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.