Size-controlled synthesis of monodispersed gold nanoparticles stabilized by polyelectrolyte-functionalized ionic liquid.

The size-controlled synthesis of monodispersed gold nanoparticles (AuNPs) stabilized by polyelectrolyte-functionalized ionic liquid (PFIL) is described. The resulting AuNPs' size, with a narrow distribution, can be tuned by the concentration of HAuCl(4). Such PFIL-stabilized AuNPs (PFIL-AuNPs) showed a high stability in water at room temperature for at least one month; they were also quite stable in solutions of pH 7-13 and high concentration of NaCl. In addition, the PFIL-AuNPs exhibited obvious electrocatalytical activity toward β-nicotinamide adenine dinucleotide (NADH for short, a cofactor in enzymatic reactions of NAD(+)/NADH(-)-dependent dehydrogenases) oxidation, suggesting a potential application for bioelectroanalysis.