Journal of Fluorescence最新文献

This study provides a comprehensive theoretical and experimental analysis of the interactions between 3-(4-{9-[4-(3, 4-dicyanophenoxy) phenyl]-9 H-fluoren-9-yl}phenoxy)phthalonitrile and metal chlorides, focusing specifically on nickel chloride (NiCl₂) and cobalt chloride (CoCl₂). Combining Density Functional Theory (DFT) calculations with various spectroscopic techniques and electrochemical methods, the research explores the binding mechanisms and the electronic changes induced by the metal chlorides. DFT calculations, using the B3LYP functional and a 6-31G basis set for ground-state optimization, revealed significant modifications in the HOMO-LUMO energy gap upon coordination with the metal chlorides, indicating notable shifts in the compound's electronic properties. Experimental data from UV-visible and fluorescence spectroscopy confirmed the formation of metal-ligand complexes, with observed shifts in absorption and emission spectra that corresponded with theoretical predictions. Further electrochemical insights were obtained through cyclic voltammetry, demonstrating an enhanced electron transfer process due to the metal ion interactions. These findings highlight how the inclusion of NiCl₂ and CoCl₂ significantly influences the electronic and optical characteristics of the phthalonitrile compound, suggesting their potential applications in optoelectronic devices and catalytic systems. This multidisciplinary approach provides a deeper understanding of metal-organic interactions and emphasizes the compound's promise in material science applications.

In this study, we report the synthesis and photophysical evaluation of hydrazone 7 and azo 9 compounds of a thiazolo[3,2-a] indole derivative 5; latter synthesized as per our earlier report. Of the two compounds, the azo compound 9 showed exceptional selectivity and sensitivity as a dual sensor for detecting Fe²⁺ and Cu²⁺ ions via a turn-off fluorescence mechanism with limit of detection 0.09 µM and 0.14 µM respectively which are much lower than the US Environmental Protection Agency (EPA) guideline, 5.36 µM for Fe²⁺ and WHO guideline, 31.5 µM for Cu²⁺ in the drinking water. DFT calculations revealed that both Fe²⁺ and Cu²⁺ complexes with compound 9, and possess low HOMO-LUMO gap of 1.63 eV and 2.94 eV respectively. The binding stoichiometry for both metals was determined to be 1:1 by Job's plot. Stern-Volmer plot (plotted after applying correction to emission intensity), which showed a linear pattern, and fluorescence lifetime measurements indicated primarily a static quenching mechanism for both ions. The chemosensor 9 demonstrated exceptional reversibility and restorability in detecting both Fe²⁺ and Cu²⁺, highlighting its potential for practical applications.

Cadmium is a highly toxic heavy metal that poses severe health risks, particularly to children, due to their increased hand-to-mouth behavior and higher gastrointestinal absorption rates. Once absorbed, cadmium primarily accumulates in the kidneys, leading to progressive toxicity and renal dysfunction. Moreover, it has been linked to neurodevelopmental impairments and cognitive decline, raising significant concerns about its long-term impact on pediatric health. This review provides a comprehensive analysis of cadmium-induced toxicity, with a particular focus on its detrimental effects on kidney function and neurodevelopment in children. Additionally, it highlights recent advancements (2021-2024) in fluorometric and colorimetric chemosensors for Cd²⁺ detection, emphasizing their applications in biological and environmental monitoring. The obtained detection limit of these chemosensor is significantly lower than the maximum permissible level of 3 µg/L for Cd²⁺ ions in drinking water, as recommended by the U.S. Environmental Protection Agency (EPA). By covering the latest research, this review aims to enhance understanding of cadmium exposure risks while promoting the development of highly sensitive and efficient detection methods for improved public health protection.

A rapid and sensitive ratiometric fluorescence nanosensor for the detection of norfloxacin was obtained, where the yellow-emitting CdTe quantum dots (QDs) were as an internal reference and aluminium ion (Al³⁺) chelated on the QDs surface as the sensing unit. The nanosensor was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. As the concentration of norfloxacin increased, the sensor exhibited a continuous fluorescence color transition from yellow to blue. The CdTe-Al³⁺ QDs sensor demonstrated a low limit of detection of 6.6 nM. The ratiometric fluorescence sensor was also integrated with a smartphone color recognizer for visual and quantitative detection of norfloxacin with a limit of detection of 1.57 µM. This sensing platform exhibits excellent sensitivity, selectivity, and anti-interference performance, and it has great potential for on-site and quantitative analysis.

A novel, highly sensitive fluorometric method for D-penicillamine (D-PA) detection has been developed, addressing critical needs in therapeutic drug monitoring. D-PA, a crucial chelating agent used in treating Wilson's disease, rheumatoid arthritis, and heavy metal poisoning, requires precise quantification due to its narrow therapeutic window and potential toxicity. The proposed method introduces an innovative sensing platform utilizing red-emissive carbon dots (R@CDs) and cobalt ions, which enables exceptional analytical performance through a sophisticated dual-quenching mechanism. The detection strategy involves cobalt ions initially enhancing the fluorescence of R@CDs. Upon D-PA addition, two synergistic quenching effects occur: competitive displacement of cobalt ions from the carbon dot surface and formation of a yellow-colored D-PA-cobalt complex, inducing an inner filter effect. Comprehensive characterization and mechanistic investigation revealed the intricate molecular interactions governing this detection process. The developed method demonstrated excellent analytical performance, exhibiting excellent linearity (R² = 0.9971) and an ultra-low limit of detection of 0.0041 µM. Rigorous validation was conducted through application to rat plasma samples, successfully quantifying D-PA in both healthy and diabetic animal models. Pharmacokinetic analysis unveiled variations in drug disposition between healthy and diabetic rats, highlighting the method's potential for personalized therapeutic monitoring.

Breast cancer continues to be a complicated and pervasive health issue that impacts women worldwide. Fluorescent nanoparticles, in particular, provide significant potential for imaging and drug delivery in cancer cells. We describe the utilization of o-phenylenediamine carbon nanodots (OPD@CD) as fluorescent agents for in vitro imaging and drug delivery of breast cancer cells. The surface of OPD@CD was modified with the tyrosine kinase inhibition anticancer drug - erlotinib. The drug specifically targets human breast cancer cell lines (MCF-7) that overexpress the epidermal growth factor receptor (EGFR). The confocal luminescence microscopic photographs exhibit sufficient luminescence staining in MCF-7 cells.

This study employs synchronous fluorescence spectroscopy to analyze the biochemical composition and quality of one of the most commercialized tropical fruit juice of mango. Commercially available juices in comparison with pure mango pulp from Anwar Ratol and white Chaunsa cultivars showed distinct bands oweing to the emission from tryptophan, phenolic compounds, riboflavin and chlorophyll, emphasizing the nutritional and phytochemical richness of mango pulp. Dilutions of pure mango pulp significantly decreased overall band intensities, indicating reduced nutritional content that can be marked in water adulterated samples. Similarly color adulteration resulted not only notable decrease in band intensity but deformed peaks in the range of 410-530 nm, Thermally treated mango pulp maintained molecular structure and fluorescence intensity till 80 ^oC, while higher temperatures may led to the breakdown of phenolic compounds and enhanced fluorescence emission. These findings highlight the effectiveness of synchronous fluorescence spectroscopy in assessing juice quality, optimizing processing conditions and ensuring product authenticity and consumer safety.

In this study, a benzothiazole-based fluorescent probe, (methyl (E)-2-(3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-me$thylbenzylidene) hydrazine-1-carboxylate) (DYH), was investigated for the possibility of sensitive detection of potentially threatening explosives (2, 4, 6-trinitrophenol) TNP and its application. The probe exhibited blue-green fluorescence in methanol solution and its intensity decreased significantly with increasing TNP concentration, achieving a fluorescence quenching efficiency of up to 99.77%. The binding between the probe and TNP followed a stoichiometric ratio of 1:1, achieving a detection limit of approximately 2.1 × 10^-7 M, indicating its high detection sensitivity. Further studies have shown that the DYH was excellent in rapidly detecting TNP, and its application in natural water samples and solid phase papers validated its usefulness. In addition, this study successfully combined the probe DYH with smartphone technology, establishing a convenient smartphone sensing platform that provides a more convenient solution for rapid and real-time detection of TNP.

Accurately determining the viability of cells is crucial for in vitro cell research. Fluorescence-based live/dead cell staining is a highly desirable method to assess cell viability and survival in in vitro studies. We describe a green synthesis method to create red-emissive CQDs from the medicinal and edible herb Echinophora tenuifolia using microwave irradiation. We observed that the biocompatibility and photostability of the CQDs are superior. The antioxidant capacity of the CQDs and the plant extract were also investigated using different chemical methods (DPPH, ABTS, CUPRAC, FRAP, PBD, and MCA). The antioxidant capacity of the CQDs was similar to that of the extract of E. tenuifolia. Cytotoxicity studies indicate that while the CQDs are not toxic to L929, they exhibit significant toxicity towards HepG2 cells. The CQDs exhibited a strong negative zeta potential (-44.0 mV), which contributed to their selective interaction with dead cells while being repelled by viable cells with intact membrane potentials. The optimal concentration for effective, non-toxic imaging was determined to be 25 µg/mL, as lower concentrations did not produce detectable fluorescence. Differential staining experiments confirmed that CQDs selectively stained dead cells, with red fluorescence observed under the Texas Red filter. Moreover, CQDs exhibited favorable fluorescence intensity and stability, which may offer advantages for long-term and reliable bioimaging applications. In vitro studies on HepG2 and L929 cell lines revealed that the red-emissive CQDs from E. tenuifolia can be potentially used in bioimaging.

A practical and highly selective reactive probe for hydrogen sulfide (H₂S), designated as 4-(7-(4-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)oxy)phenyl)benzo[c][1,2,5]thiadiazol-4-yl)-N,N-diphenylaniline (BTD), was synthesized through the covalent attachment of the 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) unit to 4-(7-(4-(diphenylamino)phenyl)benzo[c][1,2,5]thiadiazol-4-yl)phenol (BP-OH). The structure of probe BTD was characterized using IR, NMR, and HRMS. Experimental results demonstrate that the fluorescence of BTD significantly increases upon the introduction of H₂S, resulting in a distinct color change from colorless to bright orange-red. The detection capability of BTD for H₂S was assessed using UV-visible absorption and fluorescence emission spectroscopy. The probe shows significant fluorescence enhancement and can detect H₂S quantitatively over a concentration range of 0 to 14 μM, with a low detection limit of 44.85 nM. Furthermore, BTD exhibits excellent recovery rates and accuracy, indicating its practicality for H₂S analysis in real samples.