Synthesis of Ag and Ag-SiO2 nanoparticles by γ-irradiation and their antibacterial and antifungal efficiency against Salmonella enterica serovar Typhimurium and Botrytis cinerea

The Ag and Ag-SiO2 nanoparticles were synthesized by gamma-irradiation, and characterized by field-emission transmittance electron microscopy (FE-TEM), field-emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDXS). The electron microscopy images show that well-dispersed Ag nanoparticles of about 7 nm were attached to the surface of SiO2 nanoparticles of about 350 nm. Antibacterial efficiency of the Ag-SiO2 nanoparticles was tested against Salmonella enterica serovar Typhimurium by measuring the optical density (OD). Without Ag-SiO2 Particles, the S. enterica serovar Typhimurium grow gradually, and reach a steady state (fully grow) in about 6 h. At the presence of Ag-SiO2 particles at 50 ppm, their growth became much slower, reaching a steady state after about 24 h. With Ag-SiO2 particles at 100 ppm, they did not grow fully even after 58 h. The antifungal efficiency of the Ag-SiO2 nanoparticles against Botrytis cinerea was about 65.0, 99.9, and 99.9% at the concentrations of the particles of 10, 50, and 100 ppm, respectively. (c) 2005 Elsevier B.V. All rights reserved.