Search

This paper presents a facile, and ecofriendly method to prepare colloidal silver nanoparticles (AgNPs) at room temperature using bulk silver bars, bi-distilled water, trisodium citrate, and a direct-current voltage source. AgNP formation was confirmed and characterized by ultraviolet–visible spectroscopy, transmission electron microscopy and X-ray diffraction. Their antibacterial activity was examined by disc diffusion and minimum inhibitory concentration (MIC) techniques against three bacterial strains, including the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa . Results showed that the size of AgNPs formed was about 19.7±4.3 nm with nearly spherical shape and high purity. The antibacterial activity of as-prepared AgNPs was determined through zones of inhibition against the growth of three bacterial strains on agar. MIC analysis showed that S. aureus had resistance to AgNPs that was about 2–3 times higher than those of E. coli and P. aeruginosa , and that resistance ability depended on the bacterial concentrations inoculated. This work revealed the effective method of synthesizing a large quantity of colloidal AgNPs with high antibacterial effectiveness and potential application in different fields. [ABSTRACT FROM AUTHOR]

• AgNPs were green synthesized using leaf extracts of P. boldus and incorporated into an nPSi structure by capillary suction. • Composite thin films of nPSi/AgNPs were chemically and morphologically characterized. • Antibacterial activity of nPSi/AgNPs layers was successfully evaluated using a wide fan of bacterial strains. This work is about the fabrication of composite thin films of nanoporous silicon/green synthesized silver nanoparticles and their potential use as antibacterial surfaces. To obtain the composite layers, silver nanoparticles were synthesized using leaf extracts of P. boldus , and subsequently integrated on nanoporous silicon matrix. The achieved samples were characterized microscopically (TEM and AFM), and physiochemically (UV–vis spectroscopy, LIBS, and XRD). Moreover, the antibacterial activity of the composite layers was studied using different strains of Gram-positive (S. aureus and S. epidermidis) and Gram-negative (K. pneumoniae , E. coli , and P. aeruginosa) bacteria. The experimental results showed the potential of these composite thin films as antibacterial surfaces for biomedical applications. [ABSTRACT FROM AUTHOR]

In the present study, silver nanoparticles (AgNPs) were synthesized by using aqueous leaves extract of Skimmia laureola at room temperature. The color change in reaction mixture (pale yellow to dark brown) was observed during synthesis process. Biosynthesized silver nanoparticles showed surface Plasmon resonance at around 460 nm. The spherical and hexagonal shapes and crystalline nature of silver nanoparticles were confirmed by SEM and XRD analysis. The bioactive chemicals constituent of leaf extract of S. laureola such as tritepenoid s , skimmidiol and coumarins, were mainly involved in the synthesis of silver nanoparticles. Furthermore, antibacterial potential of aqueous extract of S. laureola leaf and biosynthesized silver nanoparticles found to be potent agent against tested human pathogens and it is suitable nanomaterial for biomedical application. [ABSTRACT FROM AUTHOR]

[Display omitted] • AgNPs were facile synthesized from Glochidion candolleanum leaf (GCL) extract. • FT-IR, FE-SEM, and TEM analyses confirmed the properties of AgNPs. • GCL·AgNPs exhibited antimicrobial activity against G+ve and G−ve bacteria. • GC–MS revealed the presence of antimicrobial phytochemicals in GCL extract. In the present study, Glochidion candolleanum (Wight & Arn.) Chakrab. & M. Gangop. leaf (GCL)-ethyl acetate extract was used for the phytosynthesis of silver nanoparticles (AgNPs) and subjected to antibacterial assay with G+ve and G−ve bacteria. The GCL·AgNPs synthesized were characterized through various spectroscopic and microscopic analyses, while the phytochemical compounds was analyzed by GC–MS. The discrete GCL·AgNPs formed were micron-scale range. TEM images of AgNPs reveal that nanoparticles were spherical and ellipsoidal in shape, dispersed uniformly and capped with secondary material of ≈10 nm thickness. A maximum inhibition zone of 12.2 mm diameter was observed against Salmonella enterica followed by 11.8 mm diameter against Pseudomonas aeruginosa. GC–MS analysis revealed the occurrence of bioactive phytocompounds in GCL extract, hexamethylcyclotrisiloxane, 2,4,6-cycloheptatrien, benzenepropanoic acid, 2-ethylacridine, benzo[h]quinoline, methyltris(trimethylsiloxy)silane and 5-methyl-2-phenylindolizine. The findings suggest that GCL could be used for developing antibacterial AgNPs against pathogenic bacteria. [ABSTRACT FROM AUTHOR]