Synthesis of Eco-Friendly Silver Nanoparticles Using Glycyrrhizin and Evaluation of Their Antibacterial Ability
Danni Feng, Renyin Zhang, Mengting Zhang, Ashe Fang, Feng Shi
Abstract
In the present study, the biosynthesis of silver nanoparticles (AgNPs) and their antibacterial activity against gram-positive and gram-negative bacteria were investigated. Glycyrrhizin (GL) was used as a reducing agent and stabilizer to rapidly prepare the AgNPs. The distinctive absorption peak at 419 nm confirmed the formation of GL-reduced AgNPs. The TEM and particle size analysis shows that the prepared GL-reduced AgNPs were mostly circular with good dispersion and a relatively uniform particle size of 35 nm on average. Fourier transform infrared spectroscopy analysis was performed to identify the possible biomolecules in the capping and active stabilization of the GL-reduced AgNPs. The antibacterial activity of the GL-reduced AgNPs was analyzed with the Oxford cup diffusion method and filter paper diffusion method. The experimental results show that these properties endowed the GL-reduced AgNPs with high antibacterial activity against Escherichia coli and Staphylococcus aureus and lay a foundation for the use of colloidal silver in antibacterial applications. The GL-reduced AgNPs also had stronger antibacterial activity than sodium citrate-reduced AgNPs, which indicates the advantages of GL-reduced AgNPs compared with sodium citrate-reduced AgNPs in inducing bacteriostasis. The cytotoxicity of GL-reduced AgNPs on human kidney epithelial 293A (HEK293) cells was evaluated via the MTT assay. The results show that GL-reduced AgNPs had lower toxicity to HEK293 cells than sodium citrate-AgNPs, which indicates that the as-prepared GL-reduced AgNPs are environmentally friendly.