenicol based on double stirring bar-assisted dual signal amplification
摘要： An enzyme-free fluorometric assay is described that accomplishes dual signal amplification by making use of a two stirring bars. Two Y-shaped DNA probes were designed and placed on the bars. When the target (with chloramphenicol as model analyte) is added, it triggers target recycling and simultaneously catalyzes hairpin assembly (CHA). A large fraction of DNA primers is released by the analyte from the bar to the supernatant and open hairpins with G-quadruplex DNA sequence. The G-quadruplex can specifically bind thioflavin T (ThT) to emit fluorescence (with excitation/emission maxima at 445 and 485 nm) for quantification of chloramphenicol. An enzyme is not needed. ThT is added to the system as a fluorescent DNA probe. All this strongly reduces the cost for sensor construction and usage. The dual signal amplification steps occur simultaneously which reduces the detection time. The assay was successfully employed to the determination of CAP in spiked milk and fish samples within 60 min and with a 16 pM limit of detection (at S/N = 3).
关键词： Food safety,Antibiotics detection,Thioflavin T,Catalyzed hairpin assembly,Target recycling
更新于2025-11-19 16:46:39
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Rapidly detecting antibiotics with magnetic nanoparticle coated CdTe quantum dots
摘要： A reusable magnetic-quantum dot material (MNP–SiO2–QD) with good magnetic properties and high ?uorescence retention was successfully fabricated from linked magnetic nanoparticles and quantum dots. The resulting material can qualitatively and quantitatively detect four kinds of antibiotics and maintain high recovery rates.
关键词： reusability,antibiotics detection,fluorescence,magnetic nanoparticles,quantum dots
更新于2025-09-23 15:19:57
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Attomolar Detection of Low-Molecular Weight Antibiotics Using Midinfrared-Resonant Toroidal Plasmonic Metachip Technology
摘要： Plasmonic metamaterials can be used to enhance midinfrared sensors and detectors for immunosensing applications. The major challenge with them is to integrate these technologies in low-cost, compact, and promising platforms. As an emerging technique, we utilize toroidal resonant plasmonic metamaterials to develop an ultrasensitive label-free analytical platform for the detection of specific antibiotics in the midinfrared spectra. Taking advantage of the unique sensitivity of robustly squeezed electromagnetic fields in the toroidal plasmonic meta-atoms, we demonstrate that our proposed approach based on toroidal metastructures provides recognition of extremely-low-weight (approximately 0.6 KDa) biological targets at attomolar densities. We envisage that this understanding extends the capabilities of plasmonic metamaterials to analyze the presence of specific biological molecules and organisms with ultrahigh precision.
关键词： midinfrared sensors,Plasmonic metamaterials,ultrasensitive label-free analytical platform,antibiotics detection,toroidal resonant plasmonic metamaterials
更新于2025-09-11 14:15:04
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Design of a Highly-Stable Pillar-Layer Zn(II) Porous Framework for Rapid, Reversible, and Multi-Responsive Luminescent Sensor in Water
摘要： The Hard-Soft-Acid-Base (HSAB) and dual-ligand strategies have been used to construct a pillar-layer luminescent metal–organic framework (MOF) {[Zn2(TRZ)2(DBTDC-O2)]?DMAc}n (1), in which H2DBTDC-O2 = S,S-dioxodibenzothiophen-3,7-dicarboxylic acid and HTRZ = 1,2,4-triazole. Thanks to its high stability in water and quadrangle microporous channels, MOF 1 can be served as a platform of recyclable multi-responsive luminescent sensor for Fe3+, Al3+, SiF6 2–, Cr2O7 2–, nitrofurantoin (NFT), and nitrofurazone (NFZ) in water. This is the first MOF-based sensor for detecting SiF6 2– anion via luminescent enhancement effect. Significantly, 1 also represents a unique example to probe NFZ or NFT by using transition metal MOFs in water, which exhibits the most sensitive sensing ability for NFZ (Ksv = 5.2 × 104 M–1) and NFT (Ksv = 1.8 × 105 M–1) via luminescent quenching.
关键词： Multi-responsive,Metal–organic framework,Water stability,Antibiotics detection,Luminescent sensor
更新于2025-09-09 09:28:46