“Green” seed-mediated synthesis and morphology of Au nanoparticles using β-cyclodextrin

Abstract

Gold nanoparticles (NPs) with dendritic morphology were synthesized by a “green” seed-mediated approach in the presence of β-cyclodextrin (β-CD) as stabilizing biocompatible capping agent. First, 50 mL of an aqueous solution containing 5 mM of β-CD were prepared, to which a variable amount of HAuCl4 was added. The β-CD/Au molar ratio was monitored from 20 to 200. Optical properties, including Surface-Enhanced Raman Scattering (SERS) activity, of the synthesized structures were characterized by Raman and UV-vis spectroscopies. Morphology was studied by transmission electron microscopy (TEM). Samples prepared using this procedure presents an increase of their SERS signal with respect to samples without peak-rich morphology. Optimized nanodendrites were obtained at a β-CD/Au molar ratio of 100. Moreover, a growth mechanism is proposed to describe the β-cyclodextrin role in the synthesis of Au nanodendrites. The “green” seed-mediated synthesis technique used herein produces Au NPs with good biocompatibility pointing them out for biomedical applications.