Characterization of Biosynthesis of Silver Nanoparticles and their Antibiofilm Activity against <i>Enterococcus faecalis</i>

Background: Due to the increasing presence of antibiotic resistance genes, treatment options for clinical infections are becoming increasingly limited. Objectives: This study aimed to synthesize, optimize, characterize, and evaluate the bioactivity of biogenic silver nanoparticles (Ag bioNPs) against a clinical isolate of E.faecalis. Materials and Methods: The formation of silver nanoparticles was confirmed under optimized conditions, with a UV-Vis absorption peak at 419 nm, and their crystal structures were verified by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis demonstrated the interaction of protein molecules with the nanoparticles, and transmission electron microscopy (TEM) revealed monodisperse spherical silver nanoparticles with sizes ranging from 2 to 7.5 nm. Results: The bacteria were capable of forming biofilms, with 37 samples exhibiting weak biofilm formation, 3 samples exhibiting moderate biofilm formation, and 10 samples exhibiting strong biofilm formation. However, adding 12.5 μg/ml of silver nanoparticles reduced bacterial growth and biofilm formation. Furthermore, increasing silver nanoparticles (AgNPs) dilution had an inhibitory effect on biofilm formation against E.faecalis samples. Conclusion: This study concluded that naturally made silver nanoparticles could be a cheap, environmentally friendly, and strong alternative to traditional methods for fighting infections, especially those caused by hard-to-treat germs like E.faecalis.