Peyers patches have a potential role not only in the mucosal but also in the systemic immune responses against pathogens. Recently, Peyers patches and their immune cells are important to be targeted with proteins or antigens for nanobiology and nanomedicine applications. Nanoparticles have several advantages as good models for vaccine delivery. Nanoparticles uptake by Peyers patches introduces the possibility of accommodate vaccines for oral immunization. Particle size is one of the most important factors in the uptake and pathway of nanoparticles into the gastrointestinal tract especially...