Physicochemical and biological characterization and applications of silver nanoparticles obtained by green synthesis using Cichorium intybus

Abstract

Recent advances in nanotechnology have made it possible to obtain different types of nanomaterials, including silver nanoparticles (AgNPs). In this work, AgNPs obtained by green synthesis using an extract of leaves of Cichorium intybus were characterized, and their antibacterial mechanism was studied. RAMAN analysis indicated that chicoric acid is not only the main reducing agent for silver (I) cations but also stabilizes the AgNPs. Afterwards, the antimicrobial characterization of these AgNPs against Escherichia coli and Staphylococcus aureus was conducted. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values obtained support the antibacterial effect. Growth curves and death rate data of these AgNPs, showing a killing kinetics faster for E. coli than for S. aureus. Regarding the mechanism of action, AgNPs were capable of damaging the bacterial membranes of both studied bacteria. In the case of E. coli, it was also proven that AgNPs increase the intracellular reactive oxygen species. Finally, when the effects on the bacterial biofilm were evaluated, the AgNPs showed the ability to eradicate preformed biofilms of E. coli and S. aureus. The results obtained allowed us to expand the knowledge of green AgNPs in their characterization and in their antibacterial activity, which opens up their possible use as new therapeutic strategies.