Synthesis of Silver Nanoparticles by Chemical Reduction Method and Their Antibacterial Activity

Silver nanoparticles were prepd. by chem. redn. method. Silver nitrate was taken as the metal precursor and hydrazine hydrate as a reducing agent. The formation of the silver nanoparticles was monitored using UV-Vis absorption spectroscopy. The UV-Vis spectroscopy revealed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption maxima at 418-420 nm from the UV-Vis spectrum. Comparison of theor. (Mie light scattering theory) and exptl. results showed that diam. of silver nanoparticles in colloidal soln. is about 60 nm. We have used energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and, UV-Vis spectroscopy to characterize the nanoparticles obtained. The energy-dispersive spectroscopy (EDX) of the nanoparticles dispersion confirmed the presence of elemental silver signal no peaks of other impurity were detected. The av. size and morphol. of silver nanoparticles were detd. by transmission electron microscopy (TEM). TEM photographs indicate that the nanopowders consist of well dispersed agglomerates of grains with a narrow size distribution (40 and 60 nm), whereas the radius of the individual particles are between 10 and 20 nm. The synthesized nanoparticles have been structurally characterized by X-ray diffraction and transmission high-energy electron diffraction (HEED). The peaks in the XRD pattern are in good agreement with the std. values of the face-centered-cubic form of metallic silver and no peaks of other impurity cryst. phases were detected. Addnl., the antibacterial activity of the nanoparticles dispersion was measured by Kirby-Bauer method. The nanoparticles of silver showed high antimicrobial and bactericidal activity against gram pos. bacteria such as Escherichia Coli, Pseudimonas aeruginosa and Staphylococcus aureus which is a highly methicillin resistant strain.