Development and characterization of alginate coated low molecular weight chitosan nanoparticles as new carriers for oral vaccine delivery in mice

• Nanoparticles were prepared by using different low MW of CS (42, 74 and 106 kDa).
• Alginate coating onto CS LMW nanoparticles protect antigen in acidic condition.
• Degree of toxicity was not affected significantly due to difference of MW of CS.
• Significant correlation was observed between the immune response with CS MW.

In the present study, nanoparticles of low MW chitosan (CS) were formulated in which measles antigen was entrapped and subsequently coated with sodium alginate. The size and surface properties of the nanoparticle can be tuned with different MW of CS. In vitro release studies showed initial burst release followed by extended release, best fitted in the Makoid–Banakar model (R2 > 0.98). SDS-PAGE assay revealed that alginate coating could effectively protect antigen in acidic condition for at least 2 h. Cell viability was assessed using MTT assay into HT 29 cell line. Formulations were orally administered to mice and immunological responses were evaluated using ELISA method. Obtained results showed that measles antigen-loaded CS nanoparticles induced strong immune response and significant correlation was observed between the immune response with CS MW. Protecting ability of antigen in gastric environment, sustained release kinetics, systemic and mucosal immune responses and low cytotoxicity observed for the alginate coated nanoparticles demonstrated that LMW CS could be promising platform for oral vaccine delivery.