Rational design of polymer-based nanosystems for an efficient targeting of the immune system

Abstract

The main goal of this thesis is the development of polymer-based nanosystems for antigen delivery to the immune system. To evaluate the influence of the physicochemical characteristics of the nanosystems in their biodistribution to the lymphatic system, we have developed two chitosan nanocapsule prototypes with different particle size and the corresponding nanoemulsions, apart from other nanocapsules with different polymeric coatings. Results have shown the importance of particle size, surface charge and specific characteristics of the polymers used as coating in the draining of the nanocarriers to the lymphatic system. Moreover, we have developed chitosan:carboxymethyl-β-glucan nanoparticles, with high ability to associate the model antigen ovalbumin and an adequate storage stability profile, both in suspension and in dry powder form. Finally, in vivo studies have shown a significant accumulation of the formulation in the lymph nodes, leading to an efficient antigen presentation to T cells. Overall, our results show the potential of polymer-based systems to be modulated in terms of their composition, aiming at a more effective immune response.