2. Some gold nanoparticle synthesis processes

It would be too ambitious to give an exhaustive list of methods for synthesizing gold nanoparticles, but they can be grouped into a few broad categories:

• chemical synthesis in aqueous or organic solution ;

• chemical synthesis on surfaces ;

• ultra-high-vacuum preparations of gold NPs deposited on a surface.

Other more original methods include mass sorting of gold aggregates, sonolysis, or even intra-cellular reduction by green algae.