Search Results (4,747)

Background: Silver fluoride medicaments effectively arrest caries progression but cause permanent staining. Nanoparticles are increasingly utilised in paediatric dentistry due to their antimicrobial properties. Aim: This study reports the synthesis and characterisation of silver and selenium nanoparticles stabilised with natural agents. Methods: Six silver and selenium nanoparticles were chemically synthesised and stabilised using biocompatible eco-friendly capping agents, including casein, bovine serum albumin, chitosan, citrate, and tannic acid. Characterisation was performed using Tyndall scattering, UV-Vis spectroscopy, transmission electron microscopy, and ICP-OES. Results: The synthesised particles were spherical in shape, ranging in size from 2.5 to 24 nm for silver and 35 to 43 nm for selenium. Elemental analysis confirmed the absence of heavy metals. Conclusions: These findings highlight the successful synthesis of capped silver and selenium nanoparticles. The observed characteristics suggest potential relevance for future antimicrobial applications in paediatric dentistry. Full article

This research prepared and characterised novel mixed coordination complexes derived from escitalopram with eugenol and curcumin to form (L₁) and (L₂), respectively. The complexes were prepared via Williamson ether synthesis and analysed by FTIR, UV–Vis, ¹H-NMR spectroscopy, elemental analysis, molar conductivity, and magnetic susceptibility. The results confirmed their octahedral geometries. Magnetic investigation reported high-spin configurations for Mn(II), Co(II), and Ni(II) complexes, whereas Cu(II) exhibited a distorted octahedral arrangement with characteristic d–d transitions. In addition, the calculation of Density functional theory (DFT) provided more insight into the detailed structural and electronic properties of the new ligand and its complexes. Antimicrobial compounds were evaluated against Escherichia coli, Staphylococcus aureus, and Candida albicans through the agar well diffusion method. The reported results revealed that Cobalt complexes showed antimicrobial activity followed by Copper (Cu), Nickel (Ni) and Manganese(Mn) complexes, respectively, due to an increase in Co-lipophilicity, which leads to improved diffusion through microbial cell membranes. The research findings confirmed that escitalopram-based mixed ligands coordinate with transition metals and could have significant biological applications. Full article

A new copper(II) complex was synthesized using chromone-2-carboxylic acid as the main ligand, and coordinated pyridine molecules. The complex was successfully crystallized and structurally characterized by single crystal X-ray diffraction. This revealed a mononuclear structure with a distorted square pyramidal geometry around the central Cu(II) ion. The coordination sphere comprises oxygen atoms from the chromone moiety and nitrogen atoms from pyridine, resulting in a five-coordinate complex. A comprehensive physicochemical characterization was performed using Fourier transform infrared spectroscopy (FT-IR), UV–Vis spectroscopy, elemental (C, H, N), electrochemical (CV) and thermal analysis (TGA/DSC) to confirm the coordination environment and thermal stability of the compound. The complex exhibits distinct spectroscopic features indicative of ligand–metal charge transfer and d–d transitions typical of Cu(II) species. In addition, the synthesized complex was subjected to antimicrobial screening against Gram-positive and Gram-negative bacteria. The compound showed promising antibacterial activity, particularly against Escherichia coli, indicating its potential as a bioactive coordination compound. These results contribute to the growing body of research on metal-based chromone derivatives and emphasize the importance of copper complexes for the development of new antibacterial agents with defined crystal structures. Full article

The photocatalytic efficiency of TiO₂ was significantly enhanced by coupling with WO₃ to form a TiO₂/WO₃ heterostructure, designed to operate effectively under UV-LED irradiation. The nanocomposites were synthesized via a hydrothermal route, and their activity was evaluated through the degradation of the pharmaceutical pollutant venlafaxine. Contaminants are rarely addressed in photocatalytic studies. Unlike a simple physical mixture of commercial TiO₂ and WO₃ powders, the hydrothermally synthesized TiO₂/WO₃ photocatalyst exhibited superior efficiency, attributable to its nanoscale dimensions achieved via the hydrothermal route, which promoted improved charge carrier separation, enhanced surface homogeneity, and the formation of an effective heterojunction interface. An optimization study varying the WO₃ content (5, 10, 20, and 30 wt.%) within the TiO₂ revealed that the 10 wt.% WO₃ composition achieved the highest performance, with ~52% venlafaxine degradation within 60 min. SEM, TEM, FTIR, Raman spectroscopy, XRD, and UV-Vis DRS revealed the successful incorporation of WO3 into the TiO₂ matrix, confirming phase purity and composition-dependent structural evolution of the nanocomposite, and evidencing extended light absorption and superior charge-transfer properties. Importantly, the optimized photocatalyst thin film retained excellent stability and reusability, maintaining high degradation efficiency over three consecutive cycles with negligible activity loss, which avoids slurry separation. These findings establish hydrothermally synthesized TiO₂/10%WO₃ thin film heterostructures as effective and sustainable photocatalytic platforms for the removal of pharmaceutical pollutants in wastewater under UV-LED irradiation. Full article

In this study, Cu(II) complexes containing the bidentate ligand N,N-dimethylethylendiamine (dmen), i.e., [Cu^II(dmen)₂(CH₃COO)₂], [Cu^II(dmen)₂(NO₃)₂], and [Cu^II(dmen)₂Cl₂], were developed to explore molecular catalysis for the oxygen reduction reaction (ORR). Cyclic voltammetry and UV–vis spectroelectrochemical and electrochemical impedance spectroscopy experiments were performed in the absence and presence of oxygen. The UV–vis spectroscopy results suggested that the aforementioned Cu(II) complexes present an octahedral geometry in the solid state; meanwhile, they show a square pyramidal geometry in an aqueous solution. It is proposed that the chemical species [Cu^I(dmen)₂H₂O]⁺ reacts with O₂, exhibiting an outer-sphere electron transfer mechanism. The same UV–vis spectroelectrochemical response obtained with and without O₂ indicated a direct electron transfer from Cu(II) to Cu(I), with the regeneration of catalyst and the absence of other intermediate species. Among the reported compounds, [Cu(dmen)₂(NO₃)₂] exhibited the highest catalytic rate (TOF = 1.3 × 10⁴ s⁻¹). The impedance spectroscopy results showed that the resistance charge transfer (R_ct) of the redox pair Cu^II|Cu^I decreased in the presence of O₂ from 36.391 kΩ to 5.54 kΩ. For a better understanding of the effect of aliphatic amines on the ORR, a comparison with the complex [Cu(1,10-phen)₂NO₃]NO₃ is also presented. Full article

We report the study of seven commercially available rosehip oils (Rosa canina L.) using GC-MS, colorimetry (CIELab), UV-VIS, FTIR, and 3D EEM fluorescence spectroscopy, including using a smartphone spectrometer. GC-MS revealed two groups of oil samples with different chemical constituents: ω-6-dominant with 45–51% α-linolenic acid (samples S1, S2, and S5–S7) and ω-3-dominant with 47–49% α-linolenic, 7.3–19.1% oleic, 1.9–2.8% palmitic, 1.0–1.8% stearic, and 0.1–0.72% arachidic acid (S3, S4). In S1 PUFA content was found to be ~75% with ω-6/ω-3 ≈ 2:1. Favorable lipid indices of AI 0.0197–0.0302, TI 0.0208–0.0304, and h/H 33.0–50.6 were observed. The highest h/H (50.55) was observed in S5 and the lowest TI (0.0208) in S3. FTIR showed characteristic lines at ~3021, 2929/2853, 1749, and ~1370 cm⁻¹, and PCA yielded 60–80% variation and separated S1 from the rest of the samples, while the clusters grouped S5 and S6. The smartphone spectrometer also reproduced the individual differences in sample volumes ≤ 1 µL under 355–395 nm UV excitation. The non-destructive optical markers reflect the fatty acid profile and allow fast low-cost identification and quality control. An integrated control method including routine optical screening, periodic CG-MS verification, and chemometric models to trace oxidation and counterfeiting is suggested. Full article

Background: Hepatocellular carcinoma is associated with high mortality and increasing incidence. Sorafenib, a cornerstone of therapy for advanced hepatocellular carcinoma, presents certain disadvantages, including low bioavailability and poor water solubility. This work describes a new strategy for sorafenib-targeted delivery aimed at improving treatment efficiency and reducing side effects. Methods: Magnetic nanoparticles coated with azelaic acid were modified with aptamer molecules that specifically recognize human liver cancer cell line HepG2, ensuring specificity for the tumor tissue. The nanoparticles were further loaded with sorafenib. The obtained drug delivery system was extensively characterized using UV-Vis spectrophotometry, transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Results: The drug delivery system demonstrated a higher release of sorafenib at acidic pH compared to pH 7.4. The cell internalization of the bare and aptamer-modified magnetic nanoparticles was assessed in HepG2 and human normal foreskin fibroblasts BJ cell lines, demonstrating that the aptamer significantly enhances internalization in tumor cells, while having no impact on healthy cells. Conclusions: The sorafenib-modified nanoparticles exhibited excellent cytocompatibility with BJ cells across all tested concentrations, while showing cytotoxicity towards HepG2 cells at higher concentrations, confirming the selectivity of the system. Full article

Zinc oxide (ZnO) is a wide bandgap semiconductor with optoelectronic and photocatalytic properties, which depend on its optical, structural, and morphological characteristics. In this study, we synthesized ZnO thin films by chemical bath deposition (CBD) and then thermally annealed them at 400 °C and 600 °C to evaluate the effect of thermal treatments. We characterized their structural, optical, morphological, and chemical properties using X-ray diffraction (XRD), UV–Vis spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The optical bandgap values were 3.20 eV for the as-grown thin films, and 3.23 eV and 3.21 eV after annealing at 400 °C and 600 °C, respectively. SEM micrographs revealed a change from elongated agglomerates in the as-grown thin films to uniform flower-like structures after annealing at 600 °C. XPS analysis confirmed ZnO formation in all samples, and we detected residual precursor species only in the as-grown thin films, which were completely removed by annealing at 600 °C. These results demonstrate that the CBD synthesis of ZnO can tune its optical and morphological properties through thermal annealing, making it suitable for optoelectronic, sensing, and photocatalytic applications. Full article

Cytisine, a naturally occurring alkaloid and partial agonist of nicotinic acetylcholine receptors (nAChRs), has long been used as a smoking cessation aid and serves as the pharmacophore for varenicline. Recent research has expanded its therapeutic scope to neurodegenerative and neurological disorders, motivating the development of new cytisine derivatives. Among these, N-propargylcytisine combines the biological activity of the parent compound with the synthetic versatility of the terminal alkyne group. Herein, we report the synthesis and characterization of N-propargylcytisine, and its symmetrical dimer linked through 1,3-diyne moiety obtained via a copper-mediated Glaser–Hay oxidative coupling. The products were analyzed by NMR, FT-IR, and mass spectrometry, confirming the introduction of the propargyl moiety and the formation of the diyne bridge. Solvatochromic study of both compounds were performed using UV-VIS absorption spectroscopy in solvents of varying polarity, including protic solvents capable of hydrogen bonding. The 1,3-diyne motif, commonly found in bioactive natural products, endows the resulting dimer with potential for further derivatization and biological evaluation. This study demonstrates the utility of the Glaser–Hay reaction in the functionalization of alkaloid scaffolds and highlights the prospects of N-propargylcytisine derivatives in drug discovery targeting the central nervous system. Full article

Gold nanoparticles (AuNPs) are attracting more and more attention in life sciences, especially due to their versatile physicochemical properties whereby their colloidal stability in water and organic solvents is crucial. In this study, a systematic comparison of different polymers, synthesis methods and solvents was carried out. The AuNPs were synthesized using the ligand exchange reaction/postsynthetic addition reaction (PAR) and the one-pot synthesis with the polymers poly(vinyl alcohol) (PVA), poly(ethylene glycol) (PEG), poly(vinylpyrrolidone) (PVP) and poly(acrylic acid) (PAA), each with different molar weight averages. Analysis of the AuNP@Polymer conjugates by transmission electron microscopy (TEM) finds essentially unchanged gold nanoparticle core sizes of 11–18 or 11–19 nm in water and ethanol, respectively. The hydrodynamic diameter from dynamic light scattering (DLS) lies largely in the range from 20 to 70 nm and ultraviolet-visible spectroscopy (UV-Vis) showed gold plasmon resonance band maxima between 517 and 531 nm over both synthesis methods and solvents for most samples. The polymer PVA showed the best colloidal stability in both synthesis methods, both in water and after transfer to ethanol. An increased instability in ethanol could only be noted for the PEG coated samples. For the polymers PVP and PAA, the stability depended more specifically on the combination of synthesis method, polymer molecular weight and solvent. Full article

A key obstacle to the efficacy of cancer drugs is the safe delivery of the drugs to the target site of the disease. Recent advances in nanomedicine have introduced smart hydrogel nanoparticles as promising, efficient, secure, and stimulus-responsive drug carriers. Herein, a bio-safe pH-sensitive nanohydrogel (NG) made of polyaminoethyl methacrylamide (AEMA)-grafted dextran was used as a carrier for liver-targeted doxorubicin (DOX) delivery. Lactobionate (SL) residue was conjugated to the prepared NG as a targeting agent, and DOX was also conjugated via Schiff base linkage. The synthesized structure was analyzed using ¹HNMR, FT-IR, and size exclusion chromatography. DOX release was confirmed through UV-Vis spectroscopy. A pH-responsive manner in the DOX release profile was observed in a simulated medium with pH changes. In vitro toxicity assessment was performed in HepG2 and L929 cell lines, which have demonstrated the biosafety of the prepared hydrogel and its high effectiveness as an anticancer drug delivery system. Full article

In this work, the removal of Cu(II) ions from an aqueous effluent was studied using an Mg/Fe layered double hydroxide (LDH) as the adsorbent. The material was synthesized and characterized before and after the adsorption process to identify structural and morphological changes induced by copper uptake. Techniques such as X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), ultraviolet-visible spectroscopy (UV-Vis), Raman spectroscopy, and nitrogen physisorption (BET) were employed to confirm the interaction between the metal ions and the LDH surface. The LDH-Mg/Fe exhibited a high maximum adsorption capacity of 526 mg/g, and the adsorption kinetics followed a pseudo-second-order model, achieving over 90% removal of Cu(II) within 2.5 h. The Cu(II)-loaded material was subsequently evaluated as a sustainable catalyst in two applications: (i) an organic synthesis via “click” chemistry, reaching yields of up to 85%, and (ii) the decoloration of Congo Red via a Fenton-like process, achieving a decoloration efficiency of at least 84%. These dual uses demonstrate the potential of Cu(II)-loaded LDH as a cost-effective and environmentally friendly approach to simultaneous pollutant removal and catalytic valorization. Full article

Although spontaneous or complexation-induced reductions of Cu^II to Cu^I have occasionally been observed, controlling these processes remains a challenge. Herein, we report the synthesis of Cu^I complexes via the complexation-induced reduction of Cu^II complexes with pyridine-containing N₄ Schiff-base ligand L incorporating a biphenyl unit (L = N,N’-([1,1′-biphenyl]-2,2′-diyl)bis(1-(6-methylpyridin-2-yl)methanimine)). Such a reduction has not yet been observed in previously reported Cu^II complexes with pyridine-containing N₄ Schiff-base ligands, strongly suggesting that the torsional distortion of the ligand framework induced by the biphenyl moiety effectively promotes the complexation-induced reduction of Cu^II to Cu^I. The Cu^I complexes were thoroughly characterized by ¹H NMR spectroscopy, UV–vis–NIR spectroscopy, and single-crystal X-ray diffraction analyses. The [Cu^I(L)]⁺ complex undergoes a reversible redox process with its oxidized species, which was identified as a Cu^II complex based on spectroelectrochemical measurements and theoretical calculations. Full article

Oxygen-deficient tungsten oxide W₁₈O₄₉ was synthesized through lattice oxygen escaping at high temperature in N₂ atmosphere. The temperature and inert atmosphere were critical conditions to initiate the lattice oxygen escaping to obtain W₁₈O₄₉. The large amount of oxygen vacancies supports its performance in photothermal conversion. The synthesized tungsten oxides were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible absorption spectroscopy (UV-Vis). The composite gel was fabricated by the insertion of oxygen-deficient tungsten oxide into PVA-based gel, which was cross-linked by glutaraldehyde. The PVA-based gel ensures a matched water supply speed with that of the evaporation rate due to its hydrophilic nature. The result of the solar steam generation shows that the W₁₈O₄₉-PVA gel (steam generation rate 2.65 kg m⁻² h⁻¹) was faster than that of the pure PVA gel. Full article

A novel heterobimetallic ruthenium(II)–gold(I) complex featuring a bridging bis(diphenylphosphino)butane (dppb) ligand was prepared and fully characterized. Single-crystal X-ray diffraction revealed a piano-stool geometry around Ru(II) with η⁶-cymene, two chlorido ligands, and one phosphorus atom from dppb, while the Au(I) center adopts a linear P–Au–Cl coordination. Structural integrity in the solution was confirmed by 1D and 2D NMR spectroscopy, while solution behavior was further monitored by variable solvent ³¹P NMR and UV/Vis spectroscopy, indicating that the organometallic Ru–arene core remains intact, whereas the chlorido ligands coordinated to Ru exhibit partial lability. Complementary characterization included elemental analysis, FTIR, and UV/Vis spectroscopy. Spectrofluorimetric and FRET analyses showed that Au(dppb), Ru(dppb), and the heterobimetallic AuRu complex bind to BSA with apparent constants of 1.41 × 10⁵, 5.12 × 10², and 2.66 × 10⁴ M⁻¹, respectively, following a static quenching mechanism. In vivo biological evaluation in Wistar rats revealed no significant hepatotoxicity or nephrotoxicity, with only mild and reversible histological alterations and preserved hepatocyte nuclear morphology. Hematological analysis indicated a statistically significant reduction in leukocyte populations, suggesting immunomodulatory potential, while elevated serum glucose levels point to possible endocrine or metabolic activity. These findings highlight compound structural stability and intriguing bioactivity profile, making it a promising platform for further organometallic drug development and testing. Full article