Preparation and characterization of gold nanoparticles with amino acids, examination of their stability

We report a novel strategy for the synthesis and capping of gold nanoparticles (GNPs) by tryptophan, glutamic acid and aspartic acid. The ratio of chloroaurate ions to amino acid was optimized in the reaction medium to obtain monodispersed GNPs. The size of nanoparticles and size distribution were controlled by sodium dodecyl sulfate which demonstrated high stability in aqueous solution over a period of time. GNPs were characterized by UV-Vis spectroscopy, dynamic light scattering and transmission electron microscopy.