Field Emission Transmission Electron Microscopy Research Articles

Immunomodulatory responses of extracellular vesicles released by gram-positive fish pathogen Streptococcus parauberis

Bacterial extracellular vesicles (BEVs) are nanosized structures that play a role in intercellular communication and transport of bioactive molecules. Streptococcus parauberis is a Gram-positive pathogenic bacterium that causes “Streptococcosis” in fish. In this study, we isolated S. parauberis-derived extracellular vesicles (SpEVs), and then physicochemical and immunomodulatory properties were determined to elucidate their biological functions. Initially, the biogenesis of SpEVs was detected using field emission scanning electron microscopy, which revealed that secretory phase SpEVs attached to the outer surface of S. parauberis. SpEVs had an average particle diameter and zeta potential of 168.3 ± 6.5 nm and −17.96 ± 2.11 mV, respectively. Field emission transmission electron microscopy analysis confirmed the presence of round or oval-shaped SpEVs with clear membrane margins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis results showed three sharp protein bands when SpEVs were stained with Coomassie blue. In vitro toxicity of SpEVs was assayed using the murine macrophage RAW 264.7 cells and we observed no significant (p < 0.05) viability reduction up to 50 μg/mL qRT-PCR results revealed that SpEVs-treated (5 and 10 μg/mL) RAW 264.7 cells significantly (p < 0.05) induced the mRNA of proinflammatory (Il1β, Il6, and Tnfα) and anti-inflammatory (Il10) cytokines in a concentration-dependent manner. In vivo immunomodulatory effects of SpEVs were investigated by injecting SpEVs (5 and 10 μg/fish) into adult zebrafish. Transcriptional analysis based on qRT-PCR indicates significant (p < 0.05) upregulation of proinflammatory (il1β, il6, and tnfα) and anti-inflammatory (il10) genes in a concentration-dependent manner in zebrafish kidney. Further, protein expression results in zebrafish spleen tissue confirmed the immunomodulatory activity of SpEVs. In conclusion, SpEVs display the characteristics of BEVs and immunomodulatory activities, suggesting their potential application as vaccine candidate.

An improved immobilized molybdenum oxidative catalyst bearing an amino acid-derived bifunctional chelator

Herein we introduce a new glycine-bisphenol molybdenum(VI) complex, SBA@AP-GDC-Mo, immobilized on ordered mesoporous silica SBA-15 (Santa Barbara Amorphous) as an efficient and selective heterogenous catalyst. SBA@AP-GDC-Mo was fully characterized by Fourier transform-infra red (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), field emission-transmission electron microscopy (FE-TEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES) and Barrett–Joyner–Halenda (BJH) and Brunauer–Emmett–Teller (BET) adsorption isotherms. The catalytic performance of SBA@AP-GDC-Mo was evaluated in the chemoselective oxidation of sulfides to sulfoxides and sulfones and found to be superior to our previously reported diamine–bisphenol molybdenum(VI) catalyst. The advantages of SBA@AP-GDC-Mo include high activity and better chemoselectivity under mild and eco-friendly conditions (e.g., ambient temperature using aqueous or aqueous–ethanolic solutions), recyclable for at least four cycles and easier overall synthesis in good yields including tethering of the ligand to the support.

New role of ionic liquid as accelerator activator in rubber compounds and its influence on curing and mechanical properties

AbstractThis study focuses on the effect of ionic liquids (ILs) on the cure characteristics and filler dispersion of natural rubber (NR) and styrene‐butadiene rubber (SBR) gum and filled compounds. The complexation of ionic liquid with zinc oxide (ZnO) increases the activity of ZnO and the cure rate together with improved filler dispersion. This has also increased the rubber filler interaction. Imidazolium and chloride based ionic liquids with different cationic groups were compared and characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, and differential scanning calorimetry to understand the thermal and chemical behavior of the compounds. Interestingly, it was found that the ionic liquid can act as an activator and is able to accelerate the vulcanization rate with improved rubber filler interaction. The complexes formed by IL‐Zn were shown to be much more reactive than Zn‐stearic acid complexes. The dispersion of carbon black in the NR and SBR compounds was studied by using Field Emission Scanning Electron Microscope and Transmission Electron Microscope and the results demonstrate that ILs could significantly improve the filler dispersion. Thus, this study has revealed the multifunctional role of ionic liquids in rubber compounds.Highlights This article describes the dual role of the ionic liquid (IL) in rubber compounds. It can act both as an accelerator‐activator as well as an efficient dispersing aid. The complexation of IL with zinc oxide (ZnO) plays a crucial role in enhancing the activity of ZnO. As a result, the physico‐mechanical properties of both natural rubber and styrene‐butadiene rubber based compounds are significantly improved.

Hydrogen production from sodium borohydride using Co nanoparticles

In this study, hydrogen [H2(g)] production from sodium borohydride (NaBH4) using cobalt (Co) nanoparticles (NPs) was investigated with a hydrolysis process. Optimum experimental conditions were examined at different hydrolysis times (5, 10, 20, 30, 40, 50, 60, 70, 80, and 90 min), at different hydrolysis temperatures (25, 35, 45, and 65oC), and at increasing Co NPs nanocatalyst concentrations (5, 15 and 30 mg/l) at pH = 13.0, respectively. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM) analyses were performed for characterization studies. H2(g) measurements were made in gaschromatography–mass spectrometry (GC-MS). The maximum 81% H2(g) yield was observed before the hydrolysis process after 90 min, at pH = 13.0, at 25 oC. The maximum H2(g) yields were recorded as 98% after 45 min hydrolysis times at 45 oC, at a pH of 13.0. 99% H2(g) yields were found after 14 min hydrolysis times, at pH a pH of 13.0 at 65 oC. The maximum NaBH4 concentration and using Co NPs concentrations were kept constant at 300 mg/l and 1.5 mg/l, respectively.

Fabrication of hierarchical Mn-Co-P nanospheres as positive electrode material for ultra-stable asymmetric supercapacitor

Herein, the novel Mn-Co-P nano-spheres and acacia wood-derived activated carbon (ACWC) as positive and negative electrodes, respectively, were used to develop an ultra-stable asymmetric supercapacitor. The Mn-Co-P nano sphere was synthesized by a hydrothermal method to give distinct characterization morphology and electrochemical performance. Detail with regard to its physical and chemical properties of the active material coated on the nickel substrate are studied by X-ray diffraction, field-emission scanning electron microscopy, field-emission transmission electron microscopy, high-resolution X-ray photoelectron spectroscopy analyses, thermogravimetric analysis (TGA), and N2 adsorption-desorption isotherms. The electrochemical properties of the prepared materials were tested in electrolyte by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Results show that the Mn-Co-P electrode has a high specific capacity of 119.34 mAh g−1 at 0.5 A g−1 current density. The ACWC active carbon was prepared from acacia wood to give a high surface area of 1210 m2g−1, with a high specific capacitance of 225 F g−1 at 0.5 A g−1. Asymmetric supercapacitor devices based on the electrodes exhibit a high energy density of 36.2 Wh kg−1 at 850.00 W kg−1. In addition, outstanding cycling number stability of 93.3 % capacitance retention over 10,000 cycles was achieved using sodium sulphate (0.5 M) as an electrolyte.

Complementary metalloporphyrin-based nanostructure decorated with silver nanoparticles for photocatalytic degradation of organic dyes

A hybrid composite photocatalyst, SA-T@Ag, was fabricated by the photoreduction of silver salts in the presence of nanomaterials composed of self-assembled complementary porphyrin triad SA-T. We confirmed the formation of SA-T@Ag from SA-T using various spectroscopic techniques, including X-ray diffraction (XRD), infrared (IR) spectroscopy, UV–visible spectroscopy, and fluorescence spectroscopy. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) investigations revealed that a substantial amount of silver nanoparticles (AgNPs) were deposited on the surface of SA-T and that the microstructure of SA-T was intact during photoreduction. The formation of AgNPs on the surface of SA-T reduced the band gap energy (Eg) of SA-T@Ag compared to that of SA-T. This not only improves its light-harvesting properties but also delays the recombination of photogenerated electron-hole pairs, which promotes more reactivity under visible light irradiation and improves the efficiency of polluted dye degradation. These photophysical properties are reflected in the degradation of methylene blue (MB) dye under visible light irradiation. The first-order degradation rate constant of MB dye within 45 min of visible light irradiation is much higher for SA-T@Ag (0.081 min−1) than SA-T (0.028 min−1). This report is of great importance in the field of environmental remediation and provides new opportunities for designing porphyrin-based photocatalytic systems as alternatives to conventional photocatalysts.

جسيمات النحاس النانوية المركبة في مصفوفة البوليمر الحيوي وتطبيقاتها في النشاط المضاد للبكتيريا

النحاس هو بديل أرخص من العديد من المعادن النبيلة مع مجموعة من التطبيقات المحتملة في مجال علم النانو وتكنولوجيا النانو. ومع ذلك ، فإن جسيمات النحاس النانوية لها قيود كبيرة ، والتي تشمل الأكسدة السريعة عند التعرض للهواء. لذلك ، تم تطوير مسارات بديلة لتجميع الجسيمات النانوية المعدنية في وجود البوليمرات والمواد الخافضة للتوتر السطحي كمثبتات ، ولتشكيل الطلاءات على سطح الجسيمات النانوية. هذه المواد الخافضة للتوتر السطحي والروابط البوليمرية مصنوعة من بتروكيماويات غير متجددة. نظرًا لمحدودية الموارد الأحفورية ، فإن إيجاد بديل متجدد وقابل للتحلل البيولوجي يعد أمرًا واعدًا ، حيث هدفت الدراسة إلى إعداد وتوصيف وتقييم الخصائص المضادة للبكتيريا لجسيمات النحاس النانوية. تم تحضير جسيمات النحاس النانوية باستخدام البوليمر الحيوي الجيلاتيني ، أيونات CuSO4.5H2O والهيدرازين كمثبت ، ملح سلائف وعامل اختزال على التوالي. ومع ذلك ، تم استخدام محلول فيتامين C و NaOH أيضًا كمضاد للأكسدة وضبط درجة الحموضة. تم تمييز جسيمات النحاس النانوية المركبة باستخدام التحليل الطيفي المرئي للأشعة فوق البنفسجية (UV-vis) ، التحليل الحراري الوزني (TGA) ، مسحوق قياسات زيتا المحتملة ، حيود الأشعة السينية (XRD) ، المجهر الإلكتروني لمسح الانبعاث الميداني والمجهر الإلكتروني النافذ (TEM). يؤكد طيف الامتصاص المرئي للأشعة فوق البنفسجية تكوين CuNPs ، والتي أظهرت أقصى امتصاص عند 583 نانومتر. أشارت النتائج التي تم الحصول عليها من TEM إلى انخفاض في حجم الجسيمات من التركيز المنخفض إلى التركيز العالي للمواد الداعمة. وجد أن التركيز الأمثل للجيلاتين هو 0.75٪ بالوزن. المواد الداعمة المستخدمة في هذا التركيب متوافقة حيوياً والمنتجات التي تم الحصول عليها مستقرة في الهواء. تُظهر CuNPs المُصنَّعة أنشطة واعدة مضادة للجراثيم ضد B. subtilis (B29) و S. aureus (S276) و S. choleraesuis (ATCC 10708) و E. coli (E266) كبكتيريا موجبة وسالبة الجرام على التوالي.

Growth of Ni loaded CdS in nanorods structure for photocatalytic and dye degradation applications under solar irradiation

Due to the exponential increase in global energy consumption and the degradation of environmental conditions caused by fossil fuels, it is critical to improve inexhaustible and sustainable resources. Generally, solar energy is one of the clean and environmentally agreeable energy sources. By harvesting solar energy for photocatalysis and considering it as a promising solution for various energy generation applications such as hydrogen production. Herein we are using Cadmium Sulphide and Nickel-doped Cadmium Sulphide in 0.5, 1 and 5 weight percent which act as photocatalyst for water splitting which will eventually produce an enormous amount of Hydrogen (H2). Cadmium sulphide was prepared through the chemical precipitation method and Ni-CdS by hydrothermal technique. The purity and phase formation were examined by the X-ray diffraction (XRD) and validated via Rietveld refinement by using Full Prof software. The surface morphology and the structure of as-synthesized material were evaluated by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscope (TEM) spectroscopic techniques. Following the results, the Ni-CdS nanocomposite having 1.0 wt% of Ni exhibits the highest H2 evolution rate of 9 mmolg−1 in 5 h with strong photo-stability, which is about 50 times higher than that of CdS. The material was tested to degrade organic dye for its photocatalytic operations. The newly prepared composite materials (CdS-Ni-NiO) were used for the photocatalytic degradation of the methylene blue (MB) dye. Ni(1.0 wt%)-CdS shows an optimal degradation percentage of 95.436 in the presence of artificial solar light in 90 min. Crystal growth mechanism shows the spherical structure of CdS agglomerate to form nanorods structure when doped with Ni metal which is also verified by the TEM images of CdS and Ni-doped CdS. The XPS peaks observed at 854.88 eV and 861.07 eV for Ni2+ with an energy separation of 6.18 eV confirmed the existence of NiO with Ni/CdS. The Raman bands of pure CdS and Ni (1.0 wt%)-CdS nanorods were observed at 300 cm-1 and 293 cm−1 for 1LO phonon and 601 cm−1 and 586 cm−1 for 2LO phonon corresponds. The Ni tuned the CdS band gap from 2.36 to 2.20 eV. The results pave the way for designing multi-component CdS-Ni nano-composites for highly efficient H2 evolution and other environmental applications.

Improved optical and electrical response by glancing angle synthesized Al2O3 nanorod array device

An Aluminum Oxide (Al2O3) nanorod (NR) array–based device has been synthesized upon an Al2O3 thin film (TF) by electron beam (E-beam) evaporation with a glancing angle deposition technique. The complete fabrication has been done inside a vacuum coating unit. The Al2O3 nanostructures have been fabricated on a silicon substrate. Field emission scanning electron microscopy and transmission electron microscopy show a vertically aligned Al2O3 NR array. From the Tauc plot, the optical band energies are estimated as 5 eV and 5.5 eV for the bare Al2O3 TF and Al2O3 NR/Al2O3 TF devices, respectively. Significant improvement has been observed in photosensitivity by 10 fold, detectivity by 4.2 fold, and noise equivalent power (NEP) by 16.5 fold for the Al2O3 NR/Al2O3 TF device compared with the Al2O3 TF. The Al2O3 NR/Al2O3 TF device exhibits a very fast photoswitching response (rise time = 0.15 s and fall time = 0.13 s). Therefore, the Al2O3 NR/Al2O3 TF device proves to be a prominent candidate for next-generation optoelectronic device applications.

Polyamine functionalized cage hollow mesoporous SiO2 microspheres for CO2 capture over a wide temperature range

Hollow SiO2 microspheres have become attractive materials for nanotechnology applications owing to their biological inertness and high functionality. In this study, hydrophobic spherical hollow cages were formed using the soft stencil method with Pluronic F127 and cetyltrimethylammonium bromide (CTAB) as the structure-directing agent, and hollow nanoporous SiO2 microspheres (FHMS) were prepared using the soft template method. Various of amine functionalization modes were further employed to demonstrate the complexity of the relationship between pore structure/amidation mode/amine content and adsorption capacity. The hollow morphology of the porous silica was revealed using field-emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and its porous properties were revealed using nitrogen adsorption-desorption isotherm measurements. Experiments on the fixed-bed dynamic adsorption process at 15% CO2 showed that the high specific surface area, high pore volume and amine content of the carriers had a positive effect on the adsorption performance. However, the accessibility of the adsorption centre was affected at high loadings, and the amine efficiency and adsorption capacity were reduced. The dual amine functionalized FHMS-G-I60 maintained the integrity and order of the hollow mesoporous carrier structure, and overcame the dilemma of easy loss in the cycle process of the impregnation method and the low adsorption capacity of the grafting method. It possessed an adsorption capacity of 3.62 mmol/g, high adsorption cycling stability (more than 99.5% adsorption maintained after 10 cycles) and high amine efficiency (0.2852 mmol CO2/mmol N). CO2-TPD analysis (Thermal Programmed Desorption) further showed that FHMS-G-I60 had a faster desorption rate and lower regeneration energy consumption. In general, such structure-directed prepared matrices and functionalized with different amines are promising and low-cost adsorbents that can be used to capture CO2 from ambient air and flue gases under different demands.

Biogenic Synthesis and Characterisation of Flueggea leucopyrus Willd Leaf Mediated Copper Nanoparticles for Antibacterial, Antioxidant, and Antidiabetic Activities

IntroductionThe chemical synthesis of metal Nanoparticles could be changed into green synthesis if solvents, stabilising agents, and reducing agents are environmentally friendly. Our aims were to synthesise and characterise bioconjugated copper nanoparticles (CuNPs) and evaluate their antibacterial, antioxidant, and antidiabetic activities. MethodsThis study was made to synthesise CuNPs using Flueggea leucopyrus Willd leaf extract. The produced CuNPs were characterised using UV-visible, Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), TEM, EDX, and Zeta-potential analytical methods. The antibacterial, antioxidant, and antidiabetic properties of CuNPs were screened through disc diffusion methods, 2,2-diphenyl-1-picrylhydrazyl radical quenching, and alpha-amylase inhibition assay, respectively. ResultsThe CuNPs are poly-dispersed, spherical, crystalline, and stable with an average particle size of 20 nm. These nanoparticles show antibacterial activity and exhibit the same inhibition zone against S aureus and P aruginosa (13 mm), a strong zone for E faecalis, and no inhibition zone for E coli bacteria. The CuNPs demonstrated dose-dependent sequencing and inhibition activities with an IC50 value of 100.06 ppm and 435.68 ppm, respectively. ConclusionsThis study shows that these poly-disperse CuNPs could act as a bacterial resistance agent, antioxidant, and antidiabetic drug. It concluded that CuNPs made from medicinal plant leaf extract have good inhibitory potential against alpha-amylase, one of the main pharmacological targets for treating type 2 diabetes.

The inhibition effects of Lentilactobacillus buchneri-derived membrane vesicles on AGS and HT-29 cancer cells by inducing cell apoptosis

In recent years, probiotics and their derivatives have been recognized as important therapeutic agents in the fight against cancer. Therefore, this study aimed to investigate the anticancer effects of membrane vesicles (MVs) from Lentilactobacillus buchneri strain HBUM07105 probiotic isolated from conventional and unprocessed yogurt in Arak province, Iran, against gastric and colon cancer cell lines. The MVs were prepared from the cell-free supernatant (CFS) of L. buchneri and characterized using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) and SPS-PAGE techniques. The anticancer activity of MVs was evaluated using MTT, flow cytometry, qRT-PCR techniques, and a scratch assay. The study investigated the anti-adenocarcinoma effect of MVs isolated from L. buchneri on a human gastric adenocarcinoma cell line (AGS) and a human colorectal adenocarcinoma cell line (HT-29) at 24, 48, and 72-h time intervals. The results demonstrated that all prepared concentrations (12.5, 25, 50, 100, and 200 µg/mL) of MVs reduced the viability of both types of human adenocarcinoma cells after 24, 48, and 72 h of treatment. The analysis of the apoptosis results revealed that the percentage of AGS and HT-29 cancer cells in the early and late stages of apoptosis was significantly higher after 24, 48, and 72 h of treatment compared to the untreated cancer cells. After treating both AGS and HT-29 cells with the MVs, the cells were arrested in the G0/G1 phase. These microvesicles demonstrate apoptotic activity by increasing the expression of pro-apoptotic genes (BAX, CASP3, and CASP9). According to the scratch test, MVs can significantly decrease the migration of HT-29 and AGS cancer cells after 24, 48, and 72 h of incubation compared to the control groups. The MVs of L. buchneri can also be considered a potential option for inhibiting cancer cell activities.

Enhancing Electrochemical Non-Enzymatic Dopamine Sensing Based on Bimetallic Nickel/Cobalt Phosphide Nanosheets.

In this study, the successful synthesis of bimetallic nickel/cobalt phosphide nanosheets (Ni-Co-P NSs) via the hydrothermal method and the subsequent high-temperature phosphorization process were both confirmed. Ni-Co-P NSs exhibited excellent electrocatalytic activity for the electrochemical non-enzymatic DA sensing. The surface morphologies and physicochemical properties of Ni-Co-P NSs were characterized by atomic force microscopy (AFM), field-emission scanning (FESEM), field-emission transmission electron microscopy (FETEM), and X-ray diffraction (XRD). Further, the electrochemical performance was evaluated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The metallic nature of phosphide and the synergistic effect of Ni/Co atoms in Ni-Co-P NSs provided abundant catalytic active sites for the electrochemical redox reaction of DA, which exhibited a remarkable consequence with a wide linear range from 0.3~50 μM, a high sensitivity of 2.033 µA µM-1 cm-2, a low limit of detection of 0.016 µM, and anti-interference ability. As a result, the proposed Ni-Co-P NSs can be considered an ideal electrode material for the electrochemical non-enzymatic DA sensing.

Insight into the inhibitory activity and mechanism of bovine cathelicidin BMAP 27 against Salmonella Typhimurium

This study synthesized an antimicrobial peptide based on the bovine cathelicidin BMAP 27 sequence. It was found to have a broad spectrum of antibacterial activity, with exceptionally high activity against Salmonella. However, the antibacterial mechanism of BMAP 27 against Salmonella remains unclear. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of BMAP 27 against Salmonella enterica serovar Typhimurium were determined to be 2 μM and 4 μM, respectively. After treatment with 2 MIC of BMAP 27, the absorbance of DNA in centrifugal supernatant increased from 0.244 to 1.464, and that of protein rose from 0.174 to 0.774, respectively. BMAP 27 has compromised the cell membrane as observed through field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM), and confirmed by the propidium iodide (PI) test. The alkaline phosphatase (AKP) enzyme activity in the supernatant of the 2 MIC treatment group was 2.15 times higher than the control group, indicating extracellular membrane damage. BMAP 27 treatment increased intracellular ROS levels as tested by dichlorofluorescein diacetate (DCFH) staining. DNA interaction analysis revealed that BMAP 27 has a binding affinity towards DNA, causing its characteristic bands to disappear and peak intensity at 260 nm to reduce. Molecular docking identified its potential binding mode with DNA. The crystal violet biofilm staining results demonstrated that BMAP 27 inhibited S. Typhimurium biofilm formation by 43.1 % and cleared mature biofilms by 53.62 %. Confocal Laser scanning electron microscopy (CLSM) observed that BMAP 27 could kill bacteria within the biofilm and dislodge bacteria from the surface of glasses. Swimming tests identified that the motor capacity of S. Typhimurium was diminished by BMAP 27. By counting the total bacteria, BMAP 27 was revealed to exert bacteriostatic effects in chilled pork and orange juice, which might provide a basis for its application in the inhibition of Salmonella.

Self‐templated magnesiothermic reduction of ORMOSIL particles to monodisperse hollow spherical SiC composite particles

AbstractHollow silicon carbide (SiC) particles have attracted attention due to their well‐defined morphology, low density, and large surface area that can be leveraged for a wide variety of applications. Here, we report the self‐templated synthesis of monodisperse hollow spherical SiC composite particles with controllable shell thicknesses using magnesiothermic reduction of organically modified silica (ORMOSIL) particles. Monodisperse ORMOSIL particles containing three organic groups of methyl, vinyl, and mercaptopropyl were produced by a simple one‐pot sol–gel process and then converted to hollow spherical SiC composite particles via a magnesiothermic reduction at 700°C under an inert atmosphere. The spherical morphologies of the original ORMOSIL particles were well maintained through this self‐templated conversion process, but the sizes of the hollow SiC particles were slightly reduced by the thermal treatment. Field emission transmission electron microscopy studies revealed that the shell of hollow particles mainly consists of primary β‐SiC particles with nanometer‐scale sizes. The physical and chemical properties of the hollow SiC composite particles were investigated by scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectroscopy, Brunauer–Emmett–Teller, X‐ray diffraction, Fourier transform infrared spectroscopy, Raman, and solid‐state nuclear magnetic resonance analyses. The shell thickness of hollow spherical SiC composite particles can be controlled by simply changing the duration of the thermal conversion process. This study not only provides a simple and easy approach for the preparation of hollow spherical SiC particles but also opens the possibility of large‐scale manufacturing of such particles for commercial applications.

Synthesis and characterization of gold nano particles using barleria cristata for antimicrobial and anticancer applications

A nano revolution is necessary for the integration of nanoscience and medicine. Drug delivery, electronics, biological sciences, optics, and catalysis are among the fields in which metal nanoparticles find application. The objective of this work is to extract leaves from Barleria cristata in order to produce ecologically friendly gold nanoparticles (Au NP) for pharmacological studies. Several human pathogens were used to assess the biological mechanism and antibacterial properties of gold nanoparticles (AuNPs) in relation to their potential as a cancer treatment. An aqueous extract with a natural pH of 7.4 was obtained by reacting with 1 mM chloroauric acid (HAuCl4.3H2O), and it was then kept at room temperature. The colour changed from pale yellow to pink right away, indicating the reduction of Au3+ ions to Au 0. Using a UV-Visible spectrophotometer, the synthesised AuNPs were seen. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), field emission transmission electron microscopy (FE-TEM), and particle size distribution and zeta potential analysis are a few examples of analytical techniques. The disc diffusion method was used to confirm the extract's antibacterial properties in vitro on a few human illnesses. The MTT test was used to confirm the extract's anticancer properties on Hela carcinoma cell lines, revealing IC50 values of 50 μg/mL.

Role of oxygen functional groups and attachment of Au nanoparticles on graphene oxide sheets for improved photodetection performance.

Integrating low-dimensional graphene oxide (GO) with conventional Si technology offers innovative strategies for developing ultrafast wideband photodetectors. In this study, we synthesized GO and explored its potential application in broadband photodetection alongside silicon heterostructures. The as-synthesized GO contains various oxygen functional groups, as evidenced by X-ray photoelectron and Fourier transform infrared spectroscopy. These functional groups contribute to increased photo absorption, enhancing photodetection performance. The systematic reduction of these functional groups from the GO surface via thermal annealing decreases photo absorption and consequently lowers the photocurrent. This reduction diminishes photo absorption and amplifies the dark current by approximately 25 times, from 20 nA to 496 nA. This dark current increase is attributed to the electron mobility following the reduction of functional groups. However, attaching plasmonic gold nanoparticles (Au NPs) to the GO surface enhances UV-Vis absorption in the visible region, enabling broadband detection. The even distribution of attached Au NPs on the GO surface is confirmed through field emission transmission electron microscopy. While thermal annealing of GO diminishes the responsivity from 4.6 A W-1 to 3.0 A W-1, the attachment of Au NPs augments the responsivity by more than two-fold, reaching 10.0 A W-1. Thus, it highlights the importance of rich oxygen functional groups in GO and the attachment of Au NPs to achieve more efficient photo-sensing properties.

Enhanced supercapacitor performance of a Cu-Fe2O3/g-C3N4 composite material: synthesis, characterization, and electrochemical analysis.

A Cu-doped Fe2O3/g-C3N4 composite, synthesized via a straightforward hydrothermal process with controlled morphologies, represents a significant advancement in supercapacitor electrode materials. This study systematically analyzes the impact of Cu doping in Fe2O3 and its synergistic combination with g-C3N4 to understand their influence on the electrochemical performance of the resulting composite, focusing on Cu doping in Fe2O3 rather than varying Fe2O3/g-C3N4 content. The comprehensive characterization of these composites involved a suite of physicochemical techniques. X-ray diffraction (XRD) confirmed the successful synthesis of the composite, while field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were employed to investigate the morphological attributes of the synthesized materials. X-ray photoelectron spectroscopy (XPS) spectra confirmed the elemental composition of the composite with 6% Cu doped Fe2O3/g-C3N4. The composite electrode, which incorporated 6% Cu doped Fe2O3 with g-C3N4, exhibited exceptional cycling stability, retaining 94.22% of its capacity even after 2000 charge-discharge cycles at a current density of 5 mA cm-2. Furthermore, this Cu doped Fe2O3/g-C3N4 composite electrode demonstrated impressive electrochemical performance, boasting a specific capacitance of 244.0 F g-1 and an impressive maximum energy density of 5.31 W h kg-1 at a scan rate of 5 mV s-1. These findings highlight the substantial potential of the Cu doped Fe2O3/g-C3N4 electrode for supercapacitor applications.

Thermal, morphological and surface properties of composite materials with perlite reinforcement

This paper deals with the preparation and characterization of perlite/polyvinyl alcohol, perlite/polyvinylpyrrolidone, perlite/polymethyl methacrylate, and perlite/polystyrene composites. Polymer composites were prepared by solvent casting technique with 5 wt. % of perlite filler. Perlite is a filler with unique properties, such as low density and thermal conductivity, thus the development of Polymer-Perlite composites may be interesting for producing lighter packaging with thermal insulation capability. The perlite/polymer nanocomposites were characterized using X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), inverse gas chromatography (IGC), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). TGA measurements showed remarkable increases in the thermal stability of the polystyrene by the perlite loading as compared to the matrix. The FE-SEM image of the cryomilled sample shows that the perlite particles were embedded within a polystyrene matrix. This finding is consistent with the work of adhesion data obtained by IGC.

A chemically engineered water-soluble block copolymer for redox responsive SO2 release in antibacterial therapy.

Sulfur dioxide (SO2) has emerged as a promising gasotransmitter for various therapeutic applications, including antibacterial activities. However, the potential of polymeric SO2 donors for antimicrobial activities remains largely unexplored. Herein, we report a water-soluble, redox-responsive, SO2-releasing amphiphilic block copolymer poly(polyethylene glycol methyl ether methacrylate) (PPEGMA)-b-poly(2-((2,4-dinitrophenyl)sulfonamido)ethyl methacrylate (PM)) (BCPx) to investigate their antibacterial properties. BCPx contains hydrophilic polyethylene glycol (PEG) pendants and a hydrophobic SO2-releasing PM block, facilitating the formation of self-assembled nanoparticles (BCPxNp) in an aqueous medium, studied by critical aggregation concentration (CAC) measurements, dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). BCPxNp exhibits sustained SO2 release up to 12 h in the presence of glutathione (GSH), with a yield of 30-80% of theoretical SO2 release. In vitro antibacterial studies unveil the outstanding antibacterial activity of BCP3Np against Gram-positive bacteria Bacillus subtilis, as evidenced by FESEM and live/dead cell fluorescence assay. We further elucidate the antibacterial mechanism through reactive oxygen species (ROS) generation studies. Overall, the polymer exhibits excellent biocompatibility at effective antimicrobial concentrations and provides insights into the design of a new class of SO2-releasing polymeric antibacterial agents.