Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2016, Tutores: Maria Sarret Pons i Montserrat Mitjans ArnalNanotechnology has been advancing relentlessly and the use of nanoparticles has increased rapidly as they have been applied in numerous industrial and medical sectors. For instance, Silver nanoparticles can be found in aerosols, Zinc and Titanium oxides are important components of sunscreen and applications of different nanoparticles have proved to be relevant in biomedicine as multifunctional drug carriers or in novel cancer therapies. Nevertheless, potential dangers from nanoparticle exposure cannot be ignored. Nanoparticles may damage organisms. In vitro, studies have found certain nanoparticles to be able to break DNA helices, denaturalise vital proteins, disrupt gene expression or alter plasma coagulation. In vivo, they can induce inflammation and stimulate or suppress the immune system. Due to the ease of exposure to nanoparticles, the study and understanding of their potential toxicity is fundamental. The area of this research goes by the name of Nanotoxicology. Herein, different sized particles of ZnO, characterized by different methods, were used to study their interaction with plasma proteins, both human and rat. Plasma proteome alteration, as a result of the presence of ZnO in different conditions, has been evaluated in order to gain knowledge of potential toxicity from these nanoparticles and its consequences. Experimental results reported plasma coagulation delays, especially when studying the intrinsic coagulation pathway. Rat and human plasma were not equally affected by the ZnO particle’s presence; SDS-PAGE gels revealed significant differences among proteins adsorbed on the particles depending on the organism studied. The formation of a proteic coating on ZnO particles, the protein corona, was confirmed through observations on TEM and consequent stabilization of particle dispersion was reported by DLS