Sakineh Mashjoor - Department of Marine Biology, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran
Morteza Yousefzadi - Department of Marine Biology, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran

Background and Aims: The growing concern about bacterial strains resistant to antibiotics reveals the urgent need to discover and develop new types of bactericidal agents. Materials and Methods: In the present study, in a pioneering step to phycosynthesis of magnetic iron oxide nanoparticles (Fe۳O۴ MNPs) with antimicrobial potency, the process was initially exploited using an aqueous extract of green marine algae Ulva prolifera, and further evaluated the antimicrobial activity of biosynthetic magnetite nanoparticles against eight bacterial strains and three strains of fungi. Results: In the present study, the U. prolifera/Fe۳O۴-MNPs showed a strong inhibitory effect on gram-positive bacteria and relatively modest antifungal activity than fungal pathogenic agents. The highest antibacterial activity compared to strain Staphylococcus epidermidis (۱۹ ± ۰.۶ mm) and consequently in Bacillus subtilis (۱۸ ± ۰.۰۳ mm) and Bacillus pumulis (۱۸ ± ۰.۲ mm) were observed. However, the bactericidal effects of magnetite nanoparticles were more effective than gram-positive bacteria compared to gram-negative ones.  In the present study, we also observed a relatively modest antifungal activity in the anesthetized nanoparticles compared to Saccharomyces cervisiae (۱۱ ± ۰.۴ mm), and this was the most sensitive fungal strain relative to the fungicidal activity of these nanoparticles. Conclusions: The results of this study indicated that biosynthetic magnetite nanoparticles can be introduced as a new antibacterial to the pharmaceutical field and medicine.

Antimicrobial, Green seaweed, Magnetite nanoparticles, Biosynthesis, ضد میکروب, جلبک دریایی سبز, نانوذرات مگنتیت, زیست تولید