Manal Ahmed Gasmelseed Awad

Silver nanoparticles biogenic synthesized using an orange peel extract and their use as an anti-bacterial agent

Synthesis of nanoparticles by green methods with antibacterial properties is of great researchers’ concern in the explored of new pharmaceutical and biomedical products. In this study, we synthesized a new product of nanosized particles of silver, non-toxic economy, clean, and conservator for energy. An environmentally friendly route is used for synthesizing silver nanoparticles (AgNPs) using an orange peel extract as both reducing and stabilizing agent at room temperature. The synthesized NPs were characterized using ultraviolet (UV)-Vis spectrophotometer, Zitasizer which measures the average size of the particles at about 91 nm, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) equipped with the energy dispersive spectroscopy (EDS) and characterization using Transmission electron microscopy (TEM). The results confirmed that the orange peel extract is a very good bioreductant for the synthesis of Ag NPs and we investigated the synthesized nanoparticles as an antibacterial which showed that the biogenic synthesized AgNPs exhibit inhibition, and had significant antibacterial against both gram-positive and gram-negative bacterial strains. Key words: Silver nanoparticles, biogenic synthesis, orange peel, anti bacterial, gram-positive, gram-negative bacteria streamers.

Green synthesis, characterization, and antibacterial activity of silver/polystyrene nanocomposite

A novel, nontoxic, simple, cost-effective and ecofriendly technique was used to synthesize green silver nanoparticles (AgNPs). The AgNPs were synthesized using orange peel extract as a reducing agent for silver nitrate salt (AgNO3). The particle size distribution of AgNPs was determined by Dynamic Light Scattering (DLS). The average size of silver nanoparticles was 98.43 nm. The stable dispersion of silver nanoparticles was added slowly to polystyrene solution in toluene maintaining the temperature at 70°C. The AgNPs/polystyrene (PS) nanocomposite solution was cast in a petri dish. The silver nanoparticles encapsulated within polymer chains were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) equipped with Energy Dispersive Spectroscopy (EDS) in addition to Transmission Electron Microscopy (TEM). The green AgNPs/PS nanocomposite film exhibited antimicrobial activity against Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae and Salmonella, and Gram-positive bacteria Staphylococcus aureus. Thus, the key findings of the work include the use of a safe and simple AgNPs/PS nanocomposite which had a marked antibacterial activity which has a potential application in food packaging.

Clinical Efficacy Associated with Enhanced Antioxidant Enzyme Activities of Silver Nanoparticles Biosynthesized Using Moringa oleifera Leaf Extract, Against Cutaneous Leishmaniasis in a Murine Model of Leishmania major

Leishmaniasis is one of the most significant vector-borne syndromes of individuals. This parasitic infection can be affected by many species of Leishmania, most of which are zoonotic. Natural products have made and are continuing to make important contributions to the search for new antileishmanial agents. The use of plants in the production assembly of silver nanoparticles has drawn attention because of its rapid, eco-friendly, non-pathogenic, economical protocol and provides a single step technique for the biosynthetic process. Hence, we aimed to biosynthesize silver nanoparticles (Ag-NPs) using Moringa oleifera leaf extract and investigated the antileishmanial activity of these nanoparticles in a murine model of Leishmania major infection. A total of 50 mice were used and divided into five groups—healthy control, infected, infected mice treated with pentostam, infected mice treated with Ag-NPs and infected mice pretreated with Ag-NPs. In the present study, the leaf extract of the plant species Moringa oleifera was found to be a good source for the synthesis of silver nanoparticles, their formation being confirmed by color change and stability in solution. In the present murine model of Leishmania major infection, we found that oral treatment with silver nanoparticles biosynthesized using Moringa oleifera extract resulted in a significant reduction in the average size of leishmaniasis cutaneous lesions compared with untreated mice. Furthermore, the clinical efficacy of Moringa oleifera extract was associated with enhanced antioxidant enzyme activities. In conclusion, treatment with silver nanoparticles biosynthesized using Moringa oleifera extract has higher and faster clinical efficacy than standard pentavalent antimonial treatment, probably by boosting the endogenous antioxidant activity.