The attention for gold nanoparticles (AuNPs) has recently grown, especially regarding its applications in biomedicine, like cancer treatment and immunization by nano-vaccines. The interest for this type of nanoparticles is given by their ability to penetrate blood vessels and tissue barriers and to be targeted to a specific cell by means of specifically functionalized molecules. Moreover, AuNPs posses special properties which make them useful in concomitant diagnostic by medical imaging and tumor ablation by means of photothermal activation.