Luminescence最新文献

The electrocatalytic oxygen and hydrogen evolution reactions (OER and HER) are key processes used in energy storage and conversion. We have developed a highly efficient MnCo₂O₄ nanostructure anchored with functionalized carbon black (MnCo₂O₄/f-CB), which has been characterized by XRD, FT-IR, Raman spectra, FE-SEM, and HR-TEM analyses as robust bifunctional electrocatalysts for both HER and OER. At a characteristic 10 mA cm⁻² current density, the MnCo₂O₄/f-CB composite ECs exhibit low overpotentials of 330 mV for OER and 360 mV for HER, respectively. Furthermore, the MnCo₂O₄/f-CB composite ECs exhibit superior current density, the shortest Tafel slope, and admirable durable stability in OER and HER together. Due to the supported f-CB, the MnCo₂O₄ composite catalyst has more active sites, effective charge transfer, and longer durability. A high-efficiency dual electrocatalyst can be developed from these highly efficient and dual ECs, which are comparable to standard noble metal–based catalysts. The synergetic coupling effects of high-activity f-CB and MnCo₂O₄ composites with appropriate morphologies are critical factors for the enhanced catalytic performances of the MnCo₂O₄/f-CB composite.

The study aims to elucidate the pharmacological mechanism of Rauvolfia tetraphylla against breast cancer through a comprehensive, multi-faceted approach. This includes molecular docking, molecular dynamics, and experimental validation. Initial screening via ADME analysis and network pharmacology identified key compounds and potential targets. Protein–protein interaction (PPI) network analysis pinpointed Yes-associated protein-1 (YAP) as a crucial target. Molecular docking revealed that three compounds—ajmaline, reserpine, and serpentine—exhibited strong binding affinities with YAP, with scores of −6.5 to −6.7 kcal/mol. Molecular dynamics simulations were conducted to assess the stability of these interactions further. Experimental validation showed R. tetraphylla inhibited breast cancer cell proliferation, with an IC50 of 348.69 μg/mL, while demonstrating cytoprotective effects on Vero cells (IC50: 1056.23 μg/mL). Migration assays indicated an 88.5% reduction in cell migration, and increased ROS levels signaled elevated stress in cancer cells. Apoptosis was confirmed by AO/EtBr staining. In vivo validation in a DMBA-induced mouse model confirmed significant tumor growth inhibition, supported by changes in YAP expression and histopathological analysis. These findings highlight R. tetraphylla as a promising therapeutic candidate against breast cancer, offering insights into its mechanisms and potential for future drug development and clinical applications.

Heterogeneous photocatalysis has been widely explored as a promising solution for dye degradation due to its cost-effectiveness, ease of recovery, and use of green technology. Precisely, iron-doped cadmium sulfide (CdS) exhibits greater efficiency because of its higher charge separation, more electron transfer efficiency, and adsorption under visible region. In this study, two different ratios of iron-doped cadmium sulfide (Cd_(1-x)Fe_(x)S/GO) nanocomposites such as Cd_0.95Fe_0.05S/GO and Cd_0.90Fe_0.10S/GO were synthesized using the coprecipitation method and characterized with UV-Vis DRS, XRD, FT-IR, Raman, XPS, and HR-TEM. The nanocomposites have been employed to degrade the methyl orange under visible region and optimize the dopant ratio, amount of catalyst, and pH. From the results, it is observed that the composition with a high percentage of iron-doped CdS such as Cd_0.90Fe_0.10S/GO displayed better photocatalytic properties and improved the optimum ratio (0.9:0.1 for Cd:Fe). This may be attributed to the highest charge separation, increased number of defective sites, and enhanced visible-range adsorption owing to Fe doping. In addition to that, doping results reduce the band gap and size of the nanoparticles. It also increases recycling efficiency, reaching 93% after 10 cycles.

Wide color gamut display has become a new generation of display technology because of its good color saturation. However, the low quantum efficiency and wide half peak width of narrow-band green phosphors are still the main barriers in their development and application. This work addresses these challenges by using Mn²⁺ as the luminescent center and constructing efficient Eu²⁺ → Mn²⁺ energy transfer in Na₂MgAl₁₀O₁₇ (NMAO) matrix. The NMAO:0.15Eu²⁺, 0.30Mn²⁺ phosphor presents a single-band emission peaking at 513 nm with a full width at half maximum (FWHM) of only 33 nm under the excitation of 365 nm LED chip. In addition, under the excitation wavelength of 365 nm, the energy transfer efficiency reaches 74%. Compared with the NMAO:0.30Mn²⁺, the intensity of the NMAO:0.15Eu²⁺, 0.30Mn²⁺ increases by 5.5 times and the internal quantum efficiency is up to 61.82%. A white LED device with the CIE coordinates of (0.2871, 0.3472) and a color gamut area of 94% NTSC has been assembled successfully by combining 365 nm LED chips with NMAO:0.15Eu²⁺, 0.30Mn²⁺, BaMgAl₁₀O₁₇:Eu²⁺, and K₂SiF₆:Mn⁴⁺ as green, blue, and red component. This work enriches the relevant content of Mn²⁺-doped phosphors and provides a constructive insight into improving luminescent performance through energy transfer.

A curcumin-derived chemosensor 4,4′-((1E,3Z,5Z,6E)-3,5-bis((2hydroxyphenyl)imino) hepta-1,6-diene-1,7-diyl)bis(2-methoxyphenol) (HIBMP) was developed from curcumin and o-aminophenol using Schiff base condensation method. HIBMP selectively recognizes Cu (II) ion (Cu (II)) relative to other tested metal ions. Selective binding of Cu (II) ion turns off the fluorescent property of HIBMP and shows no interference with other metal ions. Moreover, the favourable binding of Cu (II) with HIBMP was noticed by a good linearity between the fluorescence intensity and concentration of Cu (II) with a range of 0–15.6 × 10⁻⁷ M, and the limit of detection was determined to be as low as 30.1 nM. Furthermore a 1:1 stoichiometry was identified from the results of Job's plot and HR-MS. Density functional theory (DFT) calculation results expressed that the intramolecular charge transfer (ICT) during chelation is responsible for quenching of fluorescence. Besides, the fluorescence life time measurement and ethylenediaminetetraacetic acid (EDTA) titration method revealed the stability and reversibility of the sensor. Practical use of the sensor was achieved through the quantitative analysis of spiked Cu (II) ion in real water samples with good recoveries, and biological experiments exposed that the sensor was less toxic and could be applied in fluorescence imaging of Cu (II) in living cells.

Clonazepam, a high-potency benzodiazepine widely prescribed for seizure and panic disorders, carries a risk of abuse and dependency. This study developed a sensitive and selective spectrofluorimetric method for determining 7-aminoclonazepam, the major metabolite of clonazepam, in human urine. A 2^6-2 factorial design was employed to screen the optimal conditions for derivatization with NBD-Cl as the fluorescent label, considering factors such as pH, reagent volumes, temperature, and reaction time. A significant model was attained (p < 0.0001) revealing alkaline pH (9), elevated temperature (80°C), and high reagent concentrations as crucial for maximizing fluorescence intensity. The method demonstrated excellent linearity from 10 to 500 ng/mL (R² = 0.9997), with limits of detection and quantitation of 3.3 and 10 ng/mL, respectively. Intra- and inter-day precision (% RSD) were less than 4%, and recoveries ranged from 97.59% to 106.12%. The method also showed no significant interference from endogenous compounds, pharmaceutical excipients, or the parent drug. Applicability of the method was validated in human subjects receiving clonazepam therapy; 7-aminoclonazepam was first detected after 12 h, peaked at 24 h (54.61 ± 9.870 ng/mL), and remained detectable up to 72 h post-dose, offering a simple, cost-effective spectrofluorimetric method for monitoring clonazepam metabolism in clinical and forensic settings.

This study presents a mild, one-pot synthetic approach for the synthesis of multicolor, water soluble, photo luminescent CdS and CdSe quantum dots (QDs). To achieve this goal, cyclic peptides containing cysteine residues are rationally designed and synthesized. Among the peptides tested, those containing two cysteine residues exhibit superior stabilizing properties, ensuring the solubility and long-term stability of the QDs in aqueous solutions for several months. The newly synthesized QDs exhibit unique excitation-dependent multicolor photoluminescence with a quantum yield of 20.55% and 45.50% for CdS and CdSe, respectively, providing versatility for imaging applications. Cellular uptake studies using HCT 116 cells reveal effective internalization of the QDs into both the cytoplasm and nucleus, highlighting their potential applications in bioimaging and drug delivery. This green synthesis approach underscores the crucial role of peptide chemistry in nanoparticle stabilization, paving the way for the development of functional nanomaterials tailored for specific uses in bioimaging and nanomedicine.

Mirabegron, a drug for treatment of overactive bladder, has low water solubility and bioavailability. Researchers used quality by design to develop and characterize second-generation lipid nanocarriers for mirabegron, aiming to provide spatially and temporally sustained drug release. Numerous analytical methodologies for assessing mirabegron in pharmaceutical and biological fluids use chemical solvents in the mobile phase, potentially impacting aquatic ecosystems and the environment. The issue was addressed with a microwave-assisted spectrofluorimetric technique, environmentally benign solvents, and a fluorescent probe known as 4-chloro-7-nitrobenzofuran. Researchers used screening design and response-surface methodology to minimize organic waste. The suggested technique satisfied ICH Q2 (R2) and M10 validation standards. This approach described the in vivo pharmacokinetics and in vitro drug release of mirabegron-loaded lipid nano-carriers. We anticipated the chemical reaction pathways that derivatized mirabegron with 4-chloro-7-nitrobenzofuran by the analysis of mass spectra. We assessed the proposed method's environmental effect and sustainability compared to current methods using the RGB model, an analytical greenness calculator, and green analytical process index software. The proposed mirabegron estimate method was user-friendly for analysts, cost-effective, sensitive, robust, and environmentally sustainable, adhering to sustainable analytical practices and reducing ecological consequences.

The fluorescence quenching behavior of rhodamine 6G (R6G) by graphene oxide (GO) under varying pH conditions was investigated. Utilizing steady-state fluorescence spectroscopy, single-photon counting, and ultrafast time-resolved absorption spectroscopy, we explored the quenching efficiency at pH values of 3, 7, and 11. Our findings reveal that GO effectively quenches R6G fluorescence across all tested pH levels, with the most significant quenching observed at pH 7. This quenching efficiency is attributed to optimal electrostatic interactions and efficient charge transfer between GO and R6G at neutral pH. At pH 3, the quenching efficiency is moderately reduced due to partial protonation of GO, which weakens electrostatic interactions but maintains hydrogen bonding. At pH 11, the quenching efficiency is lowest, likely due to increased electrostatic repulsion and reduced charge transfer resulting from deprotonation of GO. Ultrafast time-resolved absorption spectroscopy further confirmed the dynamic nature of the quenching process, showing distinct differences in relaxation kinetics across the pH spectrum. This study highlights the critical role of pH in modulating the quenching mechanisms of GO and R6G, providing valuable insights for the design of pH-sensitive fluorescence sensing systems.

Trimethylamine oxide (TMAO), a microbial metabolite commonly found in foods, has been attracting increasing attention as it is associated with the risk of several diseases. Simple and accurate analytical methods are crucial for TMAO study. In the present study, we proposed a chemical reaction-based fluorescence assay for TMAO detection using synthetic small molecular probes. After systematic screening and optimization, the sensitive and selective quantification of TMAO has been achieved based on a fluorescence probe P6 (3-iodopropanyl group modified resorufin). Excellent linearity (R² = 0.997) was found between 6.25 and 50 μM, and the limit of detection (LOD) was 0.20 μM. Using this method, TMAO levels in several marine fishes and shellfishes have been successfully analyzed. The probe-based assay offers a simple and useful way for TMAO determination. The design is inspired by the unique oxidation reaction between TMAO and halogen, which opens a new perspective in the development of more advanced analytical assays for TMAO in the future.