Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2018, Tutors: Carlos María Müller Jevenois, Gabriela Calderó LinnhoffToday, a big pharmaceutical research effort is dedicated to controlled and targeted release of drugs. One of the most innovative options is the use of nanoparticles as non-viral vectors for the controlled and/or targeted release of drugs towards target organs or tissues. In these fields, the use of polymer nanoparticles is widespread due to their versatility: they can be easily functionalized (polymers have reactive terminal groups such as carboxylic acids or amines) and therefore they are easily targeted to certain tissues or organs. Moreover, given the high (and modulable) biodegradability of certain polymers such as poly(lactic acid) (PLA) or poly(lactic-coglycolic) acid (PLGA) the rate of drug release can be easily controlled. This work focuses on the preparation and characterization of polymer nanoparticles made of ethylcellulose and PLGA from template nano-emulsions. By the incorporation of a cationic surfactant in the formulation, positive surface charges were attained. Positively charged nanoparticles allow for strong electrostatic interactions with anionic molecules such as proteins, which could be interesting for the design of targeted and controlled drug release systems. Nano-emulsions were prepared by the PIC method using two slightly different techniques and were characterized by DLS (dynamic light scattering) and light transmittance versus time experiments. Nanoparticles were prepared by solvent evaporation and were characterized by DLS and Zpotential measurements. Their interaction with seroalbumin, the major protein in blood, was also studied through DLS and Z-potential measurements.