Development of chitosan-pullulan composite nanoparticles for nasal delivery of vaccines: optimisation and cellular studies

Nasal immunisation with nanoparticles has already shown promising results. In this study, nanoparticle composites carrying BSA for nasal vaccination prepared using electrostatic interaction process between polycation N-trimethyl chitosan chloride (TMC), chitosan glutamate (CG), chitosan chloride (CCl) and polyanion carboxymethyl pullulan (CMP). A mass ratio of 2:1 for TMC-CMP combination produced stable nanocarriers. For CCl-CMP and CG-CMP formulations needed a mass ratio of 3:1. Loading efficiency was >90% for all formulations. Nanoparticles' size ranged from 207 to 603 nm. The surface charge of the complexes varied between +14 and +33 mV. SDS-PAGE integrity of the model antigen was also demonstrated. MTT studies showed that nanoparticle composites were less toxic to Calu-3 cells than the particles of cationic polymers alone. FITC-BSA loaded nanoparticles efficiently taken up by J774A.1 macrophages as confirmed by confocal microscopy highlighting the potential of these novel nanoparticulate carriers' use for nasal vaccination.