Surface modification of citrate-reduced colloidal gold nanoparticles with 2-mercaptosuccinic acid

Surface modification of citrate-reduced gold nanoparticles with 2-mercaptosuccinic acid (MSA) was carried out in the aqueous phase. This provides a way to obtain carboxylic acid functionalized gold nanoparticles with diameter above 10 nm. The influence of the protecting MSA layer on the behavior of the modified gold nanoparticles in comparison with that of the traditional citrate-reduced gold colloid was evaluated by HCl titration, cyanide etching, and seeded growth tests. The modified gold nanoparticles show an improved stability against pH changes and cyanide etching. They do show further growth, which appears to be more homogeneous than for the unmodified particles