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In this research, silver nanoparticles (AgNPs) were prepared via a 'green' procedure using an aqueous extract of Handelia trichophylla. The formation of AgNPs was confirmed by its light brown colour. The AgNPs were formed in silver nitrate (1 mM) via a bioreduction process in spherically shaped NPs with a mean diameter in the range of 20–50 nm. Moreover, the green synthesized AgNPs seemed to demonstrate a higher antibacterial activity against human pathogenic bacteria. In addition, the in vitro cytotoxicity effect of biosynthesized AgNPs was also investigated, which was detected to be up to 15.62 μg ml–1 in the treated Neuro2A cells. Low toxicity and high antibacterial activity of biosynthesized silver nanoparticles can be utilized in different biological, biomedical and industrial applications. [ABSTRACT FROM AUTHOR]

Objective(s): A simple and "green" method was developed for preparing zinc oxide nanoparticles (ZnO-NPs) in aqueous starch solutions. Starch was used as a stabilizer to control of the mobility of zinc cations and then control growth of ZnO-NPs prepared via a sol-gel method. Because of the special structure of the starch, it permits termination of the particle growth. Materials and Methods: The dried gel was calcined at different temperatures of 400, 500, 600, and 700 °C. The prepared ZnO-NPs were characterized by different techniques such as X-ray diffraction analysis (XRD), transmittance electron microscopy (TEM), and UV-Vis absorption. Results: The XRD results displayed hexagonal (wurtzite) crystalline structure for prepared ZnO nanoparticles with mean sizes below than 50 nm. In vitro cytotoxicity studies on neuro2A cells showed a dose dependent toxicity with non-toxic effect of concentration below 6 μg/mL. Conclusion: The results showed that starch is an eco-friendly material that can be used as a stabilizing agent in the sol-gel technique for preparing of ZnO-NPs in a large scale. [ABSTRACT FROM AUTHOR]

Pre-concentration and determination of Zn (II) across a ligand assisted pseudo stirbar hollow fiber solid/liquid phase microextraction method in water samples has been investigated. All detections were carried out by differential pulse anodic stripping voltammetry (DPASV). The method involves microextraction and pre-concentration of Zn (II) on the pseudo stir bar hollow fiber. Then desorption has been done using suitable solvent containing suitable ligand as complexing agent. The optimized conditions were obtained. The relationship between the peak current and concentration was linear over the range of 0.05–500 ng mL −1 . The limit of detection was 0.015 ng mL −1 . Under the optimized conditions, the pre-concentration factor is 5140. The applicability of the developed technique was evaluated by application to spiked, environmental water samples. [ABSTRACT FROM AUTHOR]

Development of light-harvesting properties and inhibition of photogenerated charge carrier recombination are of paramount significance in the photocatalytic process. In the present work, we described the synthesis of core-shell heterostructures, which are composed of titanium oxide (TiO 2 ) and cerium oxide (CeO 2 ) deposited on a reduced graphene oxide (rGO) surface as a conductive substrate. Following the synthesis of ternary rGO-CeO 2 @TiO 2 and rGO-TiO 2 @CeO 2 nanostructures, their photocatalytic activity was investigated toward the degradation of rhodamine B dye as an organic pollutant under UV light irradiation. The obtained structures were characterized with high-resolution transmission electron microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy surface analysis, and UV-Vis spectroscopy. Various parameters including pH, catalyst dosage, temperature, and contact time were studied for photocatalysis optimization. Heterostructures showed considerable advantages because of their high surface area and superior photocatalytic performance. In contrast, rGO-CeO 2 @TiO 2 showed the highest photocatalytic activity, which is attributed to the more effective electron-hole separation and quick suppression of charge recombination at core-shell phases. A biological assay of the prepared heterostructure was performed to determine the cytotoxicity against breast cancer cells (MCF-7) and demonstrated a very low survival rate at 7.65% of cells at the 17.5 mg mL -1 concentration of applied photocatalyst., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)