Green synthesis of controlled size gold and silver nanoparticles using antioxidant as capping and reducing agent

Here silver (GA-AgNPs) and gold nanoparticles (GA-AuNPs) were synthesized by an ecofriendly method using antioxidant, gallic acid (GA) simultaneously as capping and reducing agent. Their size ranged between 15 nm and 80 nm, which was controlled or dependent on the feeding ratio of GA. There was a linear relationship between the particle sizes versus the GA content. Moreover, they indicated a negative zeta potential value, which was decreased from −33 mV to −40 mV for AgNPs and from −36 mV to −42 mV for AuNPs after the addition of GA. In a typical PEGylation reaction of them, resulted into a large increase in the particle size as well as zeta potential value. The cytotoxicity assay against human fibroblast cell line (WI-38) for 24 h and 3-days showed that they were completely safe toward these cells. Therefore, these engineered NPs could be considered promising supplementary targeting materials in future.