Flexible Dissolving Microneedle Array for Efficient DNA Vaccination by Electroporation-assisted Transdermal Immunization

DNA vaccination has emerged as an innovative approach for preventing and treating different diseases, including infectious diseases, cancers and autoimmune diseases. Although the results of ongoing clinical trials are promising, several limitations compromise the immunogenicity of these vaccines. Here, we presented a novel immune strategy that combined intradermal immunization with skin electroporation to enhance the immunogenicity of the DNA vaccine. A flexible dissolving microneedle array (FDMNA) was developed, comprising 400 pyramidal microneedles. The microneedle array included dissolving needles for delivering DNA vaccine and a flexible needle substrate for good tissue surface coverage. The FDMNA was completely dissolved within 10 minutes after being inserted into the skin and transported the DNA into the immune-cell-rich epidermis and dermis layer. In vivo immunogenicity test was performed to observe the ability of FDMNA-mediated intradermal electroporation to induce immune response. The electroporation voltage, pulse number and pulse duration were 100 V, 6 pulses and 50 ms, respectively. The result showed that, compared with the intramuscular vaccination, the FDMNA induced higher levels of antibody immune response against ovalbumin in mice. These findings demonstrated the potential utility of a Flexible Dissolving Microneedle Array(FDMNA)-based immune strategy for enhanced DNA vaccination.