Ultraviolet-visible Spectroscopy Research Articles

Green Synthesis, Chemical Characterization, Antioxidant, Cytotoxicity and Anticancer Effects of Vanadium Nanoparticles

Silybum marianum is a plant with many remedial properties and may help prevent the cancer spread. Studies in this field show that this plant can reduce the growth of cancer cells. Probably, Silybum marianum will improve the effectiveness of chemotherapy. Also, the side effects of the recent treatments may be reduced by using this plant. The Food and Drug Administration has not confirmed Silybum marianum for the cancer treatment, but it may be effective in the treatment of these cancers: prostate, breast, cervical, blood, small intestine, and skin. Researching formulation of metallic nanoparticles by medicinal plants is the research priority of all countries. In the current experiment, we synthesize the vanadium nanoparticles by the watery extract of the Silybum marianum aerial parts. The characterization was conducted by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, fourier transform infrared, energy-dispersive X-ray spectroscopy, and ultraviolet–visible spectroscopy. The DPPH inhibition efficacy was assessed by the DPPH examination, while the MTT assay was used to evaluate anti-cervical cancer (against LM-MEL-41, HT-3, Ca Ski, DoTc2 4510, SiHa, and C-33 A cells) and cytotoxicity efficacy of vanadium NPs. In XRD, the signals at 2 theta values of 25.13, 27.77, 44.94, 49.52, 66.28, and 70.57 belong to the planes of (202), (103), (401), (205), (406), and (125) respectively. Based on the findings of FE-SEM, the NPs are formed with the morphology of spherical with an aggregation. In FT-IR, the peaks at 416 and 551 cm−1 can be assigned to V–O–V and V–O bonds. The EDS analysis confirms the vanadium presence by the signals at 5.45 (VKβ), 4.98 (VKα), and 0.53 (VLα). The other signals below 0.5 KeV verify the appearance of carbon and oxygen in the green synthetic vanadium nanoparticles. The V nanoparticles IC50 was 126, 157, 165, 125, 132, and 197 μg/mL against LM-MEL-41, HT-3, DoTc2 4510, C-33 A, SiHa, and Ca Ski cervical cancer cells, respectively.

Structural and optical properties of mesoporous akermanite derived from industrial waste for multifunctional applications

The present study focuses on the synthesis of akermanite by chemical free hydrothermal route using two major industrial waste ground granulated blast furnace slag (GGBS) and coal fly ash (FA) as the initial precursors. Further, leaf extract and Cetyltrimethyl ammonium bromide (CTAB) have been used as stabilizing and chelating agent to observe their effect on the structural, optical and morphological properties of the nanoparticles. The synthesized powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), ultraviolet visible (UV–visible) spectroscopy, Brunauer-Emmett-Teller (BET) analyser techniques. The detailed structural studies implied that the fabricated powders are akermanite and the average crystallite size was calculated to be in the range 23–27 nm. Field emission scanning electron microscopy analysis showed that the samples synthesized using water and leaf extract adopt rod like morphology while the sample fabricated using CTAB are seed shaped. The calculated bandgap of the developed powders from the UV-Visible reflectance spectra using Kubelka-Munk method lie in the range 3.1–3.26 eV. BET analysis revealed all the samples are mesoporous in nature and their specific surface area were estimated.

Redox and Kinetic Properties of Composition-Dependent Active Sites in Copper-Exchanged Chabazite for Direct Methane-to-Methanol Oxidation.

The CH4 oxidation performance of Cu-chabazite zeolites characterized by distinct Si/Al ratios and Cu loadings has been studied and the observed variations in reactivity have been correlated to the differences in the nature of the formed active centers. Plug flow reactor tests, in situ Fourier-transform infrared, and X-ray absorption spectroscopy demonstrate that a decrease in Cu loading shifts the reactivity/redox profile to higher temperatures and increases the CH3OH selectivity and Cu-efficiency. In situ electron paramagnetic resonance, Raman, ultraviolet-visible, Fourier-transform infrared, and photoluminescence spectroscopies reveal that this behavior is associated with the presence of monomeric Cu active sites, including bare Cu2+ and [CuOH]+ present at low Si/Al ratio and Cu loading. Formation of two distinct [Cu2(µ-O)]2+ moieties at higher Si/Al ratio or Cu loading forces these trends into the opposite direction. Operando electron paramagnetic resonance and ultraviolet-visible spectroscopy show that the apparent activation energy of monomeric Cu active species decreases with increasing Si/Al ratio, whereas the one of dimeric centers is unaffected.

The Binding Mechanism Between Cyclodextrins and Anticancer Drug Noscapine: A Spectroscopic and Molecular Docking Study.

In this paper the binding of noscapine (NOS) as an anticancer drug with poor bioavailability and low solubility with beta and methyl-beta cyclodextrins (β-CD and M-β-CD) as the biocompatible drug carriers were discussed using ultraviolet-visible, fluorescence and nuclear magnetic resonance spectroscopy, as well as molecular docking. The absorption of NOS changed when it was bound to both cyclodextrins, resulting in a hyperchromic shift. It formed a 1:1 stoichiometry inclusion complex with both cyclodextrins according to the Benesi-Hildebrand equation. The binding affinity was larger in NOS-M-β-CD (5.9 (± 0.66) × 103 M- 1) than NOS-β-CD (3.7 (± 0.22) × 103 M- 1) complex. The fluorescence emission band of NOS at 408nm was quenched when NOS was complexed with β-CD, and enhanced in the presence of M-β-CD, while the shoulder at 350nm was enhanced selectively when NOS was complexed with M-β-CD. The fluorescence quenching of NOS with β-CD showed a negative deviation from the Stern-Volmer. The thermodynamic parameters have been estimated with the help of the Van't Hoff equation in different temperatures, and a dynamic mechanism was proposed for quenching. Also, both ΔH and ΔS have positive values thus the main interactions result in hydrophobic forces. Moreover, the negative value of ΔG indicates that the bonding process is spontaneous. 1H NMR chemical shift changes were observable for NOS and both CDs protons due to the chemical environment changes of some nuclei upon complexation. The molecular docking results revealed that the 1:1 inclusion complex possesses a good molecular shape complementarity score for their most probable structures, and indicated that the M-β-CD inclusion system gave the higher complexation efficiency. The binding energy values for β-CD and M-β-CD were determined to be -6.7 and - 9.5kcal/mol, respectively. These findings suggest the same as the result of experimental tests that the NOS-M-β-CD complex is more stable than the NOS-β-CD complex.

Bio fabricated palladium nano particles using phytochemicals from aqueous cranberry fruit extract for anti-bacterial, cytotoxic activities and photocatalytic degradation of anionic dyes.

The low cost and ecological compatibility of green technology makes it superior to chemical approaches in the generation of metal nanoparticles. The current study shows the use of cranberry fruit extract in the environmentally friendly green production of palladium nanoparticles. It is well known that the fruit extract from cranberries has a rich phytochemical composition that makes it a useful bio reducing agent for the formation of PdNPs. Several spectroscopic techniques, including ultraviolet-visible spectroscopy (UV-vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX), were used to characterize the palladium nanoparticles (PdNPs). The diffractogram of the XRD analysis shows significant reflections at 39.98° (111), 46.49° (200), and 67.95° (220), which indicate the face-centered cubic (FCC) structure of PdNPs and demonstrate the crystallinity of the produced nanoparticles from the green method. The SEM and TEM structural and morphological analyses reveal that the synthesized nanoparticles have a spherical shape with size ranging between 2 nm to 50 nm. In addition, the synthesized PdNPs demonstrated possible antibacterial activity on both Gram-positive and Gram-negative bacteria as well as a cytotoxic effect on the MCF-7 breast cancer cell line. The degradation of Indigo Carmine (IC) and Sunset Yellow (SY) dyes can be effectively catalyzed by biogenic PdNPs, according to the results.

Effect of calcination temperature on structural, optical, and morphological properties of RAlO3 (R = La, Sm) perovskite oxides

RAlO3 (R = La, Sm) have attracted the research community due to their interesting optoelectronic properties and viable applications. The solution combustion method allows for a faster process and lower calcination temperature than the traditional solid-state method and is an economical alternative to wet chemical synthesis for producing RAlO3. This work explores the thermal, structural, morphological, optical, and electrical properties of RAlO3 (R = La, Sm) synthesised by the solution combustion method using urea as fuel. Thermogravimetric analysis—differential thermal analysis (TGA-DTA) showed the crystallization temperatures of lanthanum aluminate (LaAlO3) and samarium aluminate (SmAlO3) at 864 and 887 °C, respectively. The x-ray diffraction (XRD) and Rietveld analysis revealed the structure of LaAlO3 as rhombohedral (R-3c) and SmAlO3 as orthorhombic (Pbnm). The LaAlO3 and SmAlO3 samples calcinated at 800 °C showed crystallite size (D) of 19.26 nm and 19.06 nm, respectively. The field emission scanning electron microscopy (FE-SEM) images show a highly porous and large sheet-like morphology with voids and cracks. High resolution transmission electron microscopy (HR-TEM) images and the selective area electron diffraction (SAED) pattern show crystalline nature and the indexed planes agreed with the XRD results. The LaAlO3 and SmAlO3 samples had specific surface areas of 16.374 and 12.953 m2 g−1, respectively. The TGA-DTA results were affirmed by Fourier transform infrared spectroscopy (FT-IR) results which showed only the presence of metal-oxide bonds for materials annealed at and above 800 °C. These results were further validated by the electron dispersive x-ray spectroscopy (EDX) and the x-ray photoelectron spectroscopy (XPS) showing no additional peaks. The band gap of 5.08 and 4.82 eV were calculated from ultraviolet-visible spectroscopy (UV–vis) for LaAlO3 and SmAlO3, respectively. The results imply that the solution combustion technique using urea as fuel is a viable route for synthesising RAlO3.

Flavonoid Profiles in the Pulp of Different Lemon Cultivars and Their Antioxidant Activity Based on UPLC–Q–TOF–MS

Previous studies have indicated that there may be differences among the varieties of lemon flavonoids, but the details have not yet been made clear, which limits the comprehensive use of different cultivated lemon varieties. In this study, ultra-performance liquid chromatography–quadrupole–time-of-flight–mass spectrometry (UPLC–Q–TOF–MS) and ultraviolet–visible spectroscopy (UV–Vis) were used to investigate the types and contents of flavonoids in the flesh of the main cultivated variety (Eureka) and five common lemon varieties, as well as their in vitro antioxidant activity. A total of 21 compounds were identified, five of which were common compounds. Among them, Verna, Lisbon, and Bearss each have characteristic components that can serve as potential criteria for variety identification. Each of the six varieties of lemon has strong antioxidant activity. The antioxidant activity of different lemon varieties is related to flavonoids. Therefore, Eureka and the other five varieties of lemon are good natural antioxidants, and the cultivation and industrial production of lemons should consider the needs and selection of suitable varieties.

Preparation of Graphene Oxide (GO) incorporated-Polyvinylidene Fluoride (PVDF) Nanofiltration Membrane with Alkaline Post-Treatment for Textile Wastewater Treatment

The purpose of this research is to study the potential of polyvinylidene fluoride (PVDF) polymer incorporated with graphene oxide (GO), following with the alkaline etching post-treatment process for dye waste water treatment. Its anti-oxidation properties of PVDF, have led to its choice as a host polymer due to its high thermal stability, great organic selectivity, and excellent chemical and mechanical resistance. In addition, the post-treatment with a NaOH solutions of varied concentration ranging from 0 M to 0.2 M for 30 minutes was conducted in alter the morphology of the fabricated membrane with the aim to increase the perm-selectivity of the membranes. Besides, the fabricated membranes were further characterized in terms of the chemical and physical properties using Fourier-Transform Infrared Spectroscopy (FTIR), Contact Angle (CA), Ultraviolet Visible spectroscopy (UV-Vis), Atomic Microscopy (AFM) and Scanning Electron Microscopy (SEM). The experimental results showed that the post-treatment has decreased the membrane flux of dye wastewater. Based on the obtained result, as the concentration of NaOH solution increased, the permeability increased. While the overall dye rejection of the membrane remained of above 90 %.

Investigation of structural, elastic, thermal, magnetic, optical, and photocatalytic properties of nanosized Mg-Mn-Li ferrites

AbstractNanoferrites of (Mn1-xMgx)0.8Li0.1Fe2.1O4 (x: 0–1.0, step 0.2) were synthesized by the sol–gel autocombustion method. The structural properties of the samples were characterized by X-ray diffraction, particle size analysis, transmission electron microscopy, and Fourier transform infrared spectroscopy. The X-ray diffraction patterns for the samples establish the nanoscale (38–54 nm) pure-phase spinel cubic structure (Fd-$$\bar{3}$$ 3 ̅ m). Also, the particle size analysis results demonstrate the narrow distribution of their particle sizes, which range from 10 to 33 nm. The impact of Mg2+ ion concentration on the thermal, elastic, magnetic, and optical properties of these samples was studied. The saturation magnetization decreases from 56.9 to 31.1 emu/g, and the coercivity increases from 65.8 to 106.8G with the addition of Mg2+ ions, showing thin S-shaped hysteresis loops revealing the samples’ soft magnetic behavior. Thermal results indicate that these samples are interesting candidates for thermoelectric applications due to their noticeably lower thermal conductivity, which ranges from 0.3572 to 0.5881 W/mK. The optical band gap values determined by using ultraviolet-visible diffuse reflectance spectroscopy range from 5.11 to 5.25 eV, where quantum confinement for crystallite size triggers a larger band gap. As the concentration of Mg2+ ions increases, their ability to degrade methyl green dye under ultraviolet radiation for 100 min rises from 13.6 to 61.1% with the addition of H2O2, an indication of their photocatalytic activity. Moreover, the optimum ferrite sample, Mn0.4Mg0.4Li0.1Fe2.1O4, maintained its photocatalytic efficiency for at least six reaction cycles. Graphical Abstract

Enhanced photocatalytic activity of green synthesized zinc oxide nanoparticles using low-cost plant extracts

Developing stable and highly efficient metal oxide photocatalysts remains a significant challenge in managing organic pollutants. In this study, zinc oxide nanoparticles (ZnO NPs) were successfully synthesized using various plant extracts, pomegranate (P.M), beetroot roots (B.S), and seder, along with a chemical process. The produced ZnO NPs were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), Field Emission Scanning Electron Microscope (FESEM), High-Resolution Transmission Electron Microscopy (HRTEM), and Surface Area. For all prepared samples, the results indicated that the composition of the plant extract affects several characteristics of the produced particles, such as their photocatalytic properties, energy bandgap (Eg), particle size, and the ratio of the two intensity (0 0 2) and (1 0 0) crystalline planes. The particle size of the produced NPs varies between 20 and 30 nm. To examine NPs' photocatalytic activity in the presence of UV light, Methyl Orange (MO) was utilized. The Eg of ZnO synthesized by the chemical method was 3.16 e. V, whereas it was 2.84, 2.63, and 2.59 for P.M, Seder, and B.S extracts, respectively. The most effective ZnO NPs, synthesized using Beetroots, exhibited a degradation efficiency of 87 ± 0.5% with a kinetic rate constant of 0.007 min−1. The ratio of the two intensity (0 0 2) and (1 0 0) crystalline planes was also examined to determine a specific orientation in (0 0 2) that is linked to the production of oxygen vacancies in ZnO, which enhances their photocatalytic efficiency. Furthermore, the increase in photocatalytic effectiveness can be attributed to the improved light absorption by the inter-band gap states and effective charge transfer.

“Enhancing wastewater treatment: DFT and experimental insights into ZnO-implanted TiO2 Z-scheme photocatalyst mediated via Smilax aspera"

This comprehensive study aimed to optimize the performance of photogenerated carriers in catalytic and optoelectronic systems by effectively separating electron-hole pairs. Green-synthesized TiO₂ nanoparticles (average size ∼21 nm) and zinc acetate (99.5 % purity), augmented with eco-friendly integration of the plant Smilax aspera, resulted in a tailored hollow direct Z-scheme photocatalyst, ZnO–TiO₂, with adjustable ZnO loading ranging from 0.5 wt% to 5 wt%. Characterization techniques such as X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Ultraviolet–Visible Spectroscopy, Transmission Electron Microscopy, Thermogravimetric Analysis and Energy-Dispersive X-ray Spectroscopy provided detailed insights into the atomic and electronic properties of the material. The analysis revealed the coexistence of anatase TiO₂ and wurtzite ZnO phases, each exhibiting distinct electronic band structures within the composite. Density functional theory calculated band gap values of 2.02 eV for TiO₂ and 2.89 eV for ZnO–TiO₂ corroborated the experimental results, offering a deeper understanding of electronic transitions within the heterojunction. The ZnO–TiO₂ composite showed significant photocatalytic efficacy in degrading Methylene Blue (98 % in 15 min) and Rose Bengal (79.69 % in 40 min) under UV light. It also exhibited antifungal potential against Aspergillus niger and Candida albicans, with inhibition zones of 28.0 ± 0.12 mm and 30.23 ± 0.68 mm, respectively. This research provides valuable insights into the eco-friendly, multifunctional applications of the ZnO–TiO₂ Z-scheme photocatalyst. This research thus provides valuable insights into the multifaceted applications of this synergistic, eco-friendly heterojunction photocatalyst in environmental remediation and its role as an effective antifungal agent.

Fabrication of covalently bonded MoS2–graphene heterostructures with different organic linkers

Achieving stable and reliable 2D-2D van der Waals heterostructures remains challenging. The broadest strategy for synthesizing these heterostructures is growth or manually stacking one material on top of the other, yet it is inefficient. Here, we present a strategy for synthesizing covalently bonded MoS2-graphene heterostructures using organic linkers with two anchor sites at a low cost. Our covalent heterostructures exhibit a more homogeneously alternating structure than the corresponding randomly alternating structure of vdW heterostructures, as confirmed by surface-enhanced Raman spectroscopy (SERS) measurements. Moreover, different linkers can be used to adjust the interlayer distance between graphene and MoS2, leading to significant impacts on their optical and electrochemical properties, including Photoluminescence (PL), cyclic voltammetry (CV), Ultraviolet-visible spectroscopy (UV-Vis), and SERS. Our strategy offers opportunities to advance fundamental research and enable the practical application of 2D/2D van der Waals heterostructures in various fields, including optoelectronics, energy storage, and catalysis.

Study on Phytochemical Composition, Biosynthesis and Characterization of Zinc Oxide Nanoparticle Using Sargassum ilicifolium

Nanotechnology involves producing nanoscale materials with specific properties. Zinc oxide nanoparticles have potential applications in various fields. Due to toxic chemicals and environmental concerns, green methods using plants, fungi, bacteria, and algae have been adopted. An emerging area of nanotechnology is the green synthesis of nanoparticles using biological systems, particularly seaweed extracts. The green synthesis method has synthesized the zinc oxide nanoparticles using the aqueous extract of the brown seaweed Sargassum ilicifolium. The algal extract has greatly reduced the zinc acetate dihydrate salt solution to form zinc oxide nanoparticles. The synthesized zinc oxide (Zn-O) nanoparticles have been confirmed through Particle Size Analyzer (PSA), Raman spectroscopy, UltraViolet (UV)- Visible (Vis) spectroscopy, and Scanning Electron Microscope (SEM). The study used Scanning Electron Microscope (SEM) and Particle Size Analyzer (PSA) to examine the size and shape of the Zn-O nanoparticles. Raman spectroscopy and UltraViolet-Vis spectroscopy confirmed the formation of Zn-O nanoparticles. The SEM results exhibited a range of 24.4 nm to 83.4 nm. The occurrence of Zn-O nanoparticles was confirmed by Raman spectroscopy with peaks at 276.98 cm-1, 414.67 cm-1, 462.03 cm-1, 514.99 cm-1, and 998.28cm-1 and UltraViolet-Vis spectroscopy with peak at 370 nm. The present study also deals with the qualitative phytochemical constituent analysis using the aqueous extracts of Sargassum ilicifolium. Alkaloids, flavonoids, cardiac glycoside, tannins, amino acids, carbohydrates, and saponins were analyzed. Anthraquinone, anthocyanin, vitamin C, quinone, and phlobatannins were considered absent in the aqueous extract.

Applications of Nanozymes in Chiral-Molecule Recognition through Electrochemical and Ultraviolet-Visible Analysis.

Chiral molecules have similar physicochemical properties, which are different in terms of physiological activities and toxicities, rendering their differentiation and recognition highly significant. Nanozymes, which are nanomaterials with inherent enzyme-like activities, have garnered significant interest owing to their high cost-effectiveness, enhanced stability, and straightforward synthesis. However, constructing nanozymes with high activity and enantioselectivity remains a significant challenge. This review briefly introduces the synthesis methods of chiral nanozymes and systematically summarizes the latest research progress in enantioselective recognition of chiral molecules based on electrochemical methods and ultraviolet-visible absorption spectroscopy. Moreover, the challenges and development trends in developing enantioselective nanozymes are discussed. It is expected that this review will provide new ideas for the design of multifunctional chiral nanozymes and broaden the application field of nanozymes.

Cardioprotective effects of nanoparticles green formulated by Spinacia oleracea extract on isoproterenol-induced myocardial infarction in mice by the determination of PPAR-γ/NF-κB pathway

Abstract We developed a contemporary cardioprotective medication using silver nanoparticles (AgNPs) loaded with Spinacia oleracea to treat isoproterenol (ISO)-induced myocardial infarction in mice, focusing on the PPAR-γ/NF-κB pathway. The physicochemical techniques, such as Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, ultraviolet–visible spectroscopy, and energy dispersive X-ray analysis, were employed to characterize the AgNPs. In the in vivo experiment, myocardial infarction was induced in mice by administering ISO subcutaneously at a dose of 40 mg/kg every 12 h for a total of three times. The mice were divided into five groups in a random manner: (1 and 2) ISO + AgNPs at varying doses (10 and 20 μg/mL) and time points; (3) ISO; and (4) control. Following the treatment, cardiac function was assessed through electrocardiogram, as well as biochemical and histochemical analyses. In the study, we examined the inflammatory reactions and cell death in human coronary artery endothelial cells exposed to lipopolysaccharide (LPS). The PPAR-γ/NF-κB activation by LPS and the resulting cytokine production were checked using real-time PCR and western blot techniques. The typical ST segment depression in myocardial infarction mice is significantly inhibited by the administration of AgNPs. Additionally, the treatment with AgNPs leads to a significant improvement in ventricular wall infarction, a decrease in mortality rate, and inhibition of myocardial injury marker levels. Furthermore, the application of AgNPs resulted in a decrease in the inflammatory environment within the hearts of mice with myocardial infarction. This effectively prevented the increase in TNF-α, IL-1β, and IL-6. The gene expression normalization of PPAR-γ/NF-κB/IκB-α/IKKα/β and PPAR-γ phosphorylation could potentially be linked to the advantageous impacts of AgNPs. In the context of an in vitro experiment, the administration of AgNPs demonstrated a notable decrease in cell death and inflammation cytokines expression inhibition. The myocardial infarction mice in the pre + post-ISO group appear to experience more noticeable cardioprotective effects from the treatment with AgNPs than those in the post-ISO group. Our research findings demonstrate that AgNPs possess cardioprotective efficacies in ISO-induced myocardial infarction. This beneficial effect may be attributed to the PPAR-γ activation and the NF-κB signaling inhibition. Consequently, our study presents a novel remedial approach for myocardial infarction treatment in clinical settings.

Comparative analysis: particle size and bactericidal efficacy of zinc oxide nanoparticles with aloe vera gel versus aloe vera gel-honey

In the realm of nanoscience, the inherent antibacterial potential of nanoparticles (NPs) stands as an alluring prospect for the development of pharmaceutical interventions. Yet, conventional chemical and physical NPs fabrication methods pose environmental and safety concerns. The aim of this study is to greenly-synthesize zinc oxide nanoparticles (ZnO NPs) using aloe vera gel (AVG) and aloe vera gel-honey (AVG-honey) under different reactant-to-chemical reductant (or precursor-to-reducing agent) ratio conditions, facilitated by sonication. Structural and optical characteristics of synthesized ZnO NPs were explicated through Fourier Transformation Infrared Spectroscopy (FTIR) and Ultraviolet-visible Spectroscopy (UV–vis). Concurrently, x-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) delineated the crystalline disposition and morphological behaviors. The antibacterial susceptibility of ZnO NPs against Methicillin-resistant Staphylococcus aureus (MRSA) and Klebsiella Pneumoniae (K. pneumoniae) was investigated using the disc diffusion method. The structures of biosynthesized ZnO NPs were confirmed through distinctive peaks in FTIR and UV–vis spectra. XRD unveils hexagonal wurtzite crystallinity, while FESEM captured distinct morphologies, which are spherical and rice-shaped, in ZnO NPs/AVG, while ZnO NPs/AVG-honey revealed micro-size spherical structures surrounded by numerous tiny lumps. Notably, ZnO NPs/AVG at a 1:6 ratio exhibits a 26.5 nm size, showcasing superior antibacterial efficacy against MRSA (ZOI = 12 mm) and K. pneumoniae (ZOI = 13 mm) compared to other reactant-to-chemical reductant ratios and ZnO NPs/AVG-honey. In conclusion, the study revealed that ZnO NPs synthesized solely using AVG exhibited finer particle sizes and slightly enhanced antibacterial efficacy compared to ZnO NPs formulated with a combination of AVG and honey. This outcome shows that utilization of two reducing agents will contribute to large size of nanoparticles, thus reduce the efficiency of the antibacterial susceptibility. Moreover, the concentration ratios of reactants-to-chemical reductants emerged as crucial determinants in the nanoparticle synthesis process.

Influence of 60Co gamma radiation on the structural, morphological and optical properties of hydrothermally synthesized MoO3-CeO2 nanocomposite.

The influence of 60Co gamma radiation on Molybdenum Oxide-Cerium Oxide (MoO3-CeO2) nanocomposite is investigated in the present study. The MoO3-CeO2 nanocomposite was synthesized by conventional hydrothermal route. Ammonium hepta molybdate tetrahydrate [(NH4)6Mo7O24.4H2O] and cerium nitrate [Ce (NO3)3.4H2O] were used as the precursors. The composite was subjected to high energy gamma irradiation for different doses of 50, 100 and 150 kGy using 60Co gamma irradiation chamber. The structural study was carried out using X-ray diffraction, the morphological studies were carried out using scanning electron microscopy and ultraviolet-visible spectroscopy was carried out to study the optical properties before and after irradiation. The crystallite size was found to increase with increasing doses of gamma irradiation. The morphology of the samples shows that the nanoparticles tend to agglomerate with increasing doses of gamma radiation. The energy bandgap of the MoO3-CeO2 nanocomposite was calculated before and after irradiation and found to decrease with increasing doses of irradiation upto 100 kGy and then increases for 150 kGy.

Synthesis of gold nanoparticles coated with glucose oxidase using PVP as passive adsorption linkage

Gold nanoparticles (AuNPs) have great potential as biosensors for glucose detection due to their high sensitivity, as well as their extraordinary physical and chemical properties that improve compatibility with different biorecognition molecules, such as glucose oxidase (GOx). In this work the D-glucose quantification was determined by using the traditional technique based on biochemical reaction of GOx and AuNPs functionalized with polyvinylpirrolidone (PVP) polymer and the enzyme. The AuNPs-PVP-GOx nanocomplexes were characterized by ultraviolet-visible (UV-Visible), Infrared (FTIR), and Raman spectroscopies, as well as scanning electron microscopy (SEM), Z potential, dynamic light scattering (DLS), and thermogravimetry analysis (TGA). In general, these techniques showed significant differences after each functionalization stage with PVP and GOx, for instance it was observed: the presence of different functional groups, an increase of hydrodynamic diameter from 48.60 to 198.77 nm, a shift of the band absorption to larger wavelength, a change in the surface potential and weight loss, and in the morphology of the nanocomplex, which confirm the functionalization. In addition, the enzymatic activity of the AuNPs-PVP-GOx was confirmed through the detection of triiodide ions by UV-Visible spectrophotometry, coming from the oxidation reaction of iodide ions in the presence of H2O2. Furthermore, the nanocomplex synthesized by passive adsorption was evaluated as a possible biosensor for the quantification of D-glucose using a colorimetric assay, obtaining greater sensitivity than the traditional method. These findings indicate that PVP can be used as a linkage medium between AuNPs and GOx, which in turn can be used as a biosensor for the detection of D-glucose at low concentrations in biological fluids.

Concave Gold Nanocubes Exhibit Growth-Etching Behavior: Unexpected Morphological Transformations.

Chemical equilibrium stands as a fundamental principle governing the dynamics of chemical systems. However, it may become intricate when it refers to nanomaterials because of their unique properties. Here, we invesitigated concave gold nanocubes (CGNs) subjected to an akaline Au3+/H2O2 solution, which exhibit both etching and growth in a monotonic solution. When CGNs were subjected to an increasingly alkaline Au3+/H2O2 solution, their dimensions increased from 107 to 199 nm and then decreased to 125 nm. Transmission electron microscopy (TEM) demonstrated that their morphology undergoes intricate alternations from concave to mutibranch and finally to concave again. Real-time ultraviolet-visible spectroscopy and time-dependent TEM also demonstrated reduction first and then oxidation in one solution. Among the nanomaterials, the obtained carpenterworm-like gold nanoparticles revealed the best catalytic performance in p-nitrophenol reduction by NaBH4, with a chemical rate that continues to increase until the reaction reaches completion. Growth leading to atomic dislocation, distortion, and exposure on nanoparticles and the redox of H2O2 plausibly account for the further etching due to the Ostwald ripening effect. Our study may spur more interest in the tuning of the properties, engineering, investigation, and design of new kinds of nanomaterials.

Revisiting the structure of [PdAu9(PPh3)8(CN)]2+ produced by atmospheric pressure plasma irradiation of [PdAu8(PPh3)8]2+ in methanol.

Some of the authors of the present research group have previously reported mass spectrometric detection of [PdAu9(PPh3)8(CN)]2+ (PdAu9CN) by atmospheric pressure plasma (APP) irradiation of [MAu8(PPh3)8]2+ (PdAu8) in methanol and proposed based on density functional theory (DFT) calculations that PdAu9CN is constructed by inserting a CNAu or NCAu unit into the Au-PPh3 bond of PdAu8 [Emori et al., J. Chem. Phys. 155, 124312 (2021)]. In this follow-up study, we revisited the structure of PdAu9CN by high-resolution ion mobility spectrometry on an isolated sample of PdAu9CN with the help of dispersion-corrected DFT calculation. In contradiction to the previous proposal, we conclude that isomers in which an AuCN unit is directly bonded to the central Pd atom of PdAu8 are better candidates. This assignment was supported by Fourier transform infrared and ultraviolet-visible spectroscopies of isolated PdAu9CN. The simultaneous formation of [Au(PPh3)2]+ and PdAu9CN suggests that the AuCN species are formed by APP irradiation at the expense of a portion of PdAu8. These results indicate that APP may offer a unique method for transforming metal clusters into novel ones by generating in situ active species that were not originally added to the solution.