In the present proposal we want to address three specific aims. First of all we want to obtain a clear picture about the ability of antimicrobial agents to diffuse into biofilms. Secondly, we want te develop novel inhibitors of the QS system and evaluate their ability to interfere with microbial biofilm formation. Finally, we want to develop novel carriers for antimicrobial agents (including QSI) in order to increase their efficient delivery into biofilms.