Green synthesis of gallic acid-coated silver nanoparticles with high antimicrobial activity and low cytotoxicity to normal cells

Antibiotic resistance creates a challenge for developing new drugs to overcome infections. Silver nanoparticles (AgNPs) have become an attractive alternative to antibiotics due to their broad-spectrum antimicrobial activity. In this study, we synthesized silver nanoparticles coated with gallic acid (GA) using a simple and green method in which GA acted as the reducing and stabilizing agent. The morphology, size and absorption peak of GA-AgNPs were determined by transmission electron microscopy (TEM), dynamic light scattering (DLS) and UV-vis spectroscopy, respectively. The GA-AgNPs demonstrated antimicrobial activity against two bacterial strains, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and one fungus, Candida albicans (C. albicans), with minimum inhibitory concentrations of 6, 30 and 24 μg/mL, respectively. The cytotoxicity study demonstrated that GA-AgNPs had fewer toxic effects on normal cells than on cancerous cells. This study indicated GA-AgNPs could be a new potential candidate for use in biological and pharmaceutical applications for fighting infections caused by microorganisms.