Synthesis and characterization of silver nanoparticles using Cynodon dactylon leaves and assessment of their antibacterial activity

Abstract

Many methods of synthesizing silver nanoparticles (Ag-NPs) by reducing Ag⁺ ions using aqueous/organic extracts of various plants have been reported in the past, but the methods are rather slow. In this investigation, silver nanoparticles were quickly synthesized from aqueous silver nitrate through a simple method using leaf extract of a plant--Cynodon dactylon which served as reducing agent, while sunlight acted as a catalyst. The formation of Ag-NPs was indicated by gradual change in colour and pH and confirmed by ultraviolet--visible spectroscopy. The Ag-NPs showed a surface plasmon resonance at 451 nm. Based on the decrease in pH, a possible mechanism of the synthesis of Ag-NPs involving hydroxyl (OH⁻) ions of polyphenols of the leaf extract is postulated. Ag-NPs having (111) and (200) crystal lattices were confirmed by X-ray diffraction. Scanning electron microscopy revealed the spherical nature of the Ag-NPs, while transmission electron microscopy showed that the nanoparticles were polydispersed with a size range of 8-10 nm. The synthesized Ag-NPs also demonstrated their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhimurium.

Green synthesis and characterization of silver nanoparticles by leaf extracts of Cycas circinalis, Ficus amplissima, Commelina benghalensis and Lippia nodiflora

“…3 ml of Plant extract was added to 60 ml of 10 -3 M AgNO 3 solution and the reaction was left to take place at ambient conditions [12]. The observed change in color from colorless to transparent yellow and finally to a dark brown with time indicates the formation of AgNPs.…”

Green Synthesis, Characterization and Antimicrobial Activity of Silver Nanoparticles Using Leaf Extracts of Carissa carandas

“…The observed absorbance peak at 420 nm (Fig. 1) is due to the surface plasmon resonance [16,21] and the appearance of peak shows the reduction of Ag + to silver nanoparticles hence it can be concluded that Carissa carandas leaf extract behaves as a reducing agent. The UV-visible analysis also showed that these nanoparticles were found to be stable even after six months.…”

“…Then the sample was kept into the incubator for 3 h in dark place, the colour changed from yellow to brown. It indicates synthesis of silver nanoparticles [20,21]. The solution after change of colour was used for further characterization of silver nanoparticles.…”

“…In this micrograph, silver nanoparticles can be observed as clusters and microstructure because of aggregation of particles and evaporation of solvent during sample preparation, due to this some variations in the particle size. However, in these silver nanoparticles, different shapes were observed ranging from spherical, rod shape to irregular in shape [20,21].…”

Synthesis and Characterization of Tio2 Nanoparticles Using Cynodon Dactylon Leaf Extract for Antibacterial and Anticancer (A549 Cell Lines) Activity

“…It also contains mineral constituents, crude proteins and chemical constituents like linolenic acid, hydro quinine, and hexadecanoic acid. It also shows the DNA protective activity [14,15]. In our research report, the small sized titanium dioxide nanoparticles was obtained, using of the Cynodon dactylon leaf extract and it is found to show a good antibacterial and anticancer activity against E. Coli and A549cell lines.…”