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Silver nanoparticles (AgNPs) have been widely studied due to their interesting physicochemical properties and remarkable antibacterial properties. Chemical synthesis methods, including green chemistry, have achieved 0D nanostructures. However, ecological methods have little studied self-assembling Ag nanostructures, such as flowers or dendrites. In this work, Ag dendrites and Ag flower-like morphologies have been successfully synthesized using a one-step green method employing Arctostaphylos pungens Kunth fruit extract at room temperature. The antibacterial properties of both nanostructures were evaluated against Gram-positive Escherichia coli and Gram-negative Staphylococcus aureus bacteria. Scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), and infrared spectroscopy (IR) characterized the synthesized products. The morphological changes of the nanostructures come from the variation in the concentration of the precursor salt, silver nitrate (AgNO3). A growth mechanism is proposed that includes the formation of nanospheres and their subsequent transformation into Ag dendrites. Both nanostructures show good antibacterial activity against the tested microorganisms. The Ag dendritic nanostructures presented inhibition zones of 11 mm and 10.7 mm against Escherichia coli and Staphylococcus aureus bacteria. However, the flower-like structure was slightly less effective, presenting 11 and 9.5 mm inhibition zones against the same microorganisms, respectively. [ABSTRACT FROM AUTHOR]

The synthesis of nanoparticles by biological routes may leads to the development of clean, non-toxic and environmentally acceptable green chemistry procedures. In this context, the present study was aimed to synthesize silver nanoparticles (AgNPs) using the leaf extract of Parthenium hysterophorus and to evaluate its antibacterial and anticancer activity. The synthesized AgNPs were characterized by UV–Vis, FTIR, XRD and TEM. The AgNPs were tested against clinical pathogens viz. Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus and Enterococcus faecalis with the maximum zone of inhibition 18, 19, 13, 17 and 12 mm, respectively at 80 µg/ml concentration. The cytotoxic assay (MTT) of synthesized AgNPs against HepG2 liver cancer cells showed significant inhibition by reducing cell viability below 50% at 53 μg/ml concentration promising the anticancer effect. The wound healing assay was performed to confirm the proliferation of HepG2 cells and the inhibition of growth observed at 50 µg/ml concentration in the 24 h treatment of AgNPs when compared with control. It was eventually concluded that the synthesized AgNPs showed promising antibacterial and anticancer activity against HepG2 liver cancer cells by promoting the inhibition of cell proliferation and migration on very low concentration. [ABSTRACT FROM AUTHOR]

A straightforward and environmentally benign method for the synthesis of silver nanoparticles (AgNPs) is reported in this paper. A sustainable and nontoxic polysaccharide carboxy methyl cellulose (CMC) was used as both reducing agent and stabilizer in the process of synthesizing AgNPs. By varying the precursor concentration, solution pH value, reaction temperature and duration, the highly stable and smaller sized AgNPs with narrow size distribution were obtained. The as-synthesized AgNPs were characterized using UV-Vis absorption spectroscopy, high resolution transmission electron microscopy, X-ray diffraction and zeta potential and size analyzer. Measurements of optical spectra showed that the surface plasmon resonance was localized around 404 nm. The TEM images showed that the particles are well dispersed and spherical in shape with an average particle diameter of 11.64 ± 2.32 nm which is less than the value (13.12 ± 1.54 nm) measured by dynamic light scattering. The zeta potential value of AgNPs was measured to be − 62.8 mV which indicated that CMC coated on the surface of as-synthesized AgNPs resulting in the negatively charged surface and the stable in nature. The prepared silver nanoparticles are effective in inhibiting the growth of both gram positive Staphylococcus aureus and gram negative Escherichia coli. [ABSTRACT FROM AUTHOR]

The green synthesis of silver nanoparticles (AgNPs) has been proposed as a simple, eco-friendly and cost effective alternative to chemical and physical methods. The Rhus chinensis plant is one of the well studied medicinal plant and its galls find excellent clinical and therapeutic applications. The present study reports the use of water extract from galls of R. chinensis as a reducing agent and formation of AgNPs from silver nitrate solution by a green synthesis route. The AgNPs formation was observed visually by color change and the absorbance peak at 450 nm was observed by UV-Visible spectrophotometer. The shape, size, and morphology of synthesized AgNPs were monitored by transmission electron microscopy and field-emission scanning electron microscopy. The face centered cubic structure of AgNPs was confirmed by X-ray diffraction pattern and element composition by energy dispersive X-ray analysis. The Fourier transform infrared spectroscopy spectrum revealed that the presence of components acts as a reducing and capping agent. The antibacterial activity was performed using the agar well diffusion method. Minimum inhibitory concentration and minimum bactericidal concentration were determined by broth dilution and spread plate method respectively. Synthesized nanoparticles were spotted as triangular and hexagonal shape and the particle size was around 150 nm. [ABSTRACT FROM AUTHOR]