Fatemeh Lotfi Nejad - Department of Biology, Gorgan branch , Islamic azad university, Gorgan,Iran
Teena Dadgar - Medicinal plant research center, Gorgan branch , Islamic azad university, Gorgan,Iran
Mehdi Ebadi - Department of Chemistry, Gorgan Branch, Islamic Azad University, Gorgan ,Iran

Background and Aim : The resistance of the bacteria to the innumerous antimicrobial agents is a major challenge in the treatment of the infections demands to the necessity for searching and finding new sources of substances with antimicrobial properties. The present study, was done to evaluate the green synthesis of silver nanoparticles and in vitro investigation the antimicrobial activity of chitosan film solution enriched with EOs (CFs+Eos+ Ag NP)against microbial strains . Methods : biosynthesis of silver nanoparticles (AgNPs) by using peppermint essential oil was investigated The silver nanoparticles were characterized by means of UV-Visible spectroscopy, SEM and XRD analyzes. The antibacterial activity of chitosan films containing peppermint essential oil, silver nanoparticles, against gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa) and gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) was determined by well diffusion Assay.. In three replicates, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of different treatments including: ۱- essential oils (EOs), ۲- chitosan film solution (CFs), and ۳-chitosan film solution enriched with EOs (CFs+Eos+ Ag NP) were determined using microdilution technique against above mentioned microbes.Results : The silver nanoparticles were effectively synthesized by peppermint essential oils The results indicated that the chitosan films enriched with essential oils (CFs+Eos+AgPN) is capable of inhibiting the bacterial growth even at the lowest concentrations. these compounds had a better inhibitory effect on gram-positive isolates than gram-negative isolates.Conclusion : Chitosan-EOs complexes are the promising candidate for novel contact antimicrobial agents. Gram-positive bacteria were more sensitive to gram-negative bacteria than films prepared from chitosan containing different compounds. Considering the possibility of producing biodegradable films in nature that contain plant essential oils as anti-inflammatory compounds. The films have the potential to be used as active biodegradable films with strong antimicrobial effects

chitosan films, Antimicrobial Activity, silver nanoparticles