The gold particles are made in just a few minutes by simply adding sodium hydroxide to the reaction mixture. The chemical acts as an initiator for the reduction of HAuCl4 in aqueous solution in the presence of polyvinylpyrrolidone without the use of any reducing agent. To control the size of the AuNPs, the researchers simply adjust the PVP/HAuCl4 ratio.

The PVP-stabilized AuNPs demonstrate remarkable in vitro stability in a wide range of ionic strength (0–30 M), temperature (4–100 °C), pH (4.4–13.5), various buffer solutions and physiological conditions.

The generation of PVP-stabilized AuNPs has been found to be non-toxic as assessed through MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. Also, the production strategy features several green concepts: the choice of friendly solvent, the selection of friendly benign and non-toxic reducing and capping agents, the one-step reaction at room temperature and a reaction time of just a few minutes.

The researchers presented their work in the journal Nanotechnology.