Cationic Niosomes for Enhanced Skin Immunization of Plasmid DNA-Encoding Ovalbumin via Hollow Microneedles

The purpose of the present study was to evaluate the use of cationic niosomes composed of Span20:cholesterol:cationic lipid (N ¹,N ¹-dimyristeroyloxyethyl-spermine) at the molar ratio of 2.5:2.5:0.5 mM combined with hollow microneedle (MN) devices for in vivo skin immunization of plasmid DNA-encoding ovalbumin (pOVA). The results revealed that using hollow MNs with cationic niosomes for pOVA penetration successfully induced both humoral and cell-mediated immune responses including immunoglobulin G (IgG) antibody responses, interleukin-4 (IL-4), and interferon gamma (IFN-γ) cytokine secretion. When using hollow MNs with cationic niosome/pOVA complexes, the immune response was superior to naked pOVA, which testifies the increased amount of IgG antibody responses and cytokine secretion. In comparison with conventional subcutaneous (SC) injections, using hollow MNs with cationic niosome/pOVA complexes induced a higher level of both IgG immune response and cytokine release. Moreover, a group of mice immunized with hollow MNs did not show infection or bleeding on the skin. Consequently, targeted delivery of pOVA using cationic niosomes combined with hollow MNs might prove a promising vaccination method for skin vaccination.