Nanoparticles made from biodegradable polymers are of great interest for use in drug delivery systems due to their relative safety and ease of surface modification. My research focuses on the preparation of PLGA nanoparticles and investigation of endocytic and exocytic mechanisms included in their uptake across the nasal mucosa. Knowing these mechanisms will provide a much-needed understanding of nanoparticle trafficking which contributes to the design of effective delivery system to deliver drugs or vaccines intranasally.