Green synthesis of phytochemical-stabilized Au nanoparticles under ambient conditions and their biocompatibility and antioxidative activity

Green chemical synthesis of Au nanoparticles (NPs) has been of great interest because of its potential biomedical applications. In this study, we successfully produced phytochemical-induced Au NPs cofunctionalized with gallic acid, protocatechuic acid, and isoflavone. They have a strong antioxidant effect and serve as effective reducing agents, inducing the immediate passivation of Au NPs. The properties of these green chemical Au NPs were characterized by TEM, UV/Vis and FT-IR spectroscopy, and xi-potential measurements, and the Au NPs exhibited excellent homogeneity with an average diameter of 20 nm and high dispersity at all pH ranges, with long-term stability as well as excellent cytocompatibility. Molecular dynamics (MD) simulations were also carried out in order to reveal the surface stability of the Au NPs. The computational results indicate that there are strong interactions between the phytochemicals and Au NPs, especially in the Au/protocatechuic acid-isoflavone model. Phytochemical-stabilized Au NPs allowed about 40% H2O2 to be removed at an NP concentration of 50 mu g mL(-1); this removal rate is the same as that achieved by 3000 units per mg catalase. Therefore, this novel synthesis route for Au NPs using phytochemical reducing agents may be effectively exploited for nonthermal-assisted reactions and one-pot processes of biological applications.