Antimicrobial, antibiofilm potential, and anti-quorum sensing activity of silver nanoparticles synthesized from Cyanobacteria Oscillatoria princeps.

Cyanobacteria are among the beneficial and environmentally friendly natural candidates used in the biosynthesis of nanoparticles, with their ability to accumulate heavy metals from their environment, thanks to their biologically active compounds. In the current study, an aqueous extract of Oscillatoria princeps fresh biomass was used for the green synthesis of AgNPs. UV-vis spectrum, Fourier transforms infrared, scanning electron microscopy, and energy-dispersive spectroscopy were used to validate and characterize biosynthesized of OSC-AgNPs. The biosynthesis of AgNPs was visually verified in terms of the change in the color of the AgNO solution from yellowish brown to brown colors from 72 h onwards. An absorption peak of approximately 420 nm was detected in the UV-vis spectrum, corresponding to the plasmon resonance of AgNPs. FT-IR analysis showed the presence of free amino groups in addition to sulfur-containing amino acid derivatives that act as stabilizing agents. SEM images detected the roughly spherical shape of OSC-AgNPs with an average size of 38 nm. The pathogens tested were all susceptible to OSC-AgNPs showing varying antimicrobial effects on pathogenic microorganisms. E. coli and C. albicans displayed the maximum susceptibility, with zones of inhibition of 14.6 and 13.8 mm at 3-mM concentration, respectively, while B. cereus had the lowest zone of inhibition (10.6 mm) at 3-mM OSC-AgN0 concentration. In conclusion, AgNPs synthesized from Oscillatoria princeps inhibit biofilm formation, suggesting that AgNPs may be a promising candidate for the prevention and treatment of biofilm-associated infections caused by bacteria and yeasts.