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The current study proposed a novel simple and environmentally friendly approach for producing silver nanoparticles (AgNPs) using an extract of Moringa oleifera leaves (MOL) and optimizing the different experimental factors required for the formation and stability of AgNPs. The formation of nanoparticles was confirmed by a color change from yellow to reddish-brown with a surface plasmon resonance band at 412 nm. The morphology, size, and elemental composition of AgNPs were investigated by zeta potential dynamic light scattering, field emission scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, and transmission electron microscopy analysis, which showed crystalline and spherical AgNPs. The identification of functional groups was supported by Fourier-transform infrared spectroscopy. The photocatalytic activities of AgNPs were assessed in the degradation of organic Malachite green (MG) dye in the aqueous solution. Two kinetic adsorption models, the pseudo-first-order model and the pseudo-second-order model, and three isotherm models, the Langmuir, Freundlich, and Temkin, were used to mathematically characterize the MG degradation process. The pseudo-second-order kinetics and the Freundlich isotherm model were found to be in good agreement with the experimental data. As a result of their synergistic interaction with the MOL extract solution, the photocatalytic activity of AgNPs increases and they can successfully adapt to the photodegradation of organic dyes in industrial effluents.

Solanum nigrum and Mentha leaf extracts were used as reducing and stabilizing reagents in the green synthesis of silver oxide nanoparticles (AgO NPs), and their antibacterial efficacy was subsequently evaluated. The structure and morphology of AgO NPs were evaluated using X-ray diffraction and filed emission scanning electron microscope. High-resolution transmission electron microscopy images were used to analyze the characteristics of certain particles with clearly discernible atomic structures. The functional group and elemental composition of AgO NPs were investigated using fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy. Ultraviolet–visible spectroscopy was used to determine the energy band gap (E g) of the sample. The dielectric constant of both samples was found to be inversely proportional to frequency, whereas the dielectric loss was found to be directly proportional to temperature but directly proportional to frequency. This suggests that the space charge has an effect on the mechanism of charge transfer as well as polarizability. AC conductivity rises and is inversely proportional to temperature increases. AgO NPs had a size range of around 56 nm and were mostly spherical. The antibacterial potential of the synthesized AgO NPs using both extracts was compared by the well-diffusion method. AgO NPs at 50–100 µg·mL−1 concentration significantly inhibited the bacterial growth of Bacillus cereus, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumonia.

Bioactive plant chemicals are considered to be rich and useful for creating nanomaterials. The current work investigated the biosynthesis of silver nanoparticles (AgNPs) using ethanolic flaxseed extract as an efficient reducing factor. The production of AgNPs was verified by color-shifting observation of the mixture of silver nitrate (AgNO3) from yellow to a reddish suspension after the addition of the extract and by evaluating it by UV–visible inspection. Additionally, FTIR spectrum was used to support the identification of functional groups. The morphology and structure of AgNPs were assessed using scanning electron microscopy (SEM), and X-ray diffraction (XRD) examinations, which revealed spherical AgNPs with a diameter of 46.98 ± 12.45 nm and a crystalline structure. The zeta potential (ZP) and dynamic light scattering (DLS) measurements of AgNPs revealed values of −44.5 mV and 231.8 nm, respectively, suggesting appropriate physical stability. The antibacterial activity of AgNPs was investigated against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes, while the antioxidant effect was investigated using the DPPH technique. These obtained AgNPs could potentially be used as efficient antibacterial and antioxidant nanomaterials. [ABSTRACT FROM AUTHOR]

The current work concentrated on the green synthesis of silver nanoparticles (AgNPs) through the use of aqueous Citruslimon zest extract, optimizing the different experimental factors required for the formation and stability of AgNPs. The preparation of nanoparticles was confirmed by the observation of the color change of the mixture of silver nitrate, after the addition of the plant extract, from yellow to a reddish-brown colloidal suspension and was established by detecting the surface plasmon resonance band at 535.5 nm, utilizing UV-Visible analysis. The optimum conditions were found to be 1 mM of silver nitrate concentration, a 1:9 ratio extract of the mixture, and a 4 h incubation period. Fourier transform infrared spectroscopy spectrum indicated that the phytochemicals compounds present in Citrus limon zest extract had a fundamental effect on the production of AgNPs as a bio-reducing agent. The morphology, size, and elemental composition of AgNPs were investigated by zeta potential (ZP), dynamic light scattering (DLS), SEM, EDX, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analysis, which showed crystalline spherical silver nanoparticles. In addition, the antimicrobial and antioxidant properties of this bioactive silver nanoparticle were also investigated. The AgNPs showed excellent antibacterial activity against one Gram-negative pathogens bacteria, Escherichia coli, and one Gram-positive bacteria, Staphylococcus aureus, as well as antifungal activity against Candida albicans. The obtained results indicate that the antioxidant activity of this nanoparticle is significant. This bioactive silver nanoparticle can be used in biomedical and pharmacological fields. [ABSTRACT FROM AUTHOR]

This paper describes the preparation, characterization, and evaluation of honey/tripolyphosphate (TPP)/chitosan (HTCs) nanofibers loaded with capsaicin derived from the natural extract of hot pepper (Capsicum annuumL.) and loaded with gold nanoparticles (AuNPs) as biocompatible antimicrobial nanofibrous wound bandages in topical skin treatments. The capsaicin and AuNPs were packed within HTCs in HTCs-capsaicin, HTCs-AuNP, and HTCs-AuNPs/capsaicin nanofibrous mats. In vitro antibacterial testing against Pasteurella multocida, Klebsiella rhinoscleromatis,Staphylococcus pyogenes, and Vibrio vulnificus was conducted in comparison with difloxacin and chloramphenicol antibiotics. Cell viability and proliferation of the developed nanofibers were evaluated using an MTT assay. Finally, in vivo study of the wound-closure process was performed on New Zealand white rabbits. The results indicate that HTCs-capsaicin and HTCs-AuNPs are suitable in inhibiting bacterial growth compared with HTCs and HTCs-capsaicin/AuNP nanofibers and antibiotics (P < 0.01). The MTT assay demonstrates that the nanofibrous mats increased cell proliferation compared with the untreated control (P < 0.01). In vivo results show that the developed mats enhanced the wound-closure rate more effectively than the control samples. The novel nanofibrous wound dressings provide a relatively rapid and efficacious wound-healing ability, making the obtained nanofibers promising candidates for the development of improved bandage materials. [ABSTRACT FROM AUTHOR]