Samarium oxide coated by rutin: synthesis, antibiofilm, antivirulence and bactericidal activity evaluation

Biofilm formation, antibiotic resistance, and generation of virulence factors are key determinants in the pathogenicity of Pseudomonas aeruginosa. Nanotechnology presents innovative approaches for efficient drug delivery to combat bacterial infections. This study characterizes the effects of rutin-coated samarium oxide nanoparticles (Sm₂O₃-Rut NPs) on the planktonic and biofilm growth and virulence of P. aeruginosa. The Sm₂O₃-Rut NPs were characterized by FT-IR, DLS, zeta potential, EDX analyses, and ESEM microscopy. The effects of rutin, Sm₂O₃ NPs, and Sm₂O₃-Rut NPs on bacterial planktonic growth were investigated by broth microdilution assays. Bacterial biofilm formation, metabolic activity of biofilm, and bacterial survival within biofilm were quantified by crystal violet staining, TTC reduction, and CFU counting assays, respectively. The expression of the lasB and toxA genes was studied by qPCR. The fabricated Sm₂O₃-Rut NPs exhibited spherical shapes with an average size of 50.75 nm. The zeta potential and DLS size of the Sm₂O₃-Rut NPs were −1.5 mV and 214.8 nm and exhibited no impurities. The Sm₂O₃-Rut NPs showed the most intense inhibition of planktonic growth compared with bare rutin and Sm₂O₃ NPs, and significantly inhibited biofilm growth by 82.35%. In addition, Sm₂O₃-Rut NPs significantly reduced the metabolic activity and survival of bacterial cells embedded in a preformed biofilm by 90.78 and 20.58%, respectively. The expression of the toxA and lasB genes were significantly attenuated to 0.45 and 0.58 folds, after treatment of bacteria with Sm₂O₃-Rut NPs. This study underscores the potential of Sm₂O₃-Rut NPs in combating P. aeruginosa infections by targeting biofilm and virulence mechanisms.