Biosynthesis of gold nanoparticles using a kind of flavonol: Dihydromyricetin

The present paper investigated the biosynthesis of gold nanoparticles (AuNPs) using dihydromyricetin (DMY) without adding external surfactant, capping agent or template. The synthesized nanoparticles were characterized by using UV–vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and particle size analyzer. TEM images showed that anisotropic growth of AuNPs happened at pH = 4.5 and 5.5 and relatively uniform small spherical shaped gold nanoparticles were obtained at pH = 6.5 and 8.5. Furthermore, both the ratios of nHAuCl4/nDMY and process temperatures were discussed, respectively. DMY or DMY oxidation products which made AuNPs solution stable were directly adsorbed on the surface of AuNPs at the ratio of nHAuCl4/nDMY being 1:3 and 1:1 in the reduction process. Besides, the monodisperse and uniform AuNPs were easily obtained at higher temperatures (90 °C). Based on the FTIR analysis, hydroxyl groups of DMY played an important reduction role during synthesis process. The experimental approach is simple, rapid, cost-effective and reproducible at room temperature.