Synthesis and antibacterial activity of silver/reduced graphene oxide nanocomposites against Salmonella typhimurium and Staphylococcus aureus

Abstract

In this study, silver/reduced graphene oxide (Ag/rGO) nanocomposites were synthesized in situ using three different mass ratios of silver nitrate and graphene oxide (1:1, 2:1, and 4:1). L-ascorbic acid (LAA) was used as an environment-friendly reducing agent. The characterization of Ag/rGO was investigated using Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The investigated results showed that the Ag/rGO nanocomposites were successfully synthesized with silver nanoparticles in the size range of 10-25 nm uniform distribution on rGO sheets. The antibacterial activity of Ag/rGO was tested against Gram-negative (Salmonella typhimurium) and Grampositive (Staphylococcus aureus) bacteria using plate colony-counting and broth dilution methods, in comparison with individual rGO and silver nanoparticles. The tested results showed that the Ag/rGO nanocomposite with the AgNO3:GO ratio of 4:1 (Ag/rGO4:1) exhibited the strongest antibacterial activity. The minimal inhibitory concentration values of Ag/rGO4:1 against Salmonella typhimurium and Staphylococcus aureus were 10 µg/ml and 50 µg/ml, respectively. Hence, the Ag/rGO nanocomposite could be considered as a potential antibacterial agent.

Keywords

• nanocomposite
• Salmonella typhimurium
• silver/reduced graphene oxide
• Staphylococcus aureus