Facile green synthesis of selenium nanoparticles using olive (Olea europaea) leaf extract and their antimicrobial and antibiofilm properties

Abstract The spread of antibiotic-resistant microorganisms is increasing, posing a significant health threat to humans. The world is now using nanoparticles, particularly through green synthesis, as an effective alternative to traditional antimicrobials. Selenium nanoparticles (Se NPs) were produced from the Olea europaea plant extract and have been characterized using UV-Visible, FTIR, SEM, EDX, zeta potential, and HR-TEM. The antimicrobial effectiveness of Se NPs was evaluated against several microbial strains, including Staphylococcus aureus , Escherichia coli , Klebsiella pneumoniae , Citrobacter freundii , and Candida albicans , and its impact on their biofilm formation was tested. The UV-Vis spectrophotometer results displayed the highest absorption at 380 nm, indicating the synthesis of selenium nanoparticles. The biosynthesized Se NPs were uniform, well-dispersed, quasi-spherical in shape, and with particle sizes ranging from 2.60 to 4.75 nm. The antimicrobial activity analysis of Se NPs showed that C. albicans was mostly inhibited, recording an inhibition zone diameter of 35.98 ± 0.65 mm at 150 µg/mL. The antibiofilm assessment represented a 59.04% inhibition of C. albicans biofilm. In conclusion, Se NPs have proven to be economical, less toxic, and environmentally friendly antimicrobial agents for preventing and treating many bacterial and fungal infections.