THE IMMUNOGENIC EFFECTS OF CHITOSAN COATINGS ON PLGA NANOPARTICLES FOR VACCINE FORMULATIONS
One approach of novel mucosal vaccines is the use of chitosan, which has shown potential as a versatile and effective coating material on nanoparticles (NPs) for improving efficacy. Various mechanisms are recognised to lead to improved immune response, however it is unclear how variations of chitosan molecules with differing properties affects the immunogenicity on dendritic cells (DCs). This study investigated the effects of different chitosan on the coating properties on PLGA NPs and subsequent immunogenicity.
Chitosans with varying molecular properties were coated onto PLGA NPs. The resulting NPs were characterised for size and zeta potential, quantification of chitosan adsorption on the NP surface, and immunogenicity through expression of CD40, CD86.
PLGA NPs with different chitosan coatings exhibited differing particle characteristics, degrees of adsorption, and subsequent surface adsorption of model antigen protein. The relationship between the amount of chitosan adsorbed onto the particle surface and the resulting NP size increase differed for each chitosan. As expected, the surface charge also varied greatly, and the chitosans exhibited a concentration dependent immunogenicity.
Coating PLGA NPs with differing forms of chitosan, including salt form, degree of quaternisation, molecular weight, oligomerisation, carboxymethylation, all contribute to NPs containing unique characteristics and immunogenicity.