Preparation and evaluation of sodium alginate nanoparticles containing CRM197 protein by ionic gelation method

Development of the recombinant vaccines against infectious diseases is dependent on the identification of immunogenic antigens and vaccine delivery systems such as polymeric nanoparticles that are able to stimulate immune responses similar to or better than conventional vaccines and reduce complications associated with traditional vaccines. At the present study, synthesis and properties of the sodium alginate nanoparticles carrying CRM197 protein as an antigen delivery system were evaluated. Synthesis of the blank optimized without protein loading and protein-containing nanoparticles was performed by ionic gelation method. After designing of the experiment (DoE) and determining the influential physicochemical factors in ideal nanoparticles synthesis; size, zeta potential, morphology, encapsulation efficiency, release pattern and FT-IR spectroscopy were investigated. The optimized nanoparticles were prepared at a concentration of 0.2% w/v sodium alginate, 0.1% w/v calcium chloride, 0.04% w/v poly-L-lysine during 45 minutes of stirring at 2000 rpm and in pH 6.5. The average nanoparticle size for blank and CRM197 loaded nanoparticles were 88 and 245 nm also zeta potential -21 and -24.2 mV, respectively. LE and LC were >80% and >20%, respectively, associated with a stable and long-term encapsulated protein release pattern from nanoparticles. Absence of local and systemic signs, as well as weight gain in the mice group studied, indicated the safety of the nanoparticles and CRM197 protein combination. Based upon the above achievements, alginate nanoparticles can be used as an antigen delivery system for targeted delivery with controlled, slow release and improved stability of recombinant diphtheria antigen (CRM197) for immunization against diphtheria disease.