Environmentally green synthesis of stable polyvinyl pyrrolidone (PVP)-capped silver nanoparticles (PVP-AgNPs) was successfully carried out. The present study focused on investigating the influence of adding PVP during the synthesis process on the size, optical properties and antibacterial effect of silver nanoparticles produced. An aqueous extract of Eucalyptus camaldulensis leaves was used as a reducing agent. The effects of different PVP concentrations and reducing time on the synthesis of nanoparticles (NPs) were characterized by UV–Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive spectrum (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and nano tracker analysis (NTA). The addition of PVP was studied. The prepared PVP-AgNPs were spherical with an average size of 13 nm. FTIR analysis confirmed that PVP protects AgNPs by a coordination bond between silver nanoparticles and both N and O of PVP. DLS results indicated the good dispersion of silver nanoparticles. PVP-AgNPs were found to be stable for nearly 5 months. Antibacterial studies through the agar well diffusion method confirmed that silver nanoparticles synthesized using PVP had no inhibitor activity toward Gram-positive and Gram-negative bacteria as opposed to silver nanoparticles prepared without adding PVP, which showed a significant antibacterial activity towards some of the tested pathogens.
In the current study, we investigated the anticancer potential against human colon cells (Caco-2) of colloidal nanosilver (CN–Ag) produced in Syria using bioactive compounds in the aqueous extract of Eucalyptus camaldulensis leaves (AEECL). The formation of AgNPs was confirmed by UV-visible spectroscopy analysis with surface plasmon peak at 449 nm and their average size was found to be 12, 10, 23 nm by SEM, DLS and NTA respectively. This small size has confirmed the effective role of AEECL as capping agent. Further morphological characterization was done by EDS showed the presence of metallic silver. Zeta potential value (-23 mV) indicated the repulsion among the particles and stability of the formulation nanosilver. The anticancer effect of synthesized CN–Ag against Caco-2 has been tested. The cytotoxicity assay showed a dose-dependent and a time-dependent effect of CN–Ag. The high cytotoxicity of CN–Ag at low concentration (5μ/mL) open new prospects for the development of novel therapeutic approaches against human colon cancer Caco-2.
24 February 2020 in Inorganic and Nano-Metal Chemistry
This study is one of the few studies that presents an ecofriendly procedure for biosynthesis of AgNPs via aqueous extract Eucalyptus camaldulensis leaves (AEECL). The main of current work was to ensure the ability of AEECL as reducing agent for synthesis of AgNPs. Characterization of AgNPs was carried out by UV-Vis, FTIR and XRD, SEM, EDX, DLS, and Zeta value. The surface Plasmon at 450 nm is the primary confirmation for the formation of Ag. Characterization studies by SEM found the synthesized AgNPs were spherical shape with size about 28 nm. The EDX analysis of the AgNPs confirmed strong signals for silver atoms. According XRD analysis, synthesis of Silver nanocrystals with size ∼16 nm was confirmed. The FT-IR study confirmed that the ECL extract acts both role as a reducing agent and a stabilizer of AgNPs. The DLS results confirmed the monodispersity of AgNPs with mean size of 68 nm.
In this paper, zinc sulfide nanoparticle (ZnS-NP) thin films were deposited onto glass substrates by chemical bath deposition using zinc sulfate as the cation precursor and thiourea as the anionic precursor. Different bath temperatures (65, 70, 75, and 80°C) and different deposition times (20, 30, 40, and 50 min) were selected to study the performance of ZnS thin films. Topographical and optical characterizations of the films were studied using the atomic force microscope (AFM) and UV-Vis spectroscope. The best ZnS thin films were deposited at a bath temperature (70°C) and a deposition time (30 min) with homogeneous distribution, high density, and small average diameter (106 nm). The energy gap () was found to be in the range of 4.05-3.97 eV for the ZnS films. Optical constants (refractive index, , extinction coefficient, , and dielectric constant, ) of the films were obtained in the wavelength range 300-500 nm by using spectrophotometric measurement. The dispersion of the refractive index is analyzed by using a single oscillator model. The oscillator energy and dispersion energy were determined using the Wemple-DiDomenico single oscillator model. Urbach’s energy increases from 0.907 eV to 2.422 eV with increasing of deposition time. The calculated radius of nanoparticles using Brus equation was 1.9, 2.3, 2.45, and 2.51 nm at deposition times 20, 30, 40, and 50 min, respectively.
Achieving food security stands as a primary challenge confronting global societies today. This necessitates the development of effective strategies to increase crop productivity and enhance their specifications, aiming to meet the growing market demands sustainably and efficiently. This research was conducted over two agricultural seasons and emphasizes the ability of silver nanoparticles (AgNPs) to promote the growth and productivity of durum wheat (variety Sham 7) cultivated under the conservative conditions of Deir ez‐Zor. The wheat seeds were soaked before planting with a colloidal suspension of AgNPs, prepared through an eco‐friendly method utilizing an aqueous extract of Eucalyptus camaldulensis leaves. The best plant morphological indicators (plant height, chlorophyl content, number of branches, and number of spikes) were observed when colloidal AgNPs were used as a soaking solution compared with silver nitrate (AgNO 3 )and deionized (DI) water as a control. The highest productivity parameters (grain yield, straw yield, and 1000‐grain weight) were obtained when seeds were soaked in 40 ppm of AgNPs. Furthermore, the results revealed an increase in the nutrient content of grain (nitrogen, phosphorus, and potassium). This study offers valuable insights into the prospective use of AgNPs for significant improvement in wheat cultivation, increasing productivity, and improving crop quality. As a contribution to facing future challenges in the field of agriculture and ensuring sustainable food security.
Leishmaniasis is one of the biggest health problems in the world. Traditional therapeutic methods still depend on a small range of products, mostly chemically. However, the treatment with these drugs is expensive and can cause serious adverse effects, and they have inconsistent effectiveness due to the resistance of parasites to these drugs. The treatment of leishmanial disease has always been a challenge for researchers. The development of nanoscale metals such as silver has attracted significant attention in the field of medicine. The unique characteristic features of silver nanoparticles (AgNPs) make them effective antileishmanial agents. In recent years, green nanotechnology has provided the development of green nanoparticle-based treatment methods for Leishmaniasis. Although there are many studies based on green nanoparticles against Leishmania parasites, this is the first study on the antileishmanial effect of biosynthesized AgNPs using an aqueous extract of Eucalyptus camaldulensis leaves (AEECL) as a reducing agent of silver ions. Different parameters such as AgNO3 concentration, AEECL concentration, and reaction time were studied to investigate the optimum factors for the preparation of stable and small-sized silver nanoparticles. The spherical shape of colloidal nanosilver (CN-Ag) was confirmed by atomic force microscope (AFM) and scanning electron microscope (SEM) images with sizes of 27 and 12 nm, respectively. A high density of nanoparticles with a small size of 10 nm has been confirmed from dynamic light scattering (DLS) analysis. The zeta potential value of 23 mV indicated that colloidal silver nanoparticles were stable. The nano-tracker analysis (NTA) showed the Brownian motion of silver nanoparticles with a hydrodynamic diameter of 31 nm. The antioxidant property of CN-Ag was determined using the stable radical 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. In this study, a significant cytotoxic effect of biosynthesized CN-Ag has been shown against Leishmania tropica parasites at low concentrations (1.25, 2.5, and 3.75 µg/mL). These results could be used as a future alternative drug or could be a supportive treatment for Leishmaniasis.