Search Results (2,339)

Background/Objectives: The present work deals with the sol–gel synthesis of hybrid materials based on a silica–polyvinylpyrrolidone (Si-PVP) system. Methods: The nanohybrids have been prepared using an acidic catalyst at ambient temperature. Ibuprofen (IBP) was used as a model substance in the obtained model drug systems, while tetraethyl orthosilicate (TEOS) was used as a silica precursor. Poly(vinylpyrrolidone) (PVP) and IBP were introduced into the reaction mixture as solutions in ethanol using two different approaches: (i) a direct introduction of a drug solution into the reaction mixture during sol–gel synthesis, and (ii) a solvent deposition technique. Results: XRD data provide evidence that IBP entrapped in the silica–PVP network is in an amorphous state. By SEM it was revealed that in the adsorbate, the IBP particles possess an average particle size of about 20 μm. Based on the obtained IR and UV-Vis spectral results, the existence of hydrogen bonding of IBF with silica and PVP could be suggested. Solid-state NMR analysis allowed the identification of the presence of both crystalline-like and amorphous phases in the hybrid material prepared by the sol–gel method, while it was demonstrated that in the adsorbate, the rigid crystalline dimeric structure of the drug has been preserved. Conclusions: The overall analysis of the structural characteristics of the two materials indicated that in the hybrid material obtained by the sol–gel method, the interactions between the amorphous drug, PVP, and the silica matrix are more pronounced as compared to the adsorbate. An improvement of the drug’s aqueous solubility as well of in vitro drug release profile (up to 8 h) was achieved, demonstrating the potential of the developed drug–silica–organic polymer nanohybrid as a promising drug delivery system. Full article

Barium strontium titanates (Ba_1−xSr_xTiO₃, BST) with varying barium-to-strontium ratios were synthesized by the solid-state route (SSR) as well as by the sol–gel process (SGP). In the case of the SSR, the strontium amount x was varied from 0.0 to 0.25 in 0.05 steps, due to the enhanced synthetic effort, and in the case of the SGP, x was set only to 0.05, 0.15, and 0.25. The resulting properties after synthesis, calcination, and sintering, like particle size distribution, specific surface area, particle morphology, and crystalline phase were characterized. The expected tetragonal phase, free from any remarkable impurity, was found in all cases, and irrespective of the selected synthesis method. Pressed pellets were used for the measurement of the temperature and frequency-dependent relative permittivity enabling the estimation of the Curie temperatures of all synthesized BSTs. Irrespective of the selected synthesis method, the obtained Curie temperature drops with increasing strontium content to almost identical values, e.g., in the case of x = 0.15, a Curie temperature range 95–105 °C was measured. Thin BST films could be deposited on different substrate materials applying electrophoretic deposition in a good and reliable quality according to the Hamaker equation. The properties of the BSTs obtained by the simpler solid-state route are almost identical to the ones yielded by the more complex sol–gel process. In future, this result allows for a possible wider usage of BST perovskites for ferroelectric and piezoelectric devices due to the easy synthetic access by the solid-state route. Full article

The chemical looping steam reforming of methane (CLSR) employing Fe-containing oxygen carriers can produce syngas and hydrogen simultaneously. However, Fe-based oxygen carriers exhibit low CH₄ activation ability and cyclic stability. In this work, oxygen carriers with fixed Fe content and different Fe/Ni ratios were synthesized by the sol–gel method to investigate the effects of Ni-Fe-Al interactions on CLSR performance. Ni-Fe-Al interactions promote the growth of the spinel structure and regulate both the catalytic sites and the available lattice oxygen, resulting in the CH₄ conversion and CO selectivity being maintained at 96–98% and above 98% for the most promising oxygen carrier, with an Fe₂O₃ content of 20 wt% and Fe/Ni molar ratio of 10. The surface, phase, and particle size were kept the same over 90 cycles, leading to high stability. During the CLSR cycles, conversion from Fe³⁺ to Fe²⁺/Fe⁰ occurs, along with transformation between Ni²⁺ in NiAl₂O₄ and Ni⁰. Overall, the results demonstrate the feasibility of using spinel containing earth-abundant elements in CLSR and the importance of cooperation between oxygen release and CH₄ activation. Full article

Humidity sensing elements based on sodium-doped titanium dioxide (Na-doped TiO₂) were prepared using a sol–gel method in the presence of cerium ions and sintered at 400 °C and 800 °C. Titanium (IV) n-butoxide and a saturated solution of diammonium hexanitratocerate in isobutanol served as starting materials. Sodium hydroxide and sodium tert-butoxide were used as inorganic and organometallic sodium sources, respectively. The influence of sodium additives on the properties of the humidity sensing elements was systematically investigated. The surface morphologies of the obtained layers were examined by scanning electron microscopy (SEM). Elemental mapping was conducted by energy-dispersive X-ray (EDX) spectroscopy, and structural characterization was performed using X-ray diffractometry (XRD). Electrical properties were studied for samples sintered at different temperatures over a relative humidity range of 15% to 95% at 20 Hz and 25 °C. Experimental results indicate that sodium doping enhances humidity sensitivity compared to undoped reference samples. Incorporation of sodium additives increases the resistance variation range of the sensing elements, reaching over five orders of magnitude for samples sintered at 400 °C and four orders of magnitude for those sintered at 800 °C. Full article

NASICON-type Li_1+XFe_XTi_2-X(PO₄)₃ (x = 0.1, 0.3, 0.4) solid electrolytes for all-solid-state Li-ion batteries were synthesized using a sol–gel method. This study investigated the impact of substituting Fe³⁺ (0.645 Å), a trivalent cation, for Ti⁴⁺ (0.605 Å) on ionic conductivity. Li_1+XFe_XTi_2-X(PO₄)₃ samples, subjected to various sintering temperatures, were characterized using TG-DTA, XRD with Rietveld refinement, XPS, FE-SEM, and AC impedance to evaluate composition, crystal structure, fracture-surface morphology, densification, and ionic conductivity. XRD analysis confirmed the formation of single-crystalline NASICON-type Li_1+XFe_XTi_2-X(PO₄)₃ at all sintering temperatures. However, impurities in the secondary phase emerged owing to the high sintering temperature above 1000 °C and increased Fe content. Sintered density increased with the densification of Li_1+XFe_XTi_2-X(PO₄)₃, as evidenced by FE-SEM observations of sharper edges of larger quasi-cubic grains at elevated sintering temperatures. At 1000 °C, with Fe content exceeding 0.4, grain coarsening resulted in additional grain boundaries and internal cracks, thereby reducing the sintered density. Li_1.3Fe_0.3Ti_1.7(PO₄)₃ sintered at 900 °C exhibited the highest density among the other conditions and achieved the maximum total ionic conductivity of 1.51 × 10⁻⁴ S/cm at room temperature, with the lowest activation energy for Li-ion transport at 0.37 eV. In contrast, Li_1.4Fe_0.4Ti_1.6(PO₄)₃ sintered at 1000 °C demonstrated reduced ionic conductivity owing to increased complex impedance associated with secondary phases and grain crack formation. Full article

Objective: Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), a variant of zirconia (ZrO₂), has attracted interest as a substitute for titanium in dental and orthopedic implants, valued for its biocompatibility and aesthetics that resemble natural teeth. However, its bioinert surface limits osseointegration, making surface modifications such as calcium phosphate (CaP) coatings highly relevant. Materials and methods: The review process adhered to the PRISMA guidelines. Electronic searches of PubMed, Scopus, Web of Science, Embase, and Cochrane Library (July 2025) identified studies evaluating CaP-coated zirconia implants. Eligible studies included in vitro, in vivo, and preclinical investigations with a control group. Data on coating type, deposition method, and biological outcomes were extracted and analyzed. Results: A total of 27 studies were analyzed, featuring different calcium phosphate (CaP) coatings including β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), octacalcium phosphate (OCP), and various composites. These coatings were applied using diverse techniques such as RF magnetron sputtering, sol–gel processing, biomimetic methods, and laser-based approaches. In multiple investigations, calcium phosphate coatings enhanced osteoblast attachment, proliferation, alkaline phosphatase (ALP) expression, and bone-to-implant contact (BIC) relative to unmodified zirconia surfaces. Multifunctional coatings incorporating growth factors, antibiotics, or nanoparticles showed additional benefits. Conclusion: CaP coatings enhance the bioactivity of zirconia implants and represent a promising strategy to overcome their inertness. Further standardized approaches and long-term studies are essential to verify their translational relevance. Full article

The adhesive bonding of high-pressure die-cast (HPDC) aluminum alloy AlSi10MnMg is extensively applied in the aerospace and automotive sectors. Surface pretreatment of HPDC aluminum prior to bonding is crucial for enhancing bonding strength and durability, as it regulates surface roughness, and chemical properties. Traditional multi-step surface treatments including chromic acid anodizing for HPDC AlSi10MnMg are hazardous, complex, and often fail to balance adhesive bonding durability and corrosion protection, limiting their industrial applicability. This study examined the impact of various chemical treatments on the adhesive bonding performance of an AlSi10MnMg aluminum alloy. The treated surfaces were bonded using a structural adhesive, and bonding performance was evaluated via wedge tests under pristine conditions and after accelerated aging. A scanning electron microscope (SEM) was used to study the surface morphology, chemical composition, and corrosion characteristics of the treated surfaces. Energy dispersive spectroscopy (EDS), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization measurements were employed. Excellent adhesion characteristics, dominated by the cohesive failure of the adhesive, were observed in H₂O₂-treated samples. The H₂O₂-treated samples exhibited the shortest initial crack length, indicating a superior baseline bonding quality, and showed minimal crack propagation (only slight extension) after aging under extreme environmental conditions (70 °C and 100% relative humidity for 4 weeks). Electrochemical measurements revealed that the SG200-treated sample achieved the lowest corrosion current density (0.25 ± 0.03 μA/cm²) with an excellent corrosion resistance, while sol–gel-treated samples generally suffered from a poor adhesion, with interfacial failure. This study proposes a simplified, single-step chemical treatment using an H₂O₂ solution that effectively achieves both a strong adhesive bonding and an excellent corrosion resistance, without the drawbacks of conventional methods. It offers a viable alternative to conventional multi-step hazardous surface treatments. Full article

The alarming rise in foodborne illnesses, particularly those associated with microbial contamination in meat products, presents a serious challenge to global food safety. Among these microbial threats, Pseudomonas aeruginosa (P. aeruginosa) poses a critical threat due to its biofilm-forming capability and prevalence in contaminated beef, highlighting its effective real-time detection. Herein, we report the fabrication of a novel electrochemical aptasensor based on multimetal perovskite (FeCoCuNiO) doped with urea-derived graphitic carbon nitride (g-C₃N₄), synthesized via a sol–gel combustion method. The FeCoCuNiO-g-C₃N₄ nanocomposite was then coated onto a graphitic pencil electrode and functionalized with a DNA-based aptamer specific towards P. aeruginosa. The resulting aptasensor exhibited a low detection limit of 3.03 CFU mL⁻¹ with high selectivity and sensitivity, and was successfully applied to real-time detection of P. aeruginosa in food samples. To the best of our knowledge, this work presents the first FeCoCuNiO-g-C₃N₄-based aptasensor for bacterial detection, offering a promising platform for food safety assurance and public health protection. Full article

In this work, we report optical and photoelectrochemical properties of BiVO₄ synthesized by microwave, sonochemical, sol–gel, and direct deposition on conductive substrate methods. Structural and morphological characterization using XRD, SEM, and AFM confirmed the presence of both monoclinic and tetragonal phases, with variations in particle size and surface roughness. UV-Vis spectroscopy revealed band gaps in the range of 2.38–2.51 eV. Photoelectrochemical performance was evaluated through measurements of photocurrents under varying illumination wavelengths and applied potentials. BiVO₄ as a thin film exhibited the highest photocurrent intensity due to its superior semiconductor–substrate contact. In contrast, BiVO₄ samples obtained as a powder showed significantly lower photocurrents but demonstrated the photocurrent switching effects, attributed to the presence of surface trap states and oxygen vacancies. The obtained results highlight the importance of synthesis strategy in tailoring BiVO₄ properties for use as a photoelectrochemical cell and suggest potential applications in molecular electronics, such as logic gates and memory devices. Full article

YVO₄ based phosphors have aroused extensive interest in the field of optoelectronics due to their good chemical stability and unique luminescence properties. However, commercialization of YVO₄ phosphors requires high luminescence intensity, enhanced conversion efficiency, and a wide excitation spectrum. In this work, Eu³⁺, Ba²⁺, Bi³⁺ co-doped YVO₄ was prepared by the sol–gel method. The XRD of YVO₄: 5%Eu³⁺, 5%Ba²⁺, 0.5%Bi³⁺ phosphor analysis confirms the pure tetragonal phase, with a fairly large size of approximately 100 nm for the optimal composition. And the SEM and TEM revealed well-dispersed spherical nanoparticles with sizes of 100–120 nm. The introduction of Ba²⁺ ions enhanced the luminescence intensity, while the incorporation of Bi³⁺ ions improved the excitation width of the phosphor. The resulting YVO₄: 5%Eu³⁺, 5%Ba²⁺, 0.5%Bi³⁺ phosphor exhibited a 1.39-times broader excitation bandwidth and a 2.72-times greater luminescence intensity at 618 nm compared to the benchmark YVO₄: 5% Eu³⁺ sample. Additionally, the transmittance of the films in the 350 nm to 800 nm region exceeded 85%. The YVO₄: 5%Eu³⁺, 5%Ba²⁺, 0.5%Bi³⁺ film effectively absorbed ultraviolet light and converted it to red emission, enabling potential applications in solar cell window layers, dye-sensitized cell luminescence layers, and solar cell packaging glass. Full article

We report Al/ZnO/Al optoelectronic synaptic devices fabricated on c-plane and m-plane sapphire substrates using a sol–gel process. The devices exhibit essential synaptic behaviors such as excitatory postsynaptic current modulation, paired-pulse facilitation, and long-term learning–forgetting dynamics described by Wickelgren’s power law. Comparative analysis reveals that substrate orientation strongly influences memory performance: devices on m-plane consistently show higher EPSCs, slower decay rates, and superior retention compared to c-plane counterparts. These characteristics are attributed to crystallographic effects that enhance carrier trapping and persistent photoconductivity. To demonstrate their practical applicability, 3 × 3-pixel arrays of adjacent devices were constructed, where a “T”-shaped optical pattern was successfully encoded, learned, and retained across repeated stimulation cycles. These results highlight the critical role of substrate orientation in tailoring synaptic plasticity and memory retention, offering promising prospects for ZnO-based optoelectronic synaptic arrays in in-sensor neuromorphic computing and artificial visual memory systems. Full article

Nickel–zinc batteries are promising candidates for safe, cost-effective, and high-power energy storage. However, the poor cycling stability of zinc anodes, mainly caused by dendrite growth and dissolution, remains a major challenge for their practical application. Herein, carbon-coated nano-ZnO (ZnO@C) composites were synthesized via a sol–gel method using polyvinyl alcohol (PVA) and zinc acetate as precursors. By systematically tuning the carbon content, the ZnO@C-6 sample with a carbon-to-ZnO mass ratio of 1:6 exhibited the best structural and electrochemical performance. Characterization confirmed a uniform amorphous carbon layer that enhanced conductivity and inhibited ZnO dissolution. Electrochemical tests demonstrated that ZnO@C-6 exhibited high reversible capacity (500 mAh g⁻¹ at 12 C after 1000 cycles), coulombic efficiency (>80%), and superior rate capability up to 30 C. Post-cycling SEM confirmed that the carbon coating effectively inhibits dendrite formation and preserves electrode morphology. These findings highlight the critical role of carbon coatings in stabilizing ZnO-based anodes and offer a viable pathway toward high-performance Ni-Zn batteries. Full article

Background: Current Alzheimer’s disease (AD) treatments primarily focus on symptom management and offer limited potential to arrest disease progression. To address this limitation, we developed baicalin–myricetin (BM) functionalized selenium nanoparticles (SeNPs), termed BMSe@BSA, aimed at multi-targeted neuroprotection. Materials and Methods: BMSe@BSA nanoparticles were synthesized via a gel–sol technique using bovine serum albumin (BSA), ascorbic acid, selenous acid, and BM. Interactions among BSA, BM, and SeNPs were characterized by microscopy and spectrometry. Cytotoxicity was assessed on RAW 264.7 and PC12 cells to determine biocompatibility. Neuroinflammation and cognitive function were evaluated in C57BL6/J mice challenged with Aβ1-42. Recognition memory was tested through open-field exploration, novel object recognition (NOR), and T-maze assays. Inflammatory markers (IL-1β and TNF-α) and microglial changes in the cerebral cortex were quantified, while amyloid fibril morphology was assessed using atomic force microscopy (AFM). Results: Spectroscopic analysis verified successful BM functionalization. Transmission electron microscopy revealed a spherical morphology with an average particle size of 90.57 nm, zeta potential of 27.2 mV, and a polydispersity index (PDI) of 0.270. BM entrapment efficiency reached approximately 90%. Cytotoxicity assays confirmed the nanoparticles’ safety, with no toxicity observed at concentrations up to 400 µg/mL after 4 h of incubation. BMSe@BSA effectively inhibited amyloid fibril formation, downregulated pro-inflammatory cytokine expression, preserved neuronal integrity, and significantly enhanced cognitive performance in AD mouse models. Conclusion: BMSe@BSA appear as a potential nanotherapeutic approach for targeted brain delivery and multi-pathway intervention in Alzheimer’s disease. Full article

Triclosan (TCS), a persistent antimicrobial and endocrine-disrupting compound, is commonly found in surface and groundwater due to incomplete removal by conventional wastewater treatment. This study evaluated its fate in authentic rainwater runoff collected from a state road using rubber tiles made from recycled tires that were either uncoated (RRT) or coated with TiO₂ via the sol–gel method (SGT). Pollutants were analyzed by a high-resolution liquid chromatography–quadrupole time-of-flight mass spectrometry system (LC/MS QTOF) before and after treatment in a flat-plate cascade reactor under UV-A irradiation. After 120 min SGT achieved >50% TCS removal, while RRT achieved ~44%. Further analysis identified degradation products (chlorocatechole, quinone, and transient dioxin-like species). ECOSAR predictions indicated moderate to high toxicity for some degradation products, but their transient and low-abundance detection suggests that photocatalysis suppresses accumulation, ultimately yielding less harmful products such as benzoic acid. These findings highlight the dual role of TiO₂-coated rubber tiles: improving material durability while enabling photocatalytic degradation. Full article

Neurodegenerative disorders (NDs), including Alzheimer’s disease and Parkinson’s disease, pose a significant global health challenge characterized by progressive neuronal loss and limited therapeutic options. Early diagnosis remains a considerable hurdle due to the absence of reliable biomarkers and the restrictive nature of the blood–brain barrier (BBB), which complicates effective drug delivery. Magnetic nanoparticles (MNPs), particularly those based on iron oxide, have emerged as promising tools for both diagnostic and therapeutic applications in NDs, thanks to their superparamagnetism, biocompatibility, and customizable surfaces. This review examines various synthesis strategies for MNPs, encompassing physical methods (such as lithography, ball milling, and laser ablation) and chemical approaches (co-precipitation, thermal decomposition, hydrothermal synthesis, sol–gel processes, and polyacrylamide gel techniques), while highlighting how these techniques influence particle properties. This review also explores recent advancements in surface functionalization using polymers and coatings to enhance circulation time in the bloodstream and improve BBB penetration for targeted delivery. Furthermore, it emphasizes both in vitro and in vivo applications, showcasing MNPs’ effectiveness in enhancing imaging sensitivity and enabling targeted drug and gene delivery. By linking synthesis methods, functionalization techniques, and biomedical outcomes, this review illustrates the transformative potential of MNPs as next-generation theranostic agents in precision medicine for neurodegenerative diseases. Full article