In Vivo Sustained Release of Peptide Vaccine Mediated by Dendritic Mesoporous Silica Nanocarriers

Mesoporous silica nanoparticles have drawn increasing attention as promising candidates in vaccine delivery. Previous studies evaluating silica-based vaccine delivery systems concentrated largely on macromolecular antigens, such as inactivated whole viruses. In this study, we synthesized dendritic mesoporous silica nanoparticles (DMSNs), and we evaluated their effectiveness as delivery platforms for peptide-based subunit vaccines. We encapsulated and tested in vivo an earlier reported foot-and-mouth disease virus (FMDV) peptide vaccine (B₂T). The B₂T@DMSNs formulation contained the peptide vaccine and the DMSNs without further need of other compounds neither adjuvants nor emulsions. We measured in vitro a sustained release up to 930 h. B₂T@DMSNs-57 and B₂T@DMSNs-156 released 23.7% (135 µg) and 22.8% (132 µg) of the total B₂T. The formation of a corona of serum proteins around the DMSNs increased the B₂T release up to 61% (348 µg/mg) and 80% (464 µg/mg) for B₂T@DMSNs-57 and B₂T@DMSNs-156. In vitro results point out to a longer sustained release, assisted by the formation of a protein corona around DMSNs, compared to the reference formulation (i.e., B₂T emulsified in Montanide). We further confirmed in vivo immunogenicity of B₂T@DMSNs in a particle size-dependent manner. Since B₂T@DMSNs elicited specific immune responses in mice with high IgG production like the reference B₂T@Montanide™, self-adjuvant properties of the DMSNs could be ascribed. Our results display DMSNs as efficacious nanocarriers for peptide-based vaccine administration.