Evaluation of antimicrobial property of silver nanoparticle biosynthesized by Rosemary Plant

Abstract

Background and Aim:Inthe recent decades, increased development of biosynthesis of nanoparticles is inevitable because of its incredible applications in all fields of science. The field of nanotechnology is one of the most practical areas of research in modern materials science. Nanoparticles exhibit completely new or improved properties based on specific characteristics such as size, distribution and morphology. The most important and distinct property of nanoparticles is that they have the larger ratio of surface area to volume. Biosynthesis of nanoparticles by plant extracts is currently developing. One of the most important applications of nanoparticles is the property of their antibiotic against bacteria.The purpose of this study was to investigate the antimicrobial properties of silver nanoparticles produced by biological methods. Methods:In this study, Rosemary extract were used as a reducing agent for the biological production of silver nanoparticles (AgNPs). Adding Rosemary extract to silver nitrate at the temperature of the room will also change the color of the solution. This color change is indicative of nanoparticles production. To ensure that silver nanoparticles produced, the particle size was evaluated by Particle Size Analyzer. Finally, the antimicrobial activity of silver nanoparticles was investigated. Mueller Hinton (MH) agar medium was used to cultivate bacteria. Fresh overnight cultures were taken and then we covered the MH agar plates by 100 Gl of inoculum. The antibacterial activity of silver nanoparticles was studied against Staphylococcus aureus (ATCC6538P) and Escherichia coli (ATCC 8739) by the agar disc diffusion method. Results:It is obvious that silver nanoparticles indicated yellowish brown color in aqueous solution due to excitation of surface plasmon vibrations in silver nanoparticles. While mixed with aqueous solution of the silver nitrate, Rosemary extract started to change the color from watery to brown due to reduction of silver ion, indicated the formation of silver nanoparticles. There was a gradual increase in color development in the reaction mixture (silver nitrate solution + plant extract). The results showed that the silver nanoparticles which made by Rosemary have good antimicrobial properties for Gram-positive and gram-negative bacteria. Conclusion:Developing a reliable and eco-friendly process for synthesis of metallic nanoparticles is an important requirement in the field of nanotechnology. We have demonstrated that use of Rosemary extracts as a natural, low cost biological reducing agent can produce metal nanostructures using efficient green nanochemistry methodology, avoiding the presence of toxic solvents and waste. The biosynthesized silver nanoparticles using Rosemary extract proved excellent antimicrobial activity. The antimicrobial activity is well demonstrated by considerable zone of inhibition against Escherichia coli and Staphylococcus aureus. This study showed a simple, rapid and economical method to synthesize silver nanoparticles.