Antimicrobial properties of nanocomposite films containing silver nanoparticles

Abstract

Metal particles are added to polymers used in the food packaging to improve their mechanical and antimicrobial properties. In this study, the antimicrobial properties of low-density polyethylene nanocomposite (LDPE) containing 17.5%, 12.5%, 7.5%, and 2.5% silver nanoparticles were investigated. UV-Visible, SEM, and XRD tests were used to confirmation of the synthesis of silver nanoparticles, characterization of silver particle distribution, and silver crystal structure. Crystal nanoparticles with an average size of 20 nanometers were approved. To evaluate the antimicrobial properties of silver nanocomposites, bacterial growth in the presence of nanosilver films with the mentioned percentages was measured by optical density (OD) method via spectrophotometer (600 nm). Besides, the migration of nanoparticles was measured. The results showed that the coating containing 17.5% and 2.5% nanosilver had the highest and the lowest effect, respectively and in comparison to the other groups. Also, comparing the effect of coatings on two types of food pathogens, E. coli and S. aureus, showed that the effect of coatings on S. aureus was higher. The results showed a correlation between the percentage of silver nanoparticles used and antimicrobial properties. Furthermore, with increasing the percentage of silver nanoparticles, the releasing rate of nanoparticles from the coating increased. Finally, due to the migration of silver nanoparticles from all four types of nanocomposite coatings in the permitted range, 17.5% coating was selected as the most efficient one.

Keywords

• silver nanocomposite
• antibacterial
• migration