Deeper process understanding of chitosan nanoparticles as delivery system for immune actives

Mucosal vaccination via the respiratory tract is a promising therapeutic option. The uptake of the antigen in particulate form proves to be advantageous, so that nanoparticles represent a promising antigen carrier. This thesis focused on the production process and characterisation of chitosan nanoparticles in an application for mucosal vaccination.The aim of the work is to gain a detailed understanding of the manufacturing process of polymeric nanoparticles made of chitosan and carboxymethyl cellulose. The nanoparticles were prepared by ionic gelation. Chitosan, a positively charged polymer and carboxymethyl cellulose, negatively charged react with each other in an aqueous medium and cross-link to form nanoparticles. Ovalbumin, lysozyme, pepsin, avidin and lactalbumin were used as model antigens. The first part of this work displays the detailed characterisation of the interaction between chitosan and carboxymethyl cellulose utilising isothermal titration calorimetry and other methods to gain insight into the particle formation process. Influences on the stability of the nanoparticles, the size and the NP yield depending on the production method and the production pH were investigated. In the second part of this work, the complex dependencies of the various model antigens on the loading efficiency were analysed. Here, it was shown, that the loading efficiency was primarily dependent on the ratio of the two polymers. To prove effectiveness of the developed antigen carrier, the nanoparticles were loaded with K-Ras peptides, a specific tumour antigen that is found in certain forms of pancreatic cancer. In collaboration with the University Hospital Schleswig-Holstein, the specific activity of the K-Ras peptides against pancreatic ductal epithelial cells was demonstrated in in vitro cell studies. The comprehensive characterisation of the chitosan nanoparticles demonstrated that they represent a viable antigen platform for mucosal vaccination.