Optimization of conditions for conjugation of outer membrane vesicles of Salmonella Typhimurium with oral delivery systems using response surface method

ABSTRACT Background Outer membrane vesicles (OMVs) released from Salmonella Typhimurium can become the effective vaccine candidate. For efficient delivery through oral route, the OMVs are conjugated with some delivery systems. The current study was aimed at optimization of conditions required for conjugation of OMVs with nano- or microparticles for maximum entrapment of OMV in terms of protein concentration. Methods The OMVs of Salmonella Typhimurium were conjugated under three optimum conditions of pH, temperature and ratio (nanoparticles or microparticles: OMVs) predicted by response surface method. The efficiency of conjugation was determined by entrapment of OMVs in nano/microparticles. Result The pH and temperature were not influential conditions in case of conjugation of OMVs with chitosan nanoparticles (Ch-NP) and poly-lactide co-glycolide microparticles (PLG-MP) while they had influence in case of poly(anhydride) nanoparticles. In case of Ch-NP and PLG-MP, the optimum ratio for maximum entrapment was found to be 1:10 and 1:9 respectively. The optimum pH and temperature was found to be 7 and 24°C respectively for conjugation of poly(anhydride) nanoparticles. The optimized conditions did not alter the protein profile and immunogenic potential of conjugated vaccines.