Green Synthesis of Silver Nanoparticles Using Hypericum perforatum L. Extract and Evaluation of Their Antibacterial Activity
Silver nanoparticles (AgNPs) ranging in size from 1-100 nm show good application potential in many medical fields (therapies, medical devices, molecular diagnostics) due to their antimicrobial properties. The purpose of this study is to characterize from physicochemical perspective the colloidal dispersion obtained through phyto-synthesis. The existence of colloidal silver particles was visually highlighted through Thyndall effect. The bio-reduction of silver ions was analyzed through modern techniques, UV-VIS spectrophotometry and Hyperspectral Microscopy. After getting the colloidal dispersion, its antibacterial activity was proved by sowing on different plates the following types of pathogenic agents: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa. The UV-VIS spectrum for the methanolic extract with 10% H. perforatum L. and for the silver colloidal dispersions was achieved, observing a max at 455 nm. The hyperspectral images were achieved observing the shape, conformation, and the size of the obtained particles. During the antibacterial efficacy testing on those three strains of pathological agents, in all situations, the colloidal dispersion had a promising antimicrobial effect.