Maryam Alsadat Mehrbakhsh Bandari - Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran
Leila Asadpour - Department of Biology, Rasht Branch, Islamic Azad University, Rasht, Iran
Afshin Pourahmad - Department of Chemistry, Rasht Branch, Islamic Azad University, Rasht, Iran

Background and Aims: Drug resistance, particularly methicillin resistant in Staphylococcus aureus strain is a major worldwide public health concern. The present study aimed to synthetize selenium nanoparticles, investigate its antibacterial effect and its ability to be used as ampicillin nanocarrier. Materials and Methods: Selenium nanoparticles were synthetized via chemical regeneration of sodium selenite by L-systein amino acid. Loading of ampicillin on the surface of selenium nanoparticles was done by gradual addition of antibiotic to nanoparticle solution and continuous shaking. Then this attachment was investigated by using UV-Vis spectroscopy, XRD and scanning electron microscope. Antibacterial properties of produced selenium nanoparticles and antibiotic loaded selenium nanoparticles against standard strain of S. aureus and ۱۰ methicillin resistant S. aureus strains were tested by disc diffusion method. Minimum inhibitory concentration (MIC) of bacterial growth was determined by broth macrodilution method. Results: The produced selenium nanoparticles showed antibacterial effect against all strains of S. aureus. Loading of ampicillin on the surface of selenium nanoparticles enhanced the antimicrobial activity of this drug. The mean MIC of selenium nanoparticles against S. aureus strains ranged between ۷.۸-۶۲.۵ µg/mL free form of ampicillin between ۶۲.۵- ۲۵۰ and ampicillin bound to nanoparticles was ۷.۸-۷.۸ μg / mL. These values for standard strain of Staphylococcus aureus strains were ۷.۸, ۳۱.۲ and ۳.۹ μg / mL, respectively. Loading of ampicillin on the surface of selenium nanoparticles enhanced the MIC against methicillin resistant S. aureus. Conclusions: The obtained results confirmed antibacterial activity of selenium nanoparticles. Enhancing the antibacterial activity of antibiotics loaded on the surface of nanoparticles, increases the possibility of application of these drugs especially for the elimination of hard-to-heal infective diseases.

Selenium Nanoparticles (Se NPs), Antibacterial Activity, Methicillin Resistant S. aureus, Ampicillin, نانوذرات سلنیم, اثر ضد میکروبی, استافیلوکوکوس اورئوس مقاوم به متی سیلین, آمپی سیلین