Project Description. This thesis is focused on the study of the properties of gold nanoparticle (NPsAu) systems coated lanthanide ions (Ln+3 = La, Ce, Gd y Eu). This coating was carried out by functionalizing the NPsAu with amino acid based on the chemical properties of the amino groups (-NH2) and of the carboxyl groups (-COOH) present in these biomolecules, that act as links between the nanoparticles and lanthanide ions to promote the formation of hybrids NPsAu-Ln. In this study obtained hybrids NpsAu Ln by varying the reaction pH and to this was initially assessed with the gadolinium ion in order to find the means which produces the best adsorption for then apply to the other lanthanides. It is interesting to study of these materials, combining the plasmon resonance of the NPsAu with the unusual properties of lanthanides ions (Magnetic and luminescent properties). This combination makes these materials potential candidates for application as biosensors, diagnostic tool and disease detection, formers bioimages, etc.