Satellite particles were synthesized using a modified Turkevich approach, generating highly monodisperse colloids. In a pre-incubation step, chloroauric acid was reduced with sodium citrate in the presence of silver nitrate. Then, this solution is diluted in water and boiled until a red colloid is formed. The synthesis yields 20 nm AuNP capped with citrate. UV/Vis extinction spectroscopy and TEM were performed, and particles were used without purification.