Journal of Cluster Science最新文献

Nowadays, the development of sustainable materials using chemical routes that are less harmful to the environment, adding social and economic viability to developed countries is a significant challenge. In this context, the present study extracted cellulose nanocrystals (CNC) based on two different chemical routes (H₂SO₄ and H₂SO₄/HCl) using a sub-wear out fiber from a natural resource in the semiarid Brazilian region with proposal of social and economically promoting this area and produce low-cost CNC. The two CNC (CNC H₂SO₄ and CNC H₂SO₄/HCl) were extensively characterized by spectroscopic analysis (FTIR, XPS, UV-Vis), X-ray diffraction, and morphological analysis (SEM, TEM). In addition, morphological analysis was performed after heat treatment to analyze the dependence on the thermodynamic kinetic in nucleation and growth of nanocrystals. The CNC biocompatibility was tested using a Resazurin assay. The results showed differences in morphologies, crystalline structures and chemical groups in the CNC depending on the chemical route. The sizes of CNC H₂SO₄ and H₂SO₄/HCl were 30 and 50 nm, respectively. The cytotoxicity studies were statistically similar showing biocompatibility (approximately 90%). Thus, these results indicated the potential to the possibility to improve social and economic conditions in the semiarid Brazilian region using a sub-wear-out waste as source producing a final product with aggregate value to the market.

In this work, we reported the simple one-step wet impregnation method of g-C₃N₄/MnO₂ nanocomposites aimed at improving the photocatalytic degradation efficiency of methylene blue dye. The synthesized catalysts underwent comprehensive characterization using various techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) to investigate their physicochemical properties. Their photocatalytic performance was evaluated by the degradation of methylene blue (MB) dye under visible light irradiation. Consequently, the MnO₂/g-C₃N₄ nanocomposite demonstrates superior photocatalytic degradation performance compared to both bare MnO₂ and g-C₃N₄. This enhancement is attributed to the improved efficiency of charge carrier separation and interfacial charge transfer within the nanocomposite structure. The degradation efficiency of MnO₂/g-C₃N₄ nanocomposite was found 89% of MB under visible light irradiation at 120 min. Meanwhile, the recyclability analysis demonstrated that the MnO₂/g-C₃N₄ nanocomposite can be recycled four times. Furthermore, the substance demonstrated positive antibacterial activity against Escherichia coli, and Staphylococcus aureus bacterial strains. These findings suggest that the MnO₂/g-C₃N₄ nanocomposite, with its dual roles as a photocatalyst and an antibacterial agent, has potential applications in environmental decontamination.

A facile hydro-solvothermal (Hyd/Solv) route is proposed for the synthesis of tin oxide nanostructures (left({text{S}text{n}text{O}}_{2} text{N}text{s}right)). Polycrystalline-tetragonal phases with different shape morphologies of ({text{S}text{n}text{O}}_{2}) and (text{S}text{n}text{O}) Ns were observed by X-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM). The energy gaps were tailored between 3.64 eV and 5.15 eV for the photodegradation of the methylene blue (MB) under sunlight exposure instead of an ultraviolet light source. Consequently, the photoefficiency of the nanostructured powder was comparable under 5 h of sunlight radiation. It thus may be concluded that the Hyd/Solv route confirms the strong dependence of photocatalysis on the synthesis technique mechanism.

Hexagonal molybdenum trioxide (h-MoO₃) was synthesized using egg white with MoO₃ precursor, which was further treated with nitric acid (HNO₃) by solution-based chemical precipitation technique for comparison without treatment. The XRD analysis confirms the formation of metastable phase with hexagonal crystal system for h-MoO₃ with and without HNO₃ treatment. Subsequently, the result indicate that the HNO₃ treated h-MoO₃ shows enhanced crystalline behavior compared to untreated h-MoO₃. Raman and FTIR analysis confirmed the formation of h-MoO₃ where the variation in intensity of the peaks were observed when comparing h-MoO₃ with and without HNO₃ treatment as well as due to the changes in the crystalline structure of the samples. The band gaps obtained from Tauc plot for the synthesized h-MoO₃ with and without HNO₃ treatment were 3.17 eV and 3.26 eV, respectively. Observations by HRSEM and HRTEM allowed confirming the formation of nanorod and nanoplate like structures for h-MoO₃ treated with and without HNO₃, respectively. In addition, the increased crystallinity of the HNO₃ treated h-MoO₃ was displayed higher anti-bacterial activity than untreated h-MoO₃ with zones of inhibition values of 14 ± 1 and 12 ± 1 mm against multi drug resistant (MDR) E. coli and K. pneumoniae, respectively. Subsequently, the quantitative analysis of HNO₃ treated h-MoO₃ demonstrated 94% and 96% inhibition against E. coli and K. pneumoniae, respectively, at 250 µg/mL concentration. Oxidative stress mediated membrane damages and surface morphology alterations were observed after exposure of HNO₃-treated h-MoO₃ (improved crystallinity) against E. coli and K. pneumoniae as suggested by confocal laser scanning electron microscopy and scanning electron microscopy. Furthermore, very minimal cytotoxicity to human alveolar epithelial cell line (A549) for HNO₃ treated h-MoO₃ was observed, suggesting that this material is benign. The present study indicates that the enhanced crystallinity of HNO₃ treated h-MoO₃ synthesized in the presence of egg white can be considered as a promising alternative drug target material to fight against MDR bacteria.

This study presents the biosynthesis of a novel polyvinylpyrrolidone (PVP)-modified Fe₂O₃/Fe₃O₄ nanocomposite (NC) using an olive leaf extract. The synthesized nanocomposites exhibit dual functionality, highlighting enhanced photocatalysis and antioxidant activity, offering promising applications in environmental remediation and therapeutics. The process involves meticulous biosynthesis and PVP-mediated surface modification, confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV–vis analysis. Both Fe₂O₃/Fe₃O₄ NC and Fe₂O₃/Fe₃O₄@PVP NC show spherical morphologies with average sizes of 21.7 nm and 30.1 nm, and optical bandgap energies of 1.8 eV and 1.34 eV, respectively. Photocatalytic activity assessments against amoxicillin antibiotic degradation under solar irradiation highlight the superior performance of PVP-modified nanocomposites, achieving an impressive 99% removal efficiency in 50 min compared to 84% for Fe₂O₃/Fe₃O₄ NC. Kinetic investigations reveal rate constants of 0.021 min^− 1 and 0.0025 min^− 1 for PVP-modified and unmodified nanocomposites, respectively, emphasizing the enhanced degradation rates. Optimization studies showcase the mass-dependent efficiency, with PVP-modified nanocomposites achieving a remarkable 91% removal rate of amoxicillin with a 7.5 mg catalyst. The recycling performance demonstrates sustained efficacy over five consecutive cycles, with only a slight decline from 99 to 97.5%. Moreover, the nanocomposites exhibited significant antioxidant activity, with Total Antioxidant Activity (TAC) values of 5.5 and 6.86 mg GAE/mg sample for Fe₂O₃/Fe₃O₄ NC and Fe₂O₃/Fe₃O₄@PVP NC, respectively. The environmentally synthesized PVP-modified Fe₂O₃/Fe₃O₄ NC showcases promising dual functionality, making them versatile candidates for efficient pollutant degradation and antioxidant applications in environmental and therapeutic domains.

Palladium nanoparticles (PdNPs) have emerged as promising metal nanoparticles in biomedical applications. In particular, green-synthesized PdNPs have gained significant attention due to their advantages of being simple, cost-effective, and low-toxic. This review summarizes the green synthesis of medicinal-oriented PdNPs using natural sources such as plants, mushrooms, algae, fungi, and biological molecules. Furthermore, this review discusses the potential biomedical applications of these green-synthesized PdNPs such as photothermal therapy, antibacterial/antitumor therapies, drug delivery, and imaging. It also identifies the current challenges and prospects for their use in these applications. Overall, this review demonstrates the promising potential of biogenic PdNPs for biomedical applications and provides valuable insights for future research in this field.

Graphical Abstract

Undoped, Fe, Sn doped and Fe/Sn co-doped copper oxides are prepared by precipitation synthesis. X-ray diffraction confirmed that the all synthesized powders show a monoclinic main CuO phase. The insertion of Fe or/and Sn within the CuO matrix moderately affects the preferential growth direction. Basically Fourier Transform Infrared (FTIR) confirmed about functional group and their vibrations in the CuO samples. The reflectance of the undoped sample is higher than that of the other samples. Compared to undoped CuO, the doped and co-doped NPs exhibit red-shifted gap energy. Indeed, the Fe-doped, and Sn-doped CuO NPs, exhibit a slight decrease of gap energy (1.47, 1.45 eV respectively) compared to the undoped CuO (1.49 eV), while the Fe/Sn co-doped sample has a lower gap energy of 1.06 eV.

Additionally, the antibacterial efficiencies of the all-synthesized samples are tested against Staphyloccus species. Doped and undoped CuO nanopowders show important antibacterial activity on tested bacteria with MICs values ranged between 0.039 to 1.25 mg/ml. Minimum Inhibitory Concentration value of 0.039 mg/ml was obtained with Fe-doped CuO NPs (CuO:Fe NPs) against S.aureus ATCC33591, whereas the highest MIC value of 1.25 mg/ml was obtained with CuO:Sn nanopowder against the strain S. epidermidis, which was the most resistant strain. Moreover, all CuO NPs, except CuO:Fe/Sn showed important anti-adhesive and antibacterial activities against S. epidermidis when used as pellets. This was confirmed either by cell counts using the determination of CFU/ml of bacterial suspension inside the hole, or by using fluorescence microscopy.

This paper presents an experimental study on preparation of tramadol hydrochloride (TrH) loaded nanoparticles, and stability determination in various infusion solutions. In this study, various nanoparticle preparation parameters based on w/o/w emulsification solvent evaporation method, including stabilizer type, stabilizer concentration, polymer concentration, homogenization speed and initial drug amount were systematically tested to verify their versatility for preparing nanoparticles. Initially both particle size and encapsulation efficiency of nanoparticles were changed significantly with the change in surfactant and polymer ratio (p<0.05). However, homogenization speed only changed particle size (average size 339.3±1.8 nm for 15000 rpm, 318.9±6.4 nm for 20000 rpm and 237.2±7.8 nm for 25000 rpm) (p<0.05) and initial drug concentration is only affected the encapsulation efficiency (34.2±0.7% for 4 mg/mL and 33.2±0.9 for 1.6 mg/mL) (p<0.05). Storage at room temperature for 3 months resulted in an increase in particle size and polydispersity index. Prepared nanoparticles showed the best stability after storage at – 20 °C for in 3 months. Finally, storage of nanoparticles in various infusion solutions resulted an undesirable changes for 6% Hydroxyethyl starch in 0.9% sodium chloride injection, 10% Dextran 40 and 4% Succinyl gelatin solutions. It was shown that an appropriate delivery of TrH loaded PLGA nanoparticles as infusion can be prepared only in water for injection, 20% Mannitol, 0.9% Sodium chloride and 5% Dextrose solutions.

Conventional biomineralization strategies are constructed using microparticles, suffering the inhibition of protease bio-availability and required rigorous bio-evaluation. The use of nanomineralization technology could apply control over the size, shape, and composition of the materials and provide a steadier maintenance environment for the bio-enzyme. In this study, stable and nanoscale copper phosphate (Cu₃(PO₄)₂) bio-nanomineralization materials were constructed to encapsulate free bio-enzyme. By optimizing the biomineralization process, Cu₃(PO₄)₂ was demonstrated to enable the facile coordination of various bio-enzymes (e.g., catalase or β-glucosidase) for efficient bio-enzyme transportation and maintaining the bio-enzyme activity in harsh condition. The current nanomineralization strategy could provide new ideas and methods for the development of biocatalysis, biosensing, biomedicine, and other related fields.