Journal of Fluorescence最新文献

In this study, a dual-ratiometric optical probe utilizing europium-doped carbon dots (Eu-CDs) was developed for simultaneous fluorescent and colorimetric detection of tetracycline (TC). The Eu-CDs complex was synthesized through a hydrothermal approach. Upon coordination with Eriochrome Black T (EBT), the Eu-CDs complex exhibits a distinct magenta coloration. Introduction of TC triggers a ligand displacement reaction, resulting in color transition from magenta to blue, resulting in ratiometric colorimetric visual detection. Meanwhile, the TC-bound EBT-CDs@Eu complex emits ratiometric fluorescence change. A ratiometric fluorescence detection method was established for TC based on the absorbance-energy transfer-emission (AETE) mechanism, culminating in the successful design of a dual-ratiometric optical probe. The colorimetric assay demonstrated a detection limit (LOD) of 20.5 nM for TC. Furthermore, the practical applicability of this sensor was validated through successful TC detection in aquaculture samples, highlighting its potential for real-world monitoring applications.

Levofloxacin (LEV) and ciprofloxacin (CIP) are widely common antibiotics. However, their misuse can lead to bacterial resistance and pose significant risks to both environment and human health. To address this issue, we synthesized and characterized two novel fluorescent composite materials: Fe₃O₄/HAP/Eu and Fe₃O₄/HAP/Tb. Fe₃O₄/HAP/Eu was designed for detection of LEV, whereas Fe₃O₄/HAP/Tb was developed for detection of CIP. The results showed that Fe₃O₄/HAP/Eu exhibited optimal excitation and emission wavelengths of 394 nm and 624 nm, respectively, with the fluorescence lifetime of 0.77 µs and the fluorescence quantum yield of 6.61%. Fe₃O₄/HAP/Tb performed optimal excitation and emission wavelengths of 370 nm and 551 nm, respectively, with the fluorescence lifetime of 1.06 µs and the fluorescence quantum yield of 8.28%. In terms of application, the linear range for detection of LEV was 1-50 µM, with detection limit of 0.67 µM. For CIP, linear range was 0.1-60 µM, and the detection limit was 0.086 µM. The two types of fluorescent composite provided reliable approach for detecting trace amounts of LEV and CIP in food. It demonstrated significant potential for practical applications in the fields of environment, food and medicine.

The breakthrough of high-power lasers urged the effective light quenching materials for safeguarding eyes,sensors and photo detectors. Encountered exploration of novel carbon dots to manipulate the ray of light at a modest price. Nonetheless, a carbon dot suffers from a large spectral range detection of a ray of light, so the research has been devoted to exploring the materials to cover different spectral ranges. This article reports a novel dual-photon emissive carbon dot with large spectral emission coverage with an effortless preparation strategy. The rapid fabrication procedure constituted with dualcolour emissive carbon dots(MCCD) in a single solvent with utilization of biomass source. We have identified the mono-solvent effect induced dual emissive carbon dots observed in fluorescence spectroscopy. The fluorescence carbon particle displays the nature of excitation-independent behaviour, with an average granule size of 16.93 nm, result obtained via Transmission electron microscopy. The carbon structure suffered from the lower carbonization temperature with rapid microwave treatment, causing a turbostratic carbon structure. The dual colour contains with NIR region bright red emission solution tested against Z-scan non-linear properties, it exposes the excited state absorption involved in two-photon absorption. It offers an approach for optical limiting behaviour, with threshold reaches up to 0.53 × 10^- 10 and 4.54 × 10¹² W/m² was observed for MCCD. These result in a gateway for eco-friendly carbon dots into an optical limiting appeal.

Four rare-earth complexes were prepared using Eu³⁺ and Tb³⁺ as central rare-earth ions and benzoic acid, furoic acid, α-thenoyltrifluoroacetone, and phenanthroline as organic ligands, and a four-channel fluorescent sensor array was constructed for the identification of triphenylmethane drugs. The four sensing units have different degrees of fluorescence response to six triphenylmethane drugs. The fluorescence quenching of Eu(III) complex by malachite green and Tb(III) complex by methyl violet were confirmed to be the FRET effect. After five parallel experiments, a 4 × 6 × 5 fluorescence data matrix was obtained, and the linear discriminant method were used to distinguish six triphenylmethane drugs at 0.1, 1.0, and 10 µmol L⁻¹ and mixed triphenylmethane drugs at 1.0 µmol L⁻¹ with an accuracy rate of 100%. The array achieved the identification of triphenylmethane drugs in fish samples with accuracy rate of 97.4%.

Hydrogen sulfide (H₂S) functions as a critical gaseous signaling molecule, and dysregulated levels are linked to various pathological conditions, such as diabetes, cardiovascular disorders, Alzheimer's disease, and malignant tumors. To facilitate disease monitoring and improve the understanding of related mechanisms, it is imperative to establish a rapid and precise method for detecting H₂S. In this work, we have designed a new near-infrared fluorescent probe, designated TPA-YL, for H₂S sensing. TPA-YL probe utilizes triphenylamine thiophene dye as a fluorophore, and 2,4-dinitrobenzenesulfonyl (DNS) as the response site for H₂S. In the presence of H₂S, the responsive group in TPA-YL undergoes thiolysis, and near-infrared fluorescence from the fluorophore is "turned on". The resulting fluorescence signal exhibits a good linear relationship with H₂S up to 50 µM (limit of detection, 17 nM). The advantages of TPA-YL include: a long emission wavelength (642 nm); a large Stokes shift (188 nm); high selectivity; as well as remarkable sensitivity (under physiological conditions). Furthermore, the TPA-YL probe has been effectively applied for visualizing both externally supplied and internally generated H₂S in HeLa cells via fluorescence imaging. Thus, this probe provides a promising strategy for studying the role of H₂S in intricate physiological and pathological mechanisms. We develop a novel near-infrared fluorescent probe (TPA-YL) for the detection of H₂S. In the presence of H₂S, the responsive group in TPA-YL undergoes thiolysis, and near-infrared fluorescence from the fluorophore is "turned on". TPA-YL enables H₂S detection in both in vitro and in vivo settings.

Oral squamous cell carcinoma (OSCC) remains a challenging malignancy due to poor drug efficacy and adverse effects. Resveratrol (RV) shows anti-OSCC potential but suffers from low solubility and bioavailability. To address this, a multifunctional polymer hybrid nanoparticle-poly(lactic-co-glycolic acid) (PLGA) modified with compound 1 and 4-(trimethoxysilyl)butanoic acid (TMSBA), and co-loaded with compound 2 and resveratrol (RV) (1-PLGA-TMSBA@2@RV)-was developed for fluorescence-responsive ferroptosis-associated therapy and pathological ion detection. The material exhibited high fluorescence selectivity toward OSCC-related GSH⁻ and Fe³⁺ ions, with quenching efficiencies of 98% and 92.9%, and a GSH⁻ detection range of 10⁻⁷-10⁻² M (R² = 0.9944) and Fe³⁺ detection limit of 10⁻⁶ M. CCK-8 assays showed RV-NPs significantly inhibited CAL-27 cell proliferation, outperforming free RV (53.8%), with blank carriers demonstrating good biocompatibility. qRT-PCR revealed RV-NPs downregulated ferroptosis regulator SLC7A11 by 71.2%, suggesting a ferroptosis-mediated antitumor mechanism. This nanoplatform offers an integrated approach for enhanced OSCC therapy and real-time pathological ion detection.

The current study describes the synthesis and characterization of AgNPs stabilized with a diester-based cationic gemini surfactant (C₁₂-E2O2-C₁₂), and their interaction behavior with protein. The main aim of the study was to explore how the surfactant-coated nanoparticle surface controls the binding and structural response of porcine serum albumin (PSA), acting here as the model protein. Synthesized C₁₂-E2O2-C₁₂-AgNPs were characterized by a spherical morphology, average size of 12.57 nm, and positive surface potential of + 19.50 ± 8.55 mV, confirming their stable dispersion. UV-Vis and fluorescence spectroscopic analyses revealed spontaneous and moderate binding of PSA to the nanoparticles, with the binding constants of 3.44 × 10⁴ M⁻¹ and 7.40 × 10⁴ M⁻¹, respectively. The interaction was mainly driven by electrostatic and hydrophobic forces, leading to changes in the secondary structure of PSA, as supported by FTIR and deconvolution of the amide I band. Surface tension studies further confirmed PSA-induced modulation of the interfacial property of the C₁₂-E2O2-C₁₂-AgNPst system, with a decrease in CMC and rise in molecular area (A_min), suggesting protein-mediated reorganization at the interface. Overall, these results offer new insights into the role of gemini surfactant-coated AgNPs in modulating protein-nanoparticles interactions relevant for biomedical and biosensing applications.

This work examines bifenthrin (BIF) and resmethrin (RES), two pyrethroid insecticides used in the agricultural area of Niayes, focusing on their analysis in spiked surface and groundwater. Both pesticides have an optimal pH of 7 and an optimal MeOH concentration of 20% in water. Comparing fluorescence intensities across different solvents shows that it is higher in H₂O-MeOH for both BIF and RES. Calibration curves ranging from 0.15 to 7.5 µg mL^- 1 were established in different solvents, and their linearity was confirmed through variance analysis. The method measurement is highly sensitive, with LOD values ranging from 0.12 to 1.76 ng mL^- 1 and LOQ values ranging from 0.35 to 5.82 ng mL^- 1, depending on the medium and pesticide. The interday precision values range from 1.8 to 4.3%, attesting to the intermediate precision of the results. The mean recovery results for the determination of the two pesticides in spiked natural water were satisfactory, ranging from 96.2 to 103.7%, with an intraday precision value less than 5% attesting to the repeatability of the results. Moreover, the interference study shows the robustness of the method.