Journal of Fluorescence最新文献

Strontium orthogermanate (Sr₂GeO₄) doped with Mn⁴⁺ and Cu²⁺ phosphors were prepared by high temperature solid state reaction. All the prepared phosphors were crystallized in the orthorhombic lattice with space group Pbn2₁. The surface morphology of prepared phosphors contains irregular shaped objects with considerable agglomeration. The FT-IR and Raman profiles of the compositions gave characteristic bands belonging to GeO₄^4- tetrahedra. Photoluminescence profiles of Sr₂GeO₄: Mn⁴⁺ compounds are characterized by red emission at 647 nm upon excitation at 433 nm, while Sr₂GeO₄: Cu²⁺ compositions gave orange emission at 603 nm under excitation at 403 nm. The emission mechanism of Sr₂GeO₄: Mn⁴⁺ was explained by Tanabe-Sugano energy level diagram of Mn⁴⁺ ion. The CIE chromaticity coordinates, color purity (CP) and correlated color temperature (CCT) values were deduced. Thermoluminescence profiles are characterized and trap depth parameters were evaluated. These compositions may be useful in the manufacturing of cool and warm solid state lighting sources.

The detection of ferric ions (Fe³⁺) is of crucial importance in environmental monitoring and biomedical diagnostics. However, developing highly selective, sensitive, and environmentally friendly detection methods remains an important challenge. In this study, nitrogen-doped carbon quantum dots (N-CQDs) were green-synthesized as a novel and sustainable fluorescent sensor for Fe³⁺ detection. The synthesis was achieved via a one-pot hydrothermal method using licorice powder as a renewable carbon source and p-phenylenediamine as a nitrogen dopant. The synthesized N-CQDs display bright blue fluorescence, with a maximum emission at 436 nm when excited at 320 nm. They serve as a highly selective and sensitive fluorescent probe for Fe³⁺, showing a distinct fluorescence "turn-OFF" response. The sensor offers a linear range of 0 to 50 µM for Fe³⁺ detection, with a calculated limit of detection (LOD) of 0.346 µM. A notable aspect of this work is the demonstration of an "ON-OFF-ON" sensing paradigm. The fluorescence quenched by Fe³⁺ can be effectively restored ("turn-ON") by adding ascorbic acid, which reduces Fe³⁺. This "ON-OFF-ON" behavior emphasizes the specificity of N-CQDs towards Fe³⁺ to Fe²⁺. The practical applicability of the sensor was confirmed through successful detection of Fe³⁺ in complex real-world samples, including beer and human blood serum, achieving excellent recovery percentages (97.6% - 101.7%) and low relative standard deviations (RSD, 0.9% - 1.8%). Overall, this research presents an environmentally friendly N-CQD-based fluorescent sensor with a unique reversible fluorescence response "ON-OFF-ON" for Fe³⁺, holding great potential applications in environmental monitoring and biomedical diagnostics.

Viscosity plays a pivotal role in regulating diffusion, a process central to various biological functions. Its detection is crucial in diagnostics, disease detection, and food freshness identification. To probe such micro-viscosity changes in live cells, fluorescent molecular rotors (FMRs) are commonly employed. The study developed two benzothiazole-based fluorescent molecular rotors, BCN1 and BCN2, designed for viscosity sensing via the TICT mechanism. Both probes were structurally characterized by various techniques such as NMR, FTIR, HRMS, SCXRD and exhibited high sensitivity of 1.18 cP (BCN1) and 1.94 cP (BCN2) in methanol-glycerol mixtures. Photophysical studies revealed strong emission, large Stokes shifts, pH resilience, and minimal aggregation. Biocompatibility was confirmed through cytotoxicity assays, enabling successful application in live-cell imaging and food spoilage detection. Solid-state fluorescence probes enabled high-resolution latent fingerprint visualization across various substrates, revealing nine different features of three different levels of fingerprint analysis. DFT calculations supported their electronic properties. Collectively, BCN1 and BCN2 emerge as multifunctional probes with broad utility in biological, environmental, and forensic applications.

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 existence of microplastics in the environment is currently a significant worldwide concern. Microbeads found in personal care and cosmetic products (PCCPs) are one of the primary sources of microplastics, which pose a threat to human health and the environment. This study was designed to detect microplastics in a popular PCCP (facial scrub and face wash). Twenty products (10 facial scrubs and 10 face washes) were analyzed using Rhodamine B staining prepared in ethanol, distilled water, and acetone, followed by fluorescence microscopy. All samples tested positive for the presence of microplastics. The observed microplastics displayed orange, red, and green fluorescence and varied in shape, with most appearing irregular and fragmented. One- way ANOVA (F = 31.87, p = 0.0001) demonstrated that there was statistical difference between these solvents and ethanol (11.40 ± 5.03) provided the most effective staining results. FTIR analysis further confirmed that polystyrene and polyurethane as the most common polymers in facial scrubs, while ethylene-propylene copolymer and polystyrene were predominant in face washes. Additional polymers, including polyvinyl chloride, polypropylene, and polyethylene terephthalate, were also detected in some samples. This research highlights the occurrence of microplastics in facial scrubs and face washes and emphasizes the need for increased awareness and stronger regulatory measures to limit their use in cosmetic formulations.

A novel fluorescent Schiff base chemosensor, N'¹,N'⁶-bis((E)-3,5-dibromo-2-hydroxybenzylidene)adipohydrazide (DBSA), has been developed for the detection of Cobalt (II) ions. DBSA exhibits distinct fluorescence enhancement upon interacting with Co(II) ions via photoinduced electron transfer (PET). The developed sensor demonstrates a remarkable sensitivity, with the detection limits of 9.9 nM for Co(II) ions, which aligns well with the Environmental Protection Agency (EPA) regulatory thresholds for drinking water contaminants. Structural characterization by LC-MS, FTIR coupled with Job's plot and NMR titration studies confirm the formation of DBSA-Co complex with a binding constant of 4.61 × 10⁶ M^- 1. The chemo sensor exhibits a quantum yield of 0.082, highlighting its potential applicability in photochemical processes. Computation studies were used to further investigate the binding interactions with Co²⁺ ions. The practical utility of DBSA has been validated through successful analyses in varied aqueous matrices, including tap water, lake water and recycled water. Cytotoxicity assessment via MTT assays on SH-SY5Y cells confirms excellent biocompatibility of the probe. This work presents a significant advancement in the design of efficient molecular probes for environmental monitoring, offering a robust platform for the concurrent detection of transition-metal ions in aqueous systems.

Two novel Co(II)-based coordination polymers, [Co(HDNA)(bibp)(H₂O)]ₙ (CP1) and {[Co₃(DCPN)₂(4,4'-bibp)₃(H₂O)₄]}ₙ (CP2), were synthesized via hydrothermal reactions using H₃DCPN and different N-donor co-ligands. Structural analysis revealed that CP1 forms a 2D layered network, while CP2 adopts a 1D chain structure extended into a 3D supramolecular framework. Both CP1 and CP2 exhibited excellent fluorescence sensing abilities toward sulfamethoxazole (SMX), with strong enhancement responses. CP1 showed a linear Stern-Volmer relationship (R² = 0.9944) and a binding constant of 1.37 × 10⁴ M⁻¹, while CP2 gave R² = 0.9936 and K = 1.54 × 10⁴ M⁻¹. Both materials displayed high selectivity, anti-interference capacity, and good cycling stability, demonstrating their potential as reusable fluorescent sensors for SMX detection.

In this study, a novel fluorescent "turn-on" probe, (E)-N'-(2-(2-hydroxynaphthalen-1-yl) ethylidene)-2,5-diphenyl-2 H-1,2,3-triazole-4-carbohydrazide (G₄), was designed and synthesized, and fully characterized by various analytical techniques. Spectroscopic investigations revealed that G₄ exhibits excellent selectivity and sensitivity toward Al³⁺, with a 1:1 binding stoichiometry and a detection limit of 1.623 nM. Its advantages over existing probes include the lower detection limit and a distinct color reaction under UV light, which facilitates straightforward qualitative detection with lower cytotoxicity. The sensing mechanism was elucidated through density functional theory (DFT) and quantum chemical calculations. Then the practical utility of G₄ was demonstrated through recovery experiments in real water samples and its development into a portable test kit. Furthermore, cell experiments and zebrafish imaging confirmed its biocompatibility and applicability in biological systems with lower cytotoxicity. As a candidate drug that may be developed and utilized, the interactions of G₄ with two serum proteins (HSA and HIgG) were also investigated through spectrofluorometric and molecular docking analysis, revealing hydrogen bond or van der Waals forces as the main mode of action, suggesting potential for further biomedical applications. These results highlight G₄ as a highly sensitive, selective, and dual-functional fluorescent probe with significant potential for environmental monitoring and biological sensing.

The development of highly selective and sensitive fluorescent chemosensors is urgently needed to detect toxic aluminum ions (Al³⁺) ions in environmental and biological systems. This work presents the development of a novel Schiff-base fluorescent probe L, which was efficiently synthesized via a one-pot condensation reaction between 3,5-di-tert-butylsalicylaldehyde and 4,5-dimethyl-1,2-phenylenediamine. The molecular structure of the probe L was characterized using nuclear magnetic resonance spectroscopy (¹H/¹³CNMR) and infrared spectroscopy (FT-IR). Fluorescence spectroscopy studies have shown that probe L exhibits specific recognition of Al³⁺ in ethanol/PBS solutions. After adding Al³⁺, the fluorescence at 547 nm is significantly enhanced, displaying a bright green fluorescence under 365 nm ultraviolet light, and it is not interfered with by other metal ions such as Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe³⁺, Cu²⁺, and Zn²⁺. Job's plot and theoretical calculations confirm that probe L forms a 1:1 complex with Al³⁺, with a binding constant (K_a) of 2.64 × 10⁴ ± 44.67 M^- 1, and a detection limit (LOD) as low as 1.19 µM. This probe maintains stable recognition performance under a wide range of environmental conditions and has significant potential applications in environmental monitoring.