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In this work, a novel and versatile route was developed, using Latex copolymer to synthesize pure and silver doped mesoporous Ag/TiO2 (MNps) with various silver contents using two-stage processing method. We investigated the influence of both silver doping content and calcination temperature on the physical features and photocatalytic responses of Ag/TiO2. The Ag/TiO2 nanostructures were characterized using multiple analytical techniques like Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive analysis Scope (EDS), X-Ray Diffraction (XRD), and ultraviolet-visible spectroscopy (UV-Vis). The results indicated that mesoporous Ag/TiO2 are obtained in the form of core-shell structured Nps, Where TiO2 nanoparticles (NPs) had a perfect spherical morphology at 400°C, with a size range of 50 to 300 nm, assembled in an orderly manner with primary nano crystallites of silver on the surface with an average size varying from 5 to 10 nm, forming a. The XRD measurements reported the presence of Anatase TiO2 phase and silver nanoparticles. Photocatalytic studies were carried out in model solutions of water and Methylene Blue (MB) dyes under visible irradiation in presence of pure and metal doped mesoporous Ag/TiO2 (MNps). The samples show a sequential combination of adsorption and photocatalytic dye degradation process with variable reaction rate constants depending on the content of doping silver element. Almost 95% removal of methylene blue was achieved using 5 - 7.5% Ag/TiO2 as a photocatalyst; with a combination of 60% dye adsorption and 35% dye photocatalytic degradation after 60 min of under visible light irradiations. [ABSTRACT FROM AUTHOR]

This study reports the green synthesis and characterization of silver nanoparticles (AgNPs) assisted with Cedrela odorata extracts and their antifungal efficacy against Fusarium circinatum, one of the most threatening pathogens in forest nurseries. Various extract volumes (1, 3, and 5 mL) of leaf and the bark of red cedar were tested. The nanoparticles were characterized using UV-Vis spectroscopy, transmission electron microscopy, and energy-dispersive spectroscopy of X-rays (EDS-TEM). Phytochemicals in the extracts were explored using Fourier transform infrared spectroscopy (FTIR). The results were analyzed using ANOVA and Tukey's tests with (p ≤ 0.05, 95%). Both leaves and bark extracts produced AgNPs, but the particles from bark extract (AgNPs-B) were smaller (19.80 ± 9.88 nm, λmax at 447 nm), and they were more stable than particles from leaf extract (AgNPs-L) because they showed a superficial plasmon resonance (SPR) over 12 months. Phenols and triterpenoids, associated with -OH, C=O, and –NH, were identified in the plant extracts that could act as reducing and capping agents. The AgNPs exhibited good antifungal activity because the inhibition diameter (11.38 ± 0.8 mm) observed for 800 mg AgNO3 L−1 was statistically similar to the inhibition diameter (10.7 ± 0.7 mm) at lower concentrations of particles (200 mg AgNPs L−1), and benzimidazole showed no fungus inhibition. Hence, it could be concluded that the bark extract performed better than the leaf extract. In conclusion, this study reports a new method for the synthesis of AgNPs assisted with cedar bark that exhibit a good antifungal activity against F. circinatum. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increasing interest in the green synthesis of metallic nanoparticles, mostly because of the evident limitations associated with chemical and physical methods. Green synthesis, commonly referred to as "biogenic synthesis," is seen as an alternative approach to produce AgNPs (silver nanoparticles). The current work focuses on the use of Asterarcys sp. (microalga) for biological reduction of AgNO3 to produce AgNPs. The optimal parameters for the reduction of AgNPs were determined as molarity of 3 mM for AgNO3 and an incubation duration of 24 h at pH 9, using a 20:80 ratio of algal extract to AgNO3. The biosynthesized Ast-AgNPs were characterised using ultraviolet–visible spectroscopy (UV–Vis), zeta potential, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HR-TEM) with selected area electron diffraction (SAED) patterns. The nanoparticles exhibited their highest absorption in the UV–visible spectra at 425 nm. The X-ray diffraction (XRD) investigation indicated the presence of characteristic peaks at certain angles: 38.30° (1 1 1), 44.40° (2 0 0), 64.64° (2 2 0), and 77.59° (3 1 1) according to the JCPDS file No. 04-0783. Based on SEM and TEM, the Ast-AgNPs had an average size of 35 nm and 52 nm, respectively. The zeta potential was determined to be − 20.8 mV, indicating their stability. The highest antibacterial effectiveness is shown against Staphylococcus aureus, with a zone of inhibition of 25.66 ± 1.52 mm at 250 μL/mL conc. of Ast-AgNPs. Likewise, Ast-AgNPs significantly suppressed the growth of Fusarium sp. and Curvularia sp. by 78.22% and 85.05%, respectively, at 150 μL/mL conc. of Ast-AgNPs. In addition, the Ast-AgNPs exhibited significant photocatalytic activity in degrading methylene blue (MB), achieving an 88.59% degradation in 120 min, revealing multiple downstream applications of Ast-AgNPs. [ABSTRACT FROM AUTHOR]

Green synthesis of bioactive nanoparticles (NPs) is getting more attractive in various fields of science including the food industry. This study investigates the green synthesizing and characterization of gold NPs (AuNPs) and silver NPs (AgNPs) produced using Mentha spicata L. (M. spicata) essential oil as well as their antibacterial, antioxidant, and in vitro cytotoxic effects. The essential oil was mixed with both Chloroauric acid (HAuCl4) and aqueous silver nitrate (AgNO3) solutions separately and incubated at room temperature for 24 h. The chemical composition of the essential oil was identified by gas chromatography coupled with a mass spectrometer detector (GC–MS). Au and Ag nanoparticles were characterized using UV–Vis spectroscopy, transmission electron microscopy, scanning electron microscopy, dynamic light scattering (DLS), X-ray diffraction (XRD) and Fourier transform infrared (FTIR). The cytotoxicity of both types of nanoparticles was evaluated using MTT assay on cancerous HEPG-2cell line by exposing them to various concentrations of both NPs for 24 h. The antimicrobial effect was evaluated by the well-diffusion technique. The antioxidant effect was determined by DPPH and ABTS tests. According to the results of GC–MS analysis, 18 components were identified, including carvone (78.76%) and limonene (11.50%). UV–visible spectroscopy showed a strong absorption peak of 563 nm and 485 nm, indicating the formation of Au NPs and Ag NPs, respectively. TEM and DLS demonstrated that AuNPs and AgNPs were predominantly spherical shaped with average sizes of 19.61 nm and 24 nm, respectively. FTIR analysis showed that biologically active compounds such as monoterpenes could assist in the formation and stabilization of both types of NPs. Additionally, XRD provided more accurate results, revealing a nano-metal structure. Silver nanoparticles exhibited better antimicrobial activity against the bacteria than AuNPs. Zones of inhibition ranging 9.0–16.0 mm were recorded for the AgNPs, while zones of 8.0–10.33 mm were observed AuNPs. In the ABTS assay, the AuNPs and AgNPs showed a dose-dependent activity and synthesized nanoparticles exhibited higher antioxidant activity than MSEO in both assays. Mentha spicata essential oil can be successfully used for the green production of Au NPs and Ag NPs. Both green synthesized NPs show antibacterial, antioxidant, and in vitro cytotoxic activity. [ABSTRACT FROM AUTHOR]

Objective: To assess the anticancer potential of biosynthesized silver nanoparticles using marine derived fungi Hamigera pallida with their antibacterial and antioxidant activities. Results: The biosynthesis of silver nanoparticles (AgNPs) was assessed by the change in color from bright yellow to dark brown. UV–Visible spectroscopy revealed its stability at 429 nm; ATR-FTIR spectroscopy revealed the functional group responsible for its production; X-Ray Diffraction revealed its crystalline FCC structure resembling the peaks in the XRD pattern, corresponding to (110), (111), (200), and (311) planes; TEM imaging revealed its spherical morphology with an average particle size of 5.85 ± 0.84 nm ranging from 3.69 to 16.11 nm and Tauc's plot analysis revealed a band gap energy of 2.22 eV, revealing aptitude of AgNPs as a semiconductors. The subsequent characterization results revealed the effective synthesis of silver nanoparticles. The biosynthesized AgNPs were found to have significant antimicrobial effect against three Gram-positive and three Gram-negative bacteria. They also demonstrated higher antioxidative potential by demonstrating strong radical scavenging activity against DPPH (2, 2-diphenyl-1-picrylhydrazyl). AgNPs showed highest anticancer activity (62.69 ± 1.73%) against human breast cancer (MCF-7) cell line at 100 µg/mL with the IC50 value of 66.07 ± 2.17 µg/mL. Conclusions: This study revealed the prospect for further utilization of AgNPs by Cell free filtrate of Hamigera pallida as an antibacterial, antioxidative and anticancer agents. [ABSTRACT FROM AUTHOR]

In this study, low-cost, simple, and eco-friendly green synthesis of silver nanoparticles was performed using pomegranate extract (Ag NPs/PG). Punica granatum extract acts as a reducing agent and capping agent in the synthesis of Ag NPs. The presence of Ag NPs/PG was analyzed using characterization methods such as UV–Vis absorption spectroscopy (UV–Vis), Fourier transform infrared spectrophotometer (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). XRD, TEM, and XPS analysis showed the presence elements, surface morphology, various shapes, and the presence of Ag NPs in the sample. The Ag NPs/PG particle sizes were found to be 5–45 nm in TEM analysis. By using the XRD technique, Ag NPs were determined to be a cubic crystal structure with face-centered. Furthermore, the antioxidant and antibacterial properties of Ag NPs/PG were also investigated. The enhanced biological activity of Punica granatum-mediated green synthesized Ag NPs was investigated based on antioxidant, antimicrobial, and DNA cleavage studies. The Ag NPs showed 91.6% DPPH (2,2-diphenyl-1-picrylhydrazyl) radical inhibition rate activity at the highest concentration (500 mg mL−1). It exhibited significant chemical nuclease activity. Ag NPs/PG had significant antibacterial activity against gram-positive and gram-negative bacteria, but gram-negative bacteria more susceptible than gram-positive. Biogenic synthesis of Ag NPs with the help of Punica granatum extract is a useful and environmentally safe synthesis technique. It is thought that Ag NPs obtained using Punica granatum may have potential use in the fields of nanomedicine, nanobiosensor, and nanobiotechnology in the near future. [ABSTRACT FROM AUTHOR]