Development of nanoparticle-in-microsphere(Nimos) system for oral delivery of vaccine and antibody against ped virus for swine

Abstract

PED virus is a major barrier to the animal farming industry, and it is the main cause of the mortality of suckling piglets up to 95% by enteric infection. The 2C10 monoclonal antibody (mAb) obtained from Nicotiana benthamiana produced by transient expression was indicated as one of the potential candidates is an antibody against PEDV by oral delivery. The biologics are a new wave of pharmaceuticals and have been continuously developing, which has various benefits of low toxicity and high specificity. However, it unsuitable for use with oral drug delivery owing to limitations of the strong acidity and protease of the GI tract. Therefore, to overcome these limitations, the development of oral drug delivery is essential for biologics to enhance stability. The pH-responsive microbeads were used as a carrier for oral delivery and the alginate-chitosan is a well-known material, some properties protect biologics from an inappropriate environment of the GI tract. The concentration of alginate-chitosan was optimized for pH-responsive beads construction, which the 2% alginate and 1% chitosan is a suitable qualification. Then the physical characterization of pH-responsive microbeads includes the diameter size measurement by digital vernier, found that the distribution of diameter size was between 1.5-1.6 mm which was more than 70%. The SEM showed that the surface of pH-responsive microbeads was a network structure with varying porosity, meanwhile, the TEM demonstrates to the nanoparticles kept in microbeads. Further, the release behaviour for pH-responsive microbeads in simulated physiological fluids (SPF) was investigated under a fluorescent microscope, it was found that the pH-responsive microbeads could protect and retain the nanoparticles from SPF. In the last step, the biologics encapsulated with microbeads were tested with SPF, after that, it evaluated the efficacy by Real-Time PCR. From the result, both the viral-like particles and the 2C10 mAb still stable, even though, was tested with SPF. In summary, the alginate-chitosan is efficient enough to retain the nanoparticles, and the pH-responsive microbeads can use as a carrier for oral drug delivery owing to could be protected from an acidic environment and released the nanoparticles to the target area.