Dissolving Microneedle Arrays with Optimized Needle Geometry for Transcutaneous Immunization.

In this study, the feasibility of transcutaneous immunization using different needle-geometries dissolving microneedle array (DMNA) were investigated as drug carriers for ovalbumin (OVA) preparations. A two-step molding process was used in which needles were loaded with OVA. The microneedles displayed a geometry and dimensions consistent with the main molds. DMNA with different needle-geometries were compared and characterized. Drug loading of the prepared DMNAs reached ~100 μg measured via BCA assay. The stability of OVA in the DMNAs was investigated by SDS-PAGE electrophoresis and showed that the OVA encapsulated in the DMNAs was stable during preparation. The immune responses induced by the DMNAs and hypodermic needle-based injections were compared through in vivo immunoglobulin G (IgG) production assays. OVA-loaded DMNAs also induced stronger immune responses compared to hypodermic needle-based injections. In conclusion, these results suggest that: (1) the needle-morphology of DMNAs influences their mechanical properties, insertion capacity, and dissolution, thus affecting the immune response; (2) Cone-DMNAs are optimal for transcutaneous immunization. These data provide a theoretical basis for the use of transcutaneous immunization of DMNAs for vaccine development.