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Grape seed extract (GSE) is a natural source of polyphenolic compounds and secondary metabolites, which have been tested for their possible antimicrobial activities. In the current study, we tested the antibacterial and antifungal activities of aqueous GSE and the biosynthesized silver nanoparticles loaded with GSE (GSE-AgNPs) against different pathogens. The biosynthesized GSE-AgNPs were assessed by UV spectroscopy, dynamic light scattering (DLS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), and gas chromatography/mass spectrometry (GC/MS). The antimicrobial activities were assessed against different bacterial and fungal species. DLS analysis showed that GSE-AgNPs had a Z-Average of 91.89 nm while UV spectroscopy showed that GSE-AgNPs had the highest absorbance at a wavelength of ~415 nm. FTIR analysis revealed that both of GSE and GSE-AgNPs consisted of different functional groups, such as hydroxyl, alkenes, alkyne, and aromatic rings. Both FE-SEM and TEM showed that GSE-AgNPs had larger sizes and rough surfaces than GSE and AgNO3. The results showed significant antimicrobial activities of GSE-AgNPs against all tested species, unlike GSE, which had weaker and limited effects. More studies are needed to investigate the other antimicrobial activities of GSE.

This study investigates the effect of silver, titanium dioxide, and silver, Zirconium dioxide nanoparticles on the flexural strength of self-cured denture base resin. The samples were divided into four groups according to the addition of different nanoparticles to the self-cured acrylic PMMA. Control group A, reinforcement group B (Ag + TiO2), reinforcement group C (Ag + ZrO2) and reinforcement group D (Ag + TiO2 + ZrO2). The samples were again divided into three subgroups according to the nanoparticulate addition ratio of 0.1, 0.3 and 0.5 wt.% TiO2 and ZrO2 each with a fixed ratio of 0.3wt.% Ag as antimicrobial. Excluding group D addition, it was 0.05, 0.15, 0.25 wt.% for both TiO2 and ZrO2 with 0.3 wt.% Ag. After immersing the samples in distilled water for 48h, the flexural strength was measured using the three-point bend test. Evaluation of flexural strength showed a significant decrease with an increasing percentage of nanoparticles, except the increase in the percentage of additions of ZrO2 showed an increase in flexural strength. The samples underwent X-ray diffraction examination and FESEM to describe nanoparticles and examine the structure of acrylic samples. X-ray diffraction revealed the absence of mistake diffraction, indicating high crystal structure purity. In addition, images from the scanning electron microscope showed a homogeneous distribution of nanoparticles within the acrylic structure. Maximum flexural strength was seen in the 0.3 wt.% Ag-0.15 wt.% TiO2-15 wt.% ZrO2 and minimum in 0.3 wt.% Ag -0.5 wt.% TiO2. The modified samples also exhibited colour changes. We conclude flexural strength value depends on the percentage of additions and type of nanoparticles.

A simple, affordable and green method for synthesis gold (Au) and sliver (Ag) nanoparticles (NPs) has been adopted using Thyme plant (Thymus kotschyanus) extract. The plant extract, being rich in polyphenolic compounds, act as natural green reducing agent to generate noble metal NPs in situ from their corresponding ions. The structural and physical characteristics of the synthesized nanoparticles were ascertained over Ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Transmission electron microscopy (TEM) analysis. Both of the NPs displayed Surface Resonance Plasmon (SPR) excitation. The Synthesized Ag/Thyme NPs and Au/Thyme NPs catalytically explored in the reduction of 4-nitrophenol in presence of sodium borohydride as hydrogen donor. While used in different concentrations (100 µg/mL, 200 µg/mL and 300 µg/mL) as catalyst, it was seen that the activity gradually increased with higher catalyst load. The kinetic study of the reactions was also performed using the UV–Vis analysis data. All the reactions were of pseudo first order kinetics. The catalysts were isolated by centrifuge and recycled 6 successive times without any significant loss of its catalytic activity. As a result, at the same conditions, the reaction in the presence of Au NPs is faster than the reaction in the presence of Ag NPs. In summary, the noble gold and silver nanoparticles were synthesized over Thyme plant extract in a bio-inspired pathway.

In the present work, silver nanoparticles (AgNPs) were prepared by a simple and green method using carrageenan as reducing and capping agent. The as-synthesized carrageenan-AgNPs was demonstrated as an effective duel colorimetric sensing for selective and sensitive recognition of Cu2+ and S2−, which could be used to detect these ions with naked eyes. In addition, the possible sensing mechanism was that Cu2+ ions caused serious aggregation of carrageenan-AgNPs, which led to the color change of carrageenan-AgNPs. AgNPs were etched by S2− forming Ag2S, which played an important role in the determination of S2− ions. Furthermore, it has been successfully applied to the determination of Cu2+ and S2− in tap water and lake water, showing its great potential for the analysis of environmental water samples.

Polycystic ovarian, or stein leventhal, syndrome (PCOS) is an inflammatory disorder resulting in metabolic dysregulation and ovarian dysfunction as well as women's infertility. Management of PCOS requires multiple approaches. This experimental study was sought to assess the influence of m (CZ) derived silver particles (AgNPs) on inflammatory cytokines in rats with PCOS. In this experimental study, AgNPs were synthesized using CZ bark extract, and characterized by the scanning electron microscope (SEM) and atomic force microscope (AFM). Thirty female rats, rattus norvegicus, were grouped into five groups (6 animals/group). The experimental groups were vehicle control group (received 0.2 ml corn oil only), PCOS (received estradiol valerate of 4 mg/kg only), PCOS group received CZ extract (200 mg/kg), PCOS group received metformin (50 mg/kg) and PCOS group received AgNPs (3.53 mg/kg). After 30 days of treatment, serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukins-18 (IL-18), and 6 (IL-6) were measured using ELISA. Significant elevation (P<0.05) was noted in TNF-α, IL-6, and IL-18 levels of the PCOS group when compared with findings in the control group (TNF-α: 250.4 ± 32.5 vs. 164.3 ± 34.4 ng/L, IL-6: 169.8 ± 9.4 vs. 77.0 ± 9.3 pg/ml, and IL-18: 45.9 ± 5.5 vs. 35.3 ± 4.1 ng/L). Importantly, AgNPs decreased all three inflammatory biomarkers in the treated group when compared with the PCOS group (TNF-α: 173.9 ± 31.2 vs. 250.4 ± 32.5 ng/L, IL-6: 133.7 ± 9.3 vs. 169.8 ± 9.4 pg/ml, and IL-18: 36.1 ± 6.2 vs. 45.9 ± 5.5 ng/L). CZ-derived AgNPs may have an anti-inflammatory effect in PCOS rats by decreasing the concentrations of inflammatory cytokines TNF-α, IL-6 and IL-18.

The massive use of silver nanoparticles (AgNPs) is potentially harmful to exposed humans. Although previous studies have found that AgNPs can induce cell autophagy, few studies have focused on the toxic pathways and mechanisms of autophagy induced by AgNPs in rat respiratory epithelial (RTE) cells. In this study, RTE cells were exposed to two kinds of AgNPs in vitro to ascertain the influence of mTOR-autophagy pathway-associated protein expression, including Beclin1, LC3B, Atg5, and Atg7. After exposure to different sizes and concentrations of AgNPs for 12 h, the uptake of silver in RTE cells reached 0.45 μg/L to 1.11 μg/L, indicating that AgNPs can enter RTE cells, leading to toxic effects. Our study found that this toxic effect was related to autophagy caused by ROS accumulation that was mediated by the mTOR pathway. With increasing AgNP exposure concentrations, the expression of p-mTOR was significantly downregulated, and expression of the autophagy-related proteins Beclin1, LC3B, Atg5, and Atg7 was significantly increased in RTE cells in all exposed groups. At a concentration of 1000 μg/L, the expression of LC3BII/LC3BI in all exposed groups was 24.49 times and 12.71 times that of the control, and the expression of Atg7 in all exposed groups was 23.21 times and 13.21 times that of the control. The upregulation of autophagy-related proteins in the AgNP-10 nm exposure groups was greater than that of the AgNP-100 nm exposure group. In summary, the mTOR pathway mediates AgNP-induced autophagy in RTE cells, which leads to damage to the respiratory system barrier and human health risks. This study can facilitate the development of prevention and intervention policies against adverse consequences induced by AgNPs.

Nowadays, the researchers search in their studies for new antimicrobial agents which have the unique physical and chemical properties. In this experiment, AgNPs solution was synthesized by chemical reduction, characterized and tested as the antibacterial effects of sliver nanoparticles (Ag-Nps ) on S. aureus. Sliver nanoparticles revealed unique physical and chemical properties that suitable to understand to possess a broad spectrum of antimicrobial activities. Sliver nanoparticles (AgNPs ) characterized by UV- Visible spectrphotometry by exhibiting the typical surface plasmon absorption maxima at 400 nm. The morphology of the sliver nanoparticles was measured by Scanning Electron Microscope (SEM. (Investigating Antimicrobial activity of nanoparticles were evaluated by using Minimum Inhibitory Concentration ( MIC) technique. The experiment results showed that the lowest MIC and MBC of Ag-NPs to S. aureus was 30 ppm, 300ppm, respectively. The obtained results suggested that Ag-NPs exhibit bacteriostatic and bacteriocidal effect towards S.aureus.The present study indicates (AgNps) has considerable antibacterial activity.

Background: In the past years, saprophytic bacteria and candida have been emerging as potential human pathogens causing life-threatening infections in patients with cancer. This study was designed to determine the bacteria and candida species, causing bloodstream infections in cancer patients and the assessment of their susceptibility to antibiotics and biosynthesised silver nanoparticles. Materials and Methods: Ninety-seven microbial pathogens recovered from blood samples of cancer patients were included in the present study. The microbial isolates were collected in a duration period extending from December 2016 to July 2018 at National Cancer Institute, Cairo, Egypt. The clinical samples were collected using microbiological methods and were cultivated on MacConkey agar, blood agar media and Sabouraud dextrose agar media. The microbial isolates were identified using both standard microbiological methods and VITEK 2 compact automated system. The antibiotic resistance pattern was determined by the VITEK 2 compact automatic system and disk diffusion method, according to the Clinical and Laboratory Standards Institute. The characterisation of nanoparticles was carried out using ultraviolet spectroscopy and electron microscope. The antimicrobial activity of bio (AgNPs) was evaluated. Results: A total of 97 microbial isolates recovered from collected blood samples from cancer patients were included in the study. Pathogenic bacteria and Candida were represented by 74 isolates (76.22%) and 23 isolates (23.69), respectively. Among the 74 bacterial isolates, Escherichia coli constituted (27.81%), Klebsiella pneumoniae (24.72%), Acinetobacter baummannii (11.33%), Pseudomonas aeruginosa (4.12%), Enterobacter spp. (3.09%) and) Staphylococcus aureus (2.06%). Cedecea davisae (1.03%), Burkholderia cepacia (1.03%) and Pantoea agglomerans (1.03%). Among the 23 Candida isolates, Candida tropicalis constituted (9.27%), Candida albicans (5.15%), Candida glabrata (5.15%) and Candida krusei (4.12%) from the total microbial isolates . The antibiotic susceptibility results revealed that amikacin and gentamycin were the most effective antibiotics against Gram-negative bacteria, while vancomycin and linezolid were most effective against S. aureus. Caspofungin was the most effective against candida species. The obtained stable biosynthesised silver nanoparticles ranged in size from 10 nm to 100 nm and were mostly spherical in shape. These biosilver nanoparticles showed the highest antimicrobial activity against most of the microbial isolates (bacteria and Candida). The in vitro cytotoxicity of biosynthesised AgNPs on HeLa cell lines revealed a dose-dependent potential. The IC50 value of AgNPs was found 6 and 5.6 μg/ml, respectively. Conclusion: The present study revealed a significant distribution of multidrug-resistant microbes, which may increase the burden of healthcare to prevent infections in cancer patients. Biosilver nanoparticles exhibit antimicrobial activity against multidrug-resistant microbes and could be considered as effective agents against these strains.

The current work describes a biological method to create silver nanoparticles (AgNPs) using jojoba oil. As a reducing and capping agent, jojoba oil was utilized in the production of AgNPs. AgNPs may be classified by their UV-VIS, FTIR, and spectra. A transmission electron microscope (TEM) was used to examine the shape and size of the silver nanoparticles. The average size of the synthesized silver nanoparticles was 25.6 ± 10.3 nm, and they had a spherical shape. According to FTIR spectroscopy tests, the silver nanoparticles' surface had organic molecules bound to it. Five bacterial isolates were isolated and tested for pathogenicity on potatoes. All isolates produced the typical symptoms of soft rot disease. Isolate Pcc2 caused the highest disease severity (45%). According to 16sRNA, isolate Pcc2 was identified as Pectobacterium carotovorum subsp. carotovorum. Increasing the dosage of AgNPs increased the antibacterial effect against P. carotovorum. From these results, we can conclude that the use of AgNPs is a safe method for controlling postharvest potato diseases caused by Pectobacterium carotovorum subsp. carotovorum.

This study presented a novel antimicrobial packaging PVA/xanthan gum film decorated with green-synthesized silver nanoparticles (AgNPs) derived from Myrica rubra leaf extract (MRLE) for the first time. Montmorillonite (MMT) was used to improve its dispersion (AgNPs@MMT). The synthesis time, temperature, and concentration of AgNO3 were considered using a central composite design coupled with response surface methodology to obtain the optimum AgNPs (2 h, 75 °C, 2 mM). Analysis of substance concentration changes confirmed that the higher phenolic and flavonoid content in MRLE acted as reducing agents and stabilizers in AgNP synthesis, participating in the reaction rather than adsorbing to nanoparticles. TEM, XRD, and FTIR images revealed a spherical shape of the prepared AgNPs, with an average diameter of 8.23 ± 4.27 nm. The incorporation of AgNPs@MMT significantly enhanced the mechanical properties of the films, with the elongation at break and shear strength increasing by 65.19% and 52.10%, respectively, for the PAM2 sample. The films exhibited strong antimicrobial activity against both Escherichia coli (18.56 mm) and Staphylococcus aureus (20.73 mm). The films demonstrated effective food preservation capabilities, significantly reducing weight loss and extending the shelf life of packaged grapes and bananas. Molecular dynamics simulations reveal the diffusion behavior of AgNPs in different matrices, while the measured silver migration (0.25 ± 0.03 mg/kg) complied with EFSA regulations (10 mg/kg), confirming its food safety. These results demonstrate the film’s potential as an active packaging material for fruit preservation.