Needle-free immunization using a solid-in-oil nanodispersion enhanced by a skin-permeable oligoarginine peptide.

The objective of transcutaneous immunization is efficient vaccination using the skin's immune system. Although a less invasive administration procedure is involved, the effective delivery of antigen using this modality remains a problem. Here, we demonstrate the use of a solid-in-oil (S/O) nanodispersion system for the transcutaneous immunization of male ddY mice with ovalbumin (OVA) antigen. The S/O nanoparticles consisted of OVA and hydrophobic surfactant molecules and were dispersed in oil; enhanced induction of antigen-specific antibody was observed after the addition of polyarginine (R6) into the same S/O nanoparticle containing OVA. The improved S/O nanodispersion system induced a comparable level of OVA-specific antibody to that induced by subcutaneous injection of OVA at the same dose, advocating the potential application of the S/O system as a needle-free and easy-to-use immunization system.