Chitosan-based nanoparticles as a hepatitis B antigen delivery system.

The design of antigen delivery systems, particularly for mucosal surfaces, has been a focus of interest in recent years. In this chapter, we describe the preparation of chitosan-based particles as promising antigen delivery systems for mucosal surfaces already tested by our group with hepatitis B surface antigen. The final proof of the concept is always carried out with immunization studies performed in an appropriate animal model. However, before these important studies, it is advisable that the delivery system should be submitted to a variety of in vitro tests. Among several tests, the characterization of the particles (size, morphology, and zeta potential), the studies of antigen adsorption onto particles, the evaluation of toxicity of the particles, and the studies of particle uptake into lymphoid organs are the most important and will be described in this chapter.